Multi-layer circuit board

Abstract

A multi-layer circuit board includes first, second, third, fourth, fifth, sixth and seventh insulating substrates disposed sequentially one above the other; first, second, third and fourth signal wiring layers; first, second and third ground wiring layers; and a power wiring layer. Each of the first and seventh insulating substrates has a thickness ranging from 2.5 to 7.5 mil. Each of the second and sixth insulating substrates has a thickness ranging from 3 to 13 mil. Each of the third and fifth insulating substrates has a thickness ranging from 3 to 15 mil. The fourth insulating substrate has a thickness ranging from 2 to 6 mil. The first signal wiring layer has a first resistance with respect to the first ground wiring layer. The second signal wiring layer has a second resistance with respect to the first and second ground wiring layers. The third signal wiring layer has a third resistance with respect to the third ground wiring layer and the power wiring layer. The fourth signal wiring layer has a fourth resistance with respect to the third ground wiring layer. The first, second, third and fourth resistances are within the range of 49.5 to 60.5 ohms.

1. A multi-layer circuit board comprising:
 first, second, third, fourth, fifth, sixth and seventh insulating substrates disposed sequentially one above the other;  
 a first signal wiring layer disposed on one side of said first insulating substrate opposite to said second insulating substrate;  
 a first ground wiring layer disposed between said first and second insulating substrates;  
 a second signal wiring layer disposed between said second and third insulating substrates;  
 a second ground wiring layer disposed between said third and fourth insulating substrates;  
 a power wiring layer disposed between said fourth and fifth insulating substrates;  
 a third signal wiring layer disposed between said fifth and sixth insulating substrates;  
 a third ground wiring layer disposed between said sixth and seventh insulating substrates; and  
 a fourth signal wiring layer disposed on one side of said seventh insulating substrate opposite to said sixth insulating substrate;  
 wherein each of said first and seventh insulating substrates has a thickness ranging from 2.5 to 7.5 mil;  
 wherein each of said second and sixth insulating substrates has a thickness ranging from 3 to 13 mil;  
 wherein each of said third and fifth insulating substrates has a thickness ranging from 3 to 15 mil;  
 wherein said fourth insulating substrate has a thickness ranging from 2 to 6 mil;  
 wherein said first signal wiring layer has a first resistance with respect to said first ground wiring layer, said second signal wiring layer having a second resistance with respect to said first and second ground wiring layers, said third signal wiring layer having a third resistance with respect to said third ground wiring layer and said power wiring layer, said fourth signal wiring layer having a fourth resistance with respect to said third ground wiring layer; and  
 wherein said first, second, third and fourth resistances are within the range of 49.5 to 60.5 ohms.  
 
     
     
       2. The multi-layer circuit board of  claim 1 , wherein at least one of said first, third, fifth and seventh insulating substrates is made from a polyester prepreg. 
     
     
       3. The multi-layer circuit board of  claim 1 , wherein at least one of said second, fourth and sixth insulating substrates is made from a fibrous core material. 
     
     
       4. The multi-layer circuit board of  claim 3 , wherein the core material contains paper fibers. 
     
     
       5. The multi-layer circuit board of  claim 3 , wherein the core material contains glass fibers. 
     
     
       6. The multi-layer circuit board of  claim 1 , wherein the thicknesses of said first and seventh insulating substrates are equal. 
     
     
       7. The multi-layer circuit board of  claim 1 , wherein the thicknesses of said second and sixth insulating substrates are equal. 
     
     
       8. The multi-layer circuit board of  claim 1 , wherein the thicknesses of said third and fifth insulating substrates are equal. 
     
     
       9. The multi-layer circuit board of  claim 1 , wherein:
 each of said first and fourth signal wiring layers has a thickness of about 1.4 mil; and  
 each of said second and third signal wiring layers, said first, second and third ground wiring layers, and said power wiring layer has a thickness of about 0.7 mil.  
 
