P
USRE45987EExpiredUtilityPatentIndex 52

Electronic component and method of manufacturing the same

Assignee: RENESAS ELECTRONICS CORPPriority: Sep 11, 2003Filed: Aug 30, 2013Granted: Apr 26, 2016
Est. expirySep 11, 2023(expired)· nominal 20-yr term from priority
Inventors:OGAWA KENTA
H10W 90/756H10W 74/00H10W 72/5522H10W 72/952H10W 72/352H10W 72/325H10W 72/075H10W 72/59H10W 70/457H01L 2224/48091H01L 2224/85439H01L 2924/01013H01L 2924/00H01L 2924/3025H01L 2924/00014H01L 2224/45144H01L 2924/01079H01L 24/45H01L 2224/85444H01L 23/49582H01L 2924/19041H01L 24/48H01L 2924/01028H01L 2224/48639H01L 2924/01078H01L 2224/48644H01L 2224/29339H01L 2224/48247Y10T428/12708Y10S428/935Y10T428/12715Y10T428/12722
52
PatentIndex Score
0
Cited by
20
References
62
Claims

Abstract

An external terminal of an electronic component is provided with a lead base material and a metal thin film coating a surface of the lead base material, and an average value of a crystal size index is not less than 7, which is defined based on dimensions of a crystal particle in a direction perpendicular to the lead base material surface and in a direction parallel thereto, taken on a cut surface of the metal thin film defined by a given plane cutting the metal thin film in a direction perpendicular to the lead base material surface. Such constitution provides an electronic component having an external terminal coated with a metal thin film of a simple structure constituted of Sn or a Sn-based and substantially Pb-free alloy, formed by plating on a surface of a lead base material.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
       1. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material and including at least a first layer constituted of a material substantially Pb-free and predominantly composed of tin,
 wherein an average value of a crystal size index is not less than 7 when said crystal size index is defined as (a+b)/2, where a and b respectively represent dimensions in μm of a crystal particle constituting said first layer in a direction perpendicular to said lead base material surface and in a direction parallel thereto, taken on a cut surface of said first layer defined by a given plane cutting said first layer in a direction perpendicular to said lead base material surface. 
 
     
     
       2. The electronic component as recited in  claim 1 , wherein said first layer is constituted substantially of pure tin, or a tin-based alloy predominantly composed of tin and containing as an additive metal at least one out of the group consisting of bismuth, silver, copper, indium and zinc. 
     
     
       3. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material and including at least a first layer constituted of a material substantially Pb-free and predominantly composed of tin,
 wherein an average value of Xh/Xv is not less than 4, where Xv and Xh respectively represent dimensions of a crystal particle constituting said first layer in a direction perpendicular to said lead base material surface and in a direction parallel thereto, taken on a cut surface of said first layer defined by a given plane cutting said first layer in a direction perpendicular to said lead base material surface. 
 
     
     
       4. The electronic component as recited in  claim 3 , wherein said first layer is constituted substantially of pure tin, or a tin-based alloy predominantly composed of tin and containing as an additive metal at least one out of the group consisting of bismuth, silver, copper, indium and zinc. 
     
     
       5. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material and including at least a first layer constituted of a material substantially Pb-free and predominantly composed of tin, wherein said first layer is formed by plating, and a total extended length of a crystal particle boundary of said first layer is not more than 300 μm per 1000 μm 2  of observation area, on a cut surface parallel to a surface of said lead base material. 
     
     
       6. The electronic component as recited in  claim 5 , wherein said first layer is constituted substantially of pure tin, or a tin-based alloy predominantly composed of tin and containing as an additive metal at least one out of the group consisting of bismuth, silver, copper, indium and zinc. 
     
     
       7. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material and including at least a first layer constituted of a material substantially Pb-free and predominantly composed of tin, wherein said first layer in said metal thin film has an amorphous structure. 
     
     
       8. The electronic component as recited in  claim 7 , wherein said first layer is constituted substantially of pure tin, or a tin-based alloy predominantly composed of tin and containing as an additive metal at least one out of the group consisting of bismuth, silver, copper, indium and zinc. 
     
     
       9. The electronic component as recited in  claim 1 , wherein said first layer is constituted substantially of pure tin, and an average crystal size index of said first layer is in a range of 7 to 20. 
     
