System and method for detecting bonding status of bonding wire of semiconductor package

Abstract

The present invention provides schemes which are associated with wire bonding process or wire bonding machine to detect the bonding status of a bonding wire of a package including at least a semiconductor unit. The schemes are very useful to a BGA (Ball Grid Array) package or similar types of packages, and provide significant advantages particularly for a package in which the resistance (such as the resistance resulting from an adhesion layer and a layer of Cupric Oxide for promoting adhesion) between a semiconductor unit and its carrier is not low enough. The present invention is characterized in that a preset connection between a semiconductor unit and a package-connection-area (such as the solder ball pad of a ball grid array package) is established in the beginning of a wire bonding process, and the package-connection-area is electrically connected with a press plate used by the wire bonding machine or the wire bonding process, so that a current loop can be formed via a bonding wire, the preset connection, the package-connection-area, and the press plate when the bonding wire is bonded to a semiconductor unit, and the bonding status between the bonding wire and the semiconductor unit can be indicated according to the current flowing through the current loop. The present invention is also applicable to the detection of bonding status between a bonding wire and a bonding finger electrically connected to a package-connection-area of the package.

What is claimed is:  
     
         1 . A system associated with a wire bonding process, for detecting bonding status of at least a bonding wire of a package including at least a semiconductor unit and at least a package-connection-means, said system comprising: 
 at least a carrier for supporting said semiconductor unit and said package connection means;    at least an electrical conduction means contacting at least a selected one of said package-connection-means;    at least a preset connection means for electrically connecting the selected one of said connection means and said semiconductor unit;    a voltage source for providing an electrical potential difference between said electrical conduction means and said bonding wire;    a detector for measuring, when said bonding wire is electrically connected to at least one of said semiconductor unit and said package-connection-means, a current passing said voltage source, and for providing, according to the measured current, at least a status indicating signal reflecting the bonding status of said bonding wire.    
     
     
         2 . The system according to  claim 1  wherein said electrical conduction means is made of at least one selected from among electrically conductive metal, electrically conductive rubber, and anisotropically conductive film.  
     
     
         3 . The system according to  claim 1  wherein said package-connection-means is solder ball pad.  
     
     
         4 . The system according to  claim 1  wherein said carrier is made of at least one selected from substrate, tape, and heat dissipater.  
     
     
         5 . The system according to  claim 1  wherein the carrier supporting said semiconductor unit is a heat dissipater to which said semiconductor unit is attached via adhesive material and cupric oxide.  
     
     
         6 . The system according to  claim 1  wherein said preset connection means comprises a bonding finger and a preset bonding wire, said bonding finger being on the carrier supporting said package-connection-means, and electrically connecting the selected one of said package-connection-means, said preset bonding wire electrically connecting said bonding finger and said semiconductor unit.  
     
     
         7 . The system according to  claim 6  wherein said preset bonding wire is bonded, according to said wire bonding process, to said bonding finger and a corresponding wire bonding pad which is a wire bonding pad of said semiconductor unit and which corresponds to the selected one of said package-connection-means.  
     
     
         8 . The system according to  claim 6  wherein said preset connection means further comprises a trace lying on said carrier and electrically connecting said bonding finger and the selected one of said package-connection-means.  
     
     
         9 . The system according to  claim 1  wherein said voltage source provides the electrical potential difference between said electrical conduction means and said bonding wire via a press plate connecting said voltage source, and via a bonding wire provider and a bonding wire which is in a capillary and electrically connected to said electrical conduction means, said press plate and said bonding wire provider as well as said capillary all being used in said wire bonding process, said press plate contacting said electrical conduction means.  
     
     
         10 . The system according to  claim 1  wherein said voltage source electrically connects said bonding wire and a press plate used in said wire bonding process, said press plate contacting said electrical conduction means; and wherein said detector provides said status indicating signal according to the measured current when said wire bonding process completes bonding said bonding wire to said semiconductor unit, said status indicating signal reflecting whether or not the bonding status between said bonding wire and said semiconductor unit is good.  
     
     
         11 . The system according to  claim 1  wherein said electrical conduction means contacts all of said package-connection-means.  
     
     
         12 . The system according to  claim 11  wherein said detector provides a first status indicating signal according to the measured current when said wire bonding process completes bonding said bonding wire to said semiconductor unit, said first status indicating signal indicating whether or not the bonding status between said bonding wire and said semiconductor unit is good.  
     
     
         13 . The system according to  claim 11  wherein the carrier supporting said package-connection-means comprises at least a bonding finger each electrically connecting one of said package-connection-means; and wherein said detector provides a second status indicating signal according to the measured current when said wire bonding process completes bonding said bonding wire to said bonding finger, said second status indicating signal indicating whether or not the bonding status between said bonding wire and said bonding finger is good.  
     
     
         14 . The system according to  claim 11  wherein the carrier supporting said package-connection-means comprises at least a bonding finger each electrically connecting one of said package-connection-means; and wherein said voltage source electrically connects said bonding wire and a press plate used in said wire bonding process, said press plate contacting said electrical conduction means; and wherein said detector provides a first status indicating signal according to the measured current when said wire bonding process completes bonding said bonding wire to said semiconductor unit, said first status indicating signal indicating whether or not the bonding status between said bonding wire and said semiconductor unit is good, said detector also provides a second status indicating signal according to the measured current when said wire bonding process completes bonding said bonding wire to said bonding finger, said second status indicating signal indicating whether or not the bonding status between said bonding wire and said bonding finger is good.  
     