     
     
       10. The multi-layer circuit board of  claim 1 , wherein:
 each of said first and seventh insulating substrates has a thickness of 4.5±2 mil;  
 each of said second and sixth insulating substrates has a thickness of 6±3 mil;  
 each of said third and fifth insulating substrates has a thickness of 7±4 mil; and  
 said first, second, third, fourth, fifth, sixth and seventh insulating substrates, said first, second, third and fourth signal wiring layers, said first, second and third ground wiring layers, and said power wiring layer are press-bonded to each other to form said circuit board with a thickness of about 1.2 mm.  
 
     
     
       11. The multi-layer circuit board of  claim 10 , wherein:
 each of said first and seventh insulating substrates has a thickness of 4.5 mil;  
 each of said second and sixth insulating substrates has a thickness of 6 mil;  
 each of said third and fifth insulating substrates has a thickness of 7 mil; and  
 said fourth insulating substrate has a thickness of 4 mil.  
 
     
     
       12. The multi-layer circuit board of  claim 1 , wherein:
 each of said first and seventh insulating substrates has a thickness of 5.5±2 mil;  
 each of said second and sixth insulating substrates has a thickness of 10±3 mil;  
 each of said third and fifth insulating substrates has a thickness of 11±4 mil; and  
 said first, second, third, fourth, fifth, sixth and seventh insulating substrates, said first, second, third and fourth signal wiring layers, said first, second and third ground wiring layers, and said power wiring layer are press-bonded to each other to form said circuit board with a thickness of about 1.6 mm.  
 
     
     
       13. The multi-layer circuit board of  claim 12 , wherein:
 each of said first and seventh insulating substrates has a thickness of 5.5 mil;  
 each of said second and sixth insulating substrates has a thickness of 10 mil;  
 each of said third and fifth insulating substrates has a thickness of 11 mil; and  
 said fourth insulating substrate has a thickness of 4 mil.  
 
     
     
       14. A multi- layer circuit board comprising:      first, second, third, fourth, fifth, sixth and seventh insulating substrates disposed sequentially one above the other;        a first signal wiring layer disposed on one side of said first insulating substrate opposite to said second insulating substrate;        a first wiring layer disposed between said first and second insulating substrates;        a second signal wiring layer disposed between said second and third insulating substrates;        a second wiring layer disposed between said third and fourth insulating substrates;        a third wiring layer disposed between said fourth and fifth insulating substrates;        a third signal wiring layer disposed between said fifth and sixth insulating substrates;        a fourth wiring layer disposed between said sixth and seventh insulating substrates; and        a fourth signal wiring layer disposed on one side of said seventh insulating substrate opposite to said sixth insulating substrate;        wherein each of said first and seventh insulating substrates has a thickness ranging from  2 . 5  to  7 . 5  mil;        wherein each of said second and sixth insulating substrates has a thickness ranging from  3  to  13  mil;        wherein each of said third and fifth insulating substrates has a thickness ranging from  3  to  15  mil;        wherein a signal trace of said first signal wiring layer has a first resistance with respect to said first wiring layer, a signal trace of said second signal wiring layer having a second resistance with respect to said first and second wiring layers, a signal trace of said third signal wiring layer having a third resistance with respect to said third and fourth wiring layers, a signal trace of said fourth signal wiring layer having a fourth resistance with respect to said fourth wiring layer; and        wherein said first, second, third and fourth resistances are within the range of  49 . 5  to  60 . 5  ohms.     
     
     
       15. The multi- layer circuit board of    claim 14   , wherein said first, second, third, and fourth wiring layers are a first ground wiring layer, a second ground wiring layer, a power wiring layer, and a third ground wiring layer, respectively.   
     
     
       16. The multi- layer circuit board of    claim 14   , wherein said fourth insulating substrate has a thickness ranging from  2  to  6  mil.   
     
     
       17. The multi- layer circuit board of    claim 14   , wherein one of said first, second, third, and fourth wiring layers is a ground wiring layer.   
     
     
       18. The multi- layer circuit board of    claim 14   , wherein one of said first, second, third, and fourth wiring layers is a power wiring layer.