     
       10. The electronic component as recited in  claim 1 , wherein said first layer includes a tin-bismuth alloy predominantly composed of tin and containing not less than 0.5 wt % but not more than 4 wt % of bismuth, and an average crystal size index of said first layer is in a range of 7 to 20. 
     
     
       11. The electronic component as recited in  claim 1 , wherein said first layer includes a tin-silver alloy containing not less than 0.5 wt % but not more than 6 wt % of silver, and an average crystal size index of said first layer is in a range of 7 to 20. 
     
     
       12. The electronic component as recited in  claim 1 , wherein said first layer includes a tin-copper alloy containing not more than 3 wt % of copper, and an average crystal size index of said first layer is in a range of 10 to 30. 
     
     
       13. The electronic component as recited in  claim 1 , wherein said metal material is either a metal predominantly composed of copper, or an iron-nickel alloy. 
     
     
       14. A method of manufacturing an electronic component comprising an external terminal, including a lead base material constituted of a predetermined metal material and a metal thin film coating a surface of said lead base material, said metal thin film including at least a first layer constituted of a material substantially Pb-free and predominantly composed of tin, said first layer being formed by an electrolytic plating process,
 wherein said electrolytic plating process for forming said first layer includes an initial plating step of supplying a current having a current density not greater than 1 A/dm 2  during an initial stage of a predetermined duration of time.   
     
     
       15. The method as recited in  claim 14 , further comprising a heat treatment step of heating said first layer at a predetermined temperature for a predetermined time after said plating process,
 wherein said predetermined temperature in said heat treatment step is not more than a melting point of said first layer.   
     
     
       16. The method as recited in  claim 14 , further comprising a heat treatment step of heating said first layer at a predetermined temperature for a predetermined time after said plating process,
 wherein said heat treatment step includes melting step of heating said first layer at a temperature equal to or higher than a melting point thereof for a predetermined time and gradual cooling step of gradually cooling said first layer after said melting step, and   wherein a cooling rate in said gradual cooling step is not more than 3 degree centigrade per second.   
     
     
       17. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material and including a first layer constituted of a material substantially Pb-free and predominantly composed of tin,
 wherein an average value of a crystal size index is not less than 7 when said crystal size index is defined as (a+b)/2, where a and b respectively represent dimensions in μm of a crystal particle constituting said first layer in a direction perpendicular to said lead base material surface and in a direction parallel thereto, taken on a cut surface of said first layer defined by a given plane cutting said first layer in a direction perpendicular to said lead base material surface, and   wherein said first layer is composed of a plurality of crystal particles arranged in a single layer on said surface of said lead base material.   
     
     
       18. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material and including a first layer constituted of a material substantially Pb-free and predominantly composed of tin,
 wherein an average value of Xh/Xv is not less than 4, where Xv and Xh respectively represent dimensions of a crystal particle constituting said first layer in a direction perpendicular to said lead base material surface and in a direction parallel thereto, taken on a cut surface of said first layer defined by a given plane cutting said first layer in a direction perpendicular to said lead base material surface, and   wherein said first layer is composed of a plurality of the crystal particle arranged in a single layer on said surface of said lead base material.   
     
     
       19. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material and including a first layer constituted of a material substantially Pb-free and predominantly composed of tin,
 wherein said first layer is formed by plating, and a total extended length of a crystal particle boundary of said first layer is not more than 300 μm per 1000 μm 2  of observation area, on a cut surface parallel to a surface of said lead base material, and   wherein said first layer is composed of a crystal particle arranged in a single layer on said surface of said lead base material.   
     
     
       20. A method of manufacturing an electronic component comprising an external terminal, including a lead base material constituted of a predetermined metal material and a metal thin film coating a surface of said lead base material, said metal thin film including a first layer constituted of a material substantially Pb-free and predominantly composed of tin, said first layer being composed of a plurality of crystal particles arranged in a single layer on said surface of said lead base material, and said first layer being formed by an electrolytic plating process,
 wherein said electrolytic plating process for forming said first layer includes an initial plating step of supplying a current having a current density not greater than 1 A/dm 2  during an initial stage of a predetermined duration of time.   
     