     
         15 . The system according to  claim 1  wherein said voltage source and said detector are attached to an apparatus used in said wire bonding process.  
     
     
         16 . A method associated with a wire bonding machine, for detecting bonding status of a bonding wire of a package including at least a semiconductor unit and at least a package-connection-means, said semiconductor unit and said package-connection-means being supported by at least a carrier with said package-connection-means exposed, said method comprising the steps of: 
 selecting at least one of said package-connection-means to be contacted by a electrical conduction means;    electrically connecting said semiconductor unit and the selected one of said package-connection-means;    letting a press plate of said wire bonding machine contact said electrical conduction means;    using a voltage source to provide an electrical potential difference which exists between said press plate and said bonding wire when said wire bonding machine completes bonding said bonding wire to said semiconductor unit;    measuring a current passing said voltage source, and providing a status indicating signal according to the measured current to reflect the bonding status between said bonding wire and said semiconductor unit.    
     
     
         17 . The method according to  claim 16  wherein said electrical conduction means is made of at least one selected from among electrically conductive metal, electrically conductive rubber, and anisotropically conductive film.  
     
     
         18 . The method according to  claim 16  wherein said package-connection-means is solder ball pad.  
     
     
         19 . The method according to  claim 16  wherein the step of electrically connecting the selected one of said package-connection-means and said semiconductor unit comprises a step of electrically connecting the selected one of said package-connection-means and a point of said semiconductor unit.  
     
     
         20 . The method according to  claim 16  wherein the step of electrically connecting the selected one of said package-connection-means and said semiconductor unit comprises a step of electrically connecting the selected one of said package-connection-means and a corresponding wire bonding pad which is a wire bonding pad of said semiconductor unit and corresponds to the selected one of said package-connection-means.  
     
     
         21 . The method according to  claim 16  wherein the carrier supporting the selected one of said package-connection-means includes at least a trace and at least a bonding finger, each of said package-connection-means connecting said bonding finger via said trace; and wherein the step of electrically connecting the selected one of said package-connection-means and said semiconductor unit includes the step of: bonding a preset connection means by said wire bonding machine between the bonding finger connected to the selected one of said package-connection-means, and a corresponding wire bonding pad which is a wire bonding pad of said semiconductor unit and corresponds to the selected one of said package-connection-means.  
     
     
         22 . The method according to  claim 16  wherein said electrical potential difference between said press plate and said bonding wire is provided by connecting a voltage source to said press plate and said bonding wire.  
     
     
         23 . A method associated with a wire bonding machine, for detecting bonding status of a bonding wire of a package including at least a semiconductor unit and at least a package-connection-means, said semiconductor unit and said package-connection-means being supported by at least a carrier with said package-connection-means exposed, said method comprising the steps of: 
 contacting all of said package-connection-means by an electrical conduction means;    selecting at least one of said package-connection-means to electrically connect said semiconductor unit;    letting a press plate of said wire bonding machine contact said electrical conduction means;    using a voltage source to provide an electrical potential difference which exists between said press plate and said bonding wire when said wire bonding machine completes bonding said bonding wire to said semiconductor unit;    measuring a current passing said voltage source, and providing a status indicating signal according to the measured current to reflect the bonding status between said bonding wire and said semiconductor unit.    
     
     
         24 . The method according to  claim 23  wherein said electrical conduction means is made of at least one selected from among electrically conductive metal, electrically conductive rubber, and anisotropically conductive film.  
     
     
         25 . The method according to  claim 23  wherein said package-connection-means is solder ball pad.  
     
     
         26 . The method according to  claim 23  wherein the step of electrically connecting the selected one of said package-connection-means and said semiconductor unit comprises a step of electrically connecting the selected one of said package-connection-means and a point of said semiconductor unit.  
     
     
         27 . The method according to  claim 23  wherein the step of electrically connecting the selected one of said package-connection-means and said semiconductor unit comprises a step of electrically connecting the selected one of said package-connection-means and a corresponding wire bonding pad which is a wire bonding pad of said semiconductor unit and corresponds to the selected one of said package-connection-means.  
     
     
         28 . The method according to  claim 23  wherein the step of electrically connecting the selected one of said package-connection-means and said semiconductor unit comprises the steps of: bonding a wire to said semiconductor unit; and bonding said wire to a bonding finger electrically connecting the selected one of said package-connection-means via at least a trace lying on the carrier supporting said package-connection-means.  
     
     
         29 . The method according to  claim 23  wherein said electrical potential difference is applied to said press plate and said bonding wire by connecting a voltage source to said press plate and said bonding wire.  
     
     
         30 . The method according to  claim 23  wherein the carrier supporting said package-connection-means includes at least a bonding finger each electrically connecting one of said package-connection-means, and said electrical potential difference also exists between said press plate and said bonding wire when said wire bonding machine completes bonding said bonding wire to said bonding finger; and wherein said detector also measures, when said wire bonding machine completes bonding said bonding wire to said bonding finger, the current passing said voltage source to provide another status indicating signal according to the current so measured, said another status indicating signal indicating the bonding status between said bonding wire and said bonding finger.  
     
     
         31 . The method according to  claim 30  wherein said bonding finger electrically connects said package-connection-means via at least a trace on the carrier supporting said package-connection-means.  
     
     
         32 . The method according to  claim 30  wherein said status indicating signal includes two components, the first one of said two components reflecting whether the electrical connection status between said bonding wire and said semiconductor unit is good or not, the second one of said two components reflecting whether the electrical connection status between said bonding wire and said package-connection-means is good or not.