     
       21. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material and including a first layer constituted of a material substantially Pb-free and predominantly composed of tin,
 wherein said lead base material comprises a plated layer underlying said first layer on which said first layer is formed, and   wherein an average value of a crystal size index is not less than 7 when said crystal size index is defined as (a+b)/2, where a and b respectively represent dimensions in μm of a crystal particle constituting said first layer in a direction perpendicular to said lead base material surface and in a direction parallel thereto, taken on a cut surface of said first layer defined by a given plane cutting said first layer in a direction perpendicular to said lead base material surface.   
     
     
       22. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material and including a first layer constituted of a material substantially Pb-free and predominantly composed of tin,
 wherein said lead base material comprises a plated layer underlying said first layer on which said first layer is formed, and   wherein an average value of Xh/Xv is not less than 4, where Xv and Xh respectively represent dimensions of a crystal particle constituting said first layer in a direction perpendicular to said lead base material surface and in a direction parallel thereto, taken on a cut surface of said first layer defined by a given plane cutting said first layer in a direction perpendicular to said lead base material surface.   
     
     
       23. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material and including a first layer constituted of a material substantially Pb-free and predominantly composed of tin,
 wherein said lead base material comprises a plated layer underlying said first layer on which said first layer is formed, and   wherein said first layer is formed by plating, and a total extended length of a crystal particle boundary of said first layer is not more than 300 μm per 1000 μm 2  of observation area, on a cut surface parallel to a surface of said lead base material.   
     
     
       24. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material and including a first layer constituted of a material substantially Pb-free and predominantly composed of tin,
 wherein said lead base material comprises a plated layer underlying said first layer on which said first layer is formed, and   wherein said first layer in said metal thin film has an amorphous structure.   
     
     
       25. A method of manufacturing an electronic component comprising an external terminal, including a lead base material constituted of a predetermined metal material and a metal thin film coating a surface of said lead base material, said metal thin film including a first layer constituted of a material substantially Pb-free and predominantly composed of tin, said first layer being composed of a plurality of crystal particles arranged in a single layer on said surface of said lead base material, and said first layer being formed by an electrolytic plating process,
 wherein said lead base material comprises a plated layer underlying said first layer on which said first layer is formed, and   wherein said electrolytic plating process for forming said first layer includes an initial plating step of supplying a current having a current density not greater than 1 A/dm 2  during an initial stage of a predetermined duration of time.   
     
     
       26. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material, said metal thin film being composed only of a first layer constituted of a material substantially Pb-free and predominantly composed of tin,
 wherein an average value of a crystal size index is not less than 7 when said crystal size index is defined as (a+b)/2, where a and b respectively represent dimensions in μm of a crystal particle constituting said first layer in a direction perpendicular to said lead base material surface and in a direction parallel thereto, taken on a cut surface of said first layer defined by a given plane cutting said first layer in a direction perpendicular to said lead base material surface.   
     
     
       27. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material, said metal thin film being composed only of a first layer constituted of a material substantially Pb-free and predominantly composed of tin,
 wherein an average value of Xh/Xv is not less than 4, where Xv and Xh respectively represent dimensions of a crystal particle constituting said first layer in a direction perpendicular to said lead base material surface and in a direction parallel thereto, taken on a cut surface of said first layer defined by a given plane cutting said first layer in a direction perpendicular to said lead base material surface.   
     
     
       28. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material, said metal thin film being composed only of a first layer constituted of a material substantially Pb-free and predominantly composed of tin,
 wherein said first layer is formed by plating, and a total extended length of a crystal particle boundary of said first layer is not more than 300 μm per 1000 μm 2  of observation area, on a cut surface parallel to a surface of said lead base material.   
     
     
       29. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material, said metal thin film being composed only of a first layer constituted of a material substantially Pb-free and predominantly composed of tin,
 wherein said first layer in said metal thin film has an amorphous structure.   
     
     
       30. A method of manufacturing an electronic component comprising an external terminal, including a lead base material constituted of a predetermined metal material and a metal thin film coating a surface of said lead base material, said metal thin film being composed only of a first layer constituted of a material substantially Pb-free and predominantly composed of tin, said first layer being composed of a plurality of crystal particles arranged in a single layer on said surface of said lead base material, and said first layer being formed by an electrolytic plating process,
 wherein said electrolytic plating process for forming said first layer includes an initial plating step of supplying a current having a current density not greater than 1 A/dm 2  during an initial stage of a predetermined duration of time.   
     
     
       31. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material and including a first layer constituted of a material substantially Pb-free and predominantly composed of tin,
 wherein an average value of a crystal size index is not less than 7 when said crystal size index is defined as (a+b)/2, where a and b respectively represent dimensions in μm of a crystal particle constituting said first layer in a direction perpendicular to said lead base material surface and in a direction parallel thereto, taken on a cut surface of said first layer defined by a given plane cutting said first layer in a direction perpendicular to said lead base material surface,   wherein said crystal particle is comprised of a columnar structure, and   wherein said first layer is composed of a plurality of columnar crystal particles arranged in a single layer on said surface of said lead base material.   
     
     
       32. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material and including a first layer constituted of a material substantially Pb-free and predominantly composed of tin,
 wherein an average value of Xh/Xv is not less than 4, where Xv and Xh respectively represent dimensions of a crystal particle constituting said first layer in a direction perpendicular to said lead base material surface and in a direction parallel thereto, taken on a cut surface of said first layer defined by a given plane cutting said first layer in a direction perpendicular to said lead base material surface,   wherein said crystal particle is comprised of a columnar structure, and   wherein said first layer is composed of a plurality of columnar crystal particles arranged in a single layer on said surface of said lead base material.   
     
     
       33. An electronic component comprising an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film coating a surface of said lead base material and including a first layer constituted of a material substantially Pb-free and predominantly composed of tin,
 wherein said first layer is formed by plating, and a total extended length of a crystal particle boundary of said first layer is not more than 300 μm per 1000 μm 2  of observation area, on a cut surface parallel to a surface of said lead base material, and   wherein said first layer is composed of a plurality of columnar crystal particles arranged in a single layer on said surface of said lead base material.   
     
     
       34. A method of manufacturing an electronic component comprising an external terminal, including a lead base material constituted of a predetermined metal material and a metal thin film coating a surface of said lead base material, said metal thin film including a first layer constituted of a material substantially Pb-free and predominantly composed of tin, said first layer being composed of a plurality of columnar crystal particles arranged in a single layer on said surface of said lead base material, and said first layer being formed by an electrolytic plating process,
 wherein said electrolytic plating process for forming said first layer includes an initial plating step of supplying a current having a current density not greater than 1 A/dm 2  during an initial stage of a predetermined duration of time.   
     
     
       35. An electronic component, comprising:
 an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film covering a surface of said lead base material,   wherein said metal thin film has a first layer made of a material substantially Pb-free;   wherein said first layer is made of a material predominantly composed of tin;   wherein an average value of a crystal size index of a crystal particle constituting said first layer is greater than or equal to 7 μm,   wherein said crystal size index defines a value obtained by dividing a sum of a size in a first direction and a size in a second direction by 2, in said crystal particle seen in a cross section of said first layer;   wherein said cross section of said first layer is a given surface cutting said first layer in said first direction;   wherein said first direction is a direction, which is perpendicular to said surface of said lead base material; and   wherein said second direction is a direction, which is parallel to said surface of said lead base material.   
     
     
       36. An electronic component, comprising:
 an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film covering a surface of said lead base material,   wherein said metal thin film has a first layer made of a material substantially Pb-free;   wherein said first layer is made of a material predominantly composed of tin;   wherein an average value of Xh/Xv of a crystal particle constituting said first layer is greater than or equal to 4,   wherein Xv is a size in a first direction perpendicular to said surface of said lead base material, in said crystal particle seen in a cross section of said first layer;   wherein Xh is a size in a second direction parallel to said surface of said lead base material, in said crystal particle seen in said cross section of said first layer; and   wherein said cross section of said first layer is a given surface cutting said first layer in said first direction.   
     
     
       37. An electronic component, comprising:
 an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film covering a surface of said lead base material,   wherein said metal thin film has a first layer made of a material substantially Pb-free;   wherein said first layer is made of a material predominantly composed of tin;   wherein said first layer is formed by plating;   wherein a total extended length of a crystal particle boundary of said first layer is less than or equal to 300 μm per 1000 μm 2  of observation area; and   wherein said observation area is a cut surface parallel to said surface of said lead base material.   
     
     
       38. An electronic component, comprising:
 an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film covering a surface of said lead base material,   wherein said metal thin film has a first layer made of a material substantially Pb-free;   wherein said first layer is made of a material predominantly composed of tin; and   wherein said first layer in said metal thin film has an amorphous structure.   
     
     
       39. An electronic component, comprising:
 an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film covering a surface of said lead base material,   wherein said metal thin film has a first layer made of a material substantially Pb-free;   wherein said first layer is made of a material predominantly composed of tin;   wherein an average value of a crystal size index of a crystal particle constituting said first layer is greater than or equal to 7 μm,   wherein said crystal size index defines a value obtained by dividing a sum of a size in a first direction and a size in a second direction by 2, in said crystal particle seen in a cross section of said first layer;   wherein said cross section of said first layer is a given surface cutting said first layer in said first direction;   wherein said first direction is a direction, which is perpendicular to said surface of said lead base material;   wherein said second direction is a direction, which is parallel to said surface of said lead base material; and   wherein said first layer is composed of a plurality of crystal particles arranged in a single layer on said surface of said lead base material.   
     
     
       40. An electronic component, comprising:
 an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film covering a surface of said lead base material,   wherein said metal thin film has a first layer made of a material substantially Pb-free;   wherein said first layer is made of a material predominantly composed of tin;   wherein an average value of Xh/Xv of a crystal particle constituting said first layer is greater than or equal to 4,   wherein Xv is a size in a first direction perpendicular to said surface of said lead base material, in said crystal particle seen in a cross section of said first layer;   wherein Xh is a size in a second direction parallel to said surface of said lead base material, in said crystal particle seen in said cross section of said first layer;   wherein said cross section of said first layer is a given surface cutting said first layer in said first direction; and   wherein said first layer is composed of a plurality of crystal particles arranged in a single layer on said surface of said lead base material.   
     
     
       41. An electronic component, comprising:
 an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film covering a surface of said lead base material,   wherein said metal thin film has a first layer made of a material substantially Pb-free;   wherein said first layer is made of a material predominantly composed of tin;   wherein said first layer is formed by plating;   wherein a total extended length of a crystal particle boundary of said first layer is less than or equal to 300 μm per 1000 μm 2  of observation area;   wherein said observation area is a cut surface parallel to said surface of said lead base material; and   wherein said first layer is composed of a plurality of crystal particles arranged in a single layer on said surface of said lead base material.   
     
     
       42. A method of manufacturing an electronic component comprising an external terminal, including a lead base material constituted of a predetermined metal material and a metal thin film covering a surface of said lead base material, said metal thin film having a first layer made of a material substantially Pb-free and made of a material predominantly composed of tin, said first layer is composed of a plurality of crystal particles arranged in a single layer on said surface of said lead base material, and said first layer being formed by an electrolytic plating process,
 wherein said electrolytic plating process for forming said first layer includes an initial plating step of supplying a current having a current density less than or equal to 1 A/dm 2  during an initial stage of a predetermined duration of time.   
     
     
       43. An electronic component, comprising:
 an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film covering a surface of said lead base material,   wherein said metal thin film has a first layer made of a material substantially Pb-free;   wherein said first layer is made of a material predominantly composed of tin;   wherein an average value of a crystal size index of a crystal particle constituting said first layer is greater than or equal to 7 μm,   wherein said crystal size index defines a value obtained by dividing a sum of a size in a first direction and a size in a second direction by 2, in said crystal particle seen in a cross section of said first layer;   wherein said cross section of said first layer is a given surface cutting said first layer in said first direction;   wherein said first direction is a direction, which is perpendicular to said surface of said lead base material;   wherein said second direction is a direction, which is parallel to said surface of said lead base material;   wherein said first layer is composed of a plurality of crystal particles arranged in a single layer on said surface of said lead base material; and   wherein said first layer is the uppermost layer to be contacted with a solder.   
     
     
       44. An electronic component, comprising:
 an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film covering a surface of said lead base material,   wherein said metal thin film has a first layer made of a material substantially Pb-free;   wherein said first layer is made of a material predominantly composed of tin;   wherein an average value of Xh/Xv of a crystal particle constituting said first layer is greater than or equal to 4,   wherein Xv is a size in a first direction perpendicular to said surface of said lead base material, in said crystal particle seen in a cross section of said first layer;   wherein Xh is a size in a second direction parallel to said surface of said lead base material, in said crystal particle seen in said cross section of said first layer;   wherein said cross section of said first layer is a given surface cutting said first layer in said first direction;   wherein said first layer is composed of a plurality of crystal particles arranged in a single layer on said surface of said lead base material; and   wherein said first layer is the uppermost layer to be contacted with a solder.   
     
     
       45. An electronic component, comprising:
 an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film covering a surface of said lead base material,   wherein said metal thin film has a first layer made of a material substantially Pb-free;   wherein said first layer is made of a material predominantly composed of tin;   wherein an average value of a crystal size index of a crystal particle constituting said first layer is greater than or equal to 7 μm,   wherein said crystal size index defines a value obtained by dividing a sum of a size in a first direction and a size in a second direction by 2, in said crystal particle seen in a cross section of said first layer;   wherein said cross section of said first layer is a given surface cutting said first layer in said first direction;   wherein said first direction is a direction, which is perpendicular to said surface of said lead base material;   wherein said second direction is a direction, which is parallel to said surface of said lead base material;   wherein said first layer is composed of a plurality of crystal particles arranged in a single layer on said surface of said lead base material; and   wherein said average value of said crystal size index is obtained by continuously arranged crystal particles more than or equal to 5 particles.   
     
     
       46. An electronic component, comprising:
 an external terminal including a lead base material constituted of a predetermined metal material, and a metal thin film covering a surface of said lead base material,   wherein said metal thin film has a first layer made of a material substantially Pb-free;   wherein said first layer is made of a material predominantly composed of tin;   wherein an average value of Xh/Xv of a crystal particle constituting said first layer is greater than or equal to 4,   wherein Xv is a size in a first direction perpendicular to said surface of said lead base material, in said crystal particle seen in a cross section of said first layer;   wherein Xh is a size in a second direction parallel to said surface of said lead base material, in said crystal particle seen in said cross section of said first layer;   wherein said cross section of said first layer is a given surface cutting said first layer in said first direction;   wherein said first layer is composed of a plurality of crystal particles arranged in a single layer on said surface of said lead base material; and   wherein said average value of said crystal size index is obtained by continuously arranged crystal particles more than or equal to 5 particles.   
     
     
       47. The electronic component as recited in claim 17, wherein a thickness of said single layer is defined by a thickness of each of said crystal particles. 
     
     
       48. The electronic component as recited in claim 18, wherein a thickness of said single layer is defined by a thickness of each of said crystal particles. 
     
     
       49. The electronic component as recited in claim 19, wherein a thickness of said single layer is defined by a thickness of each of said crystal particles. 
     
     
       50. The method as recited in claim 20, wherein a thickness of said single layer is defined by a thickness of each of said crystal particles. 
     
     
       51. The electronic component as recited in claim 31, wherein a thickness of said single layer is defined by a thickness of each of said crystal particles. 
     
     
       52. The electronic component as recited in claim 32, wherein a thickness of said single layer is defined by a thickness of each of said crystal particles. 
     
     
       53. The electronic component as recited in claim 33, wherein a thickness of said single layer is defined by a thickness of each of said crystal particles. 
     
     
       54. The method as recited in claim 34, wherein a thickness of said single layer is defined by a thickness of each of said crystal particles. 
     
     
       55. The electronic component as recited in claim 39, wherein a thickness of said single layer is defined by a thickness of each of said crystal particles. 
     
     
       56. The electronic component as recited in claim 40, wherein a thickness of said single layer is defined by a thickness of each of said crystal particles. 
     
     
       57. The electronic component as recited in claim 41, wherein a thickness of said single layer is defined by a thickness of each of said crystal particles. 
     
     
       58. The method as recited in claim 42, wherein a thickness of said single layer is defined by a thickness of each of said crystal particles. 
     
     
       59. The electronic component as recited in claim 43, wherein a thickness of said single layer is defined by a thickness of each of said crystal particles. 
     
     
       60. The electronic component as recited in claim 44, wherein a thickness of said single layer is defined by a thickness of each of said crystal particles. 
     
     
       61. The electronic component as recited in claim 45, wherein a thickness of said single layer is defined by a thickness of each of said crystal particles. 
     
     
       62. The electronic component as recited in claim 46, wherein a thickness of said single layer is defined by a thickness of each of said crystal particles.

Cited by (0)

No later patents cite this yet.

References (0)

No backward citations on record.