Patent Application
20080304245
This application claims the priority benefit of Taiwan Patent Application Serial Number 096120685 filed Jun. 8, 2007, the full disclosure of which is incorporated herein by reference.
1. Field of the Invention
The invention relates to a method for discharging electronic devices, and more particularly, to a method for discharging electronic devices on a substrate. The invention also relates to a semiconductor package.
2. Description of the Related Art
According to conventional semiconductor package processes, in order to electrically connect a chip to the substrate on which the chip is mounted, a wire bonder is typically used to connect wires from the chip to the substrate. Generally, to make easy to achieve the wire bonding, one end of a bonding wire is first bonded to one of the bonding pads on the chip and the other end of the bonding wire is then bonded to the corresponding finger on the substrate. However, some devices, such as capacitors mounted to the substrate may have been fully charged prior to the wire bonding process. In the event that the charged capacitors have been in electrical connection with the corresponding finger, the charge stored in the capacitors can be conducted to the chip through the bonding wire when the wire is first bonded to the chip and then to the corresponding finger to form an electrical connection between the chip and the finger. As a result, the current resulted from the charge flow from the capacitors to the chip is likely to damage the chip.
Accordingly, there exists a need to provide a method for discharging electronic devices on a substrate to solve the above-mentioned problems.
It is an object of the present invention to provide a method for discharging electronic devices on a substrate. Prior to wire bonding from a chip to a finger on the substrate, the charge previously stored in the electronic devices is discharged in order to prevent the current from occurring due to an electrical connection between the chip and the finger formed in the wire bonding process to damage the chip.
In one embodiment, the method for discharging electronic devices on a substrate is to provide a wire bonder with a metal pin electrically connecting to the wire bonder. When wanting to discharge an electronic device, such as capacitor on a substrate, the metal pin is brought into electrical contact with a specific finger which is in electrical connection with the electronic device. As a result, the charge previously stored in the electronic device will be conducted to the wire bonder through the specific finger and the metal pin thereby discharging the stored charge.
In another embodiment, the method for discharging electronic devices on a substrate is first to heat a metal wire protruding out from a capillary of a wire bonder to form a metal ball at the capillary. Afterward, the capillary is moved to bring the metal ball into contact with the first portion of the finger. As a result, the charge previously stored in the electronic device will be conducted to the wire bonder through the finger, the metal ball and the metal wire thereby discharging the stored charge.
The present invention further provides a semiconductor package. After the metal ball has been formed on the first portion of the finger, a metal wire is used to electrically connect the chip to the second portion of the finger. Finally, a sealant is formed on the substrate to encapsulate the chip, metal ball, metal wire, finger and electronic device.
The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.
a and 2b illustrate the method for discharging electronic devices on a substrate according to the second embodiment of the present invention.
c illustrates that a metal ball is left on the finger of the substrate after the performance of the method according to the second embodiment of the present invention.
Referring to
The method described above can be performed prior to or subsequent to the attachment of a chip 140 to the substrate 120 but is required to be carried out before the wire bonding. This will prevent the current from occurring due to an electrical connection between the chip 140 and the specific finger 122 on the substrate 120 formed in the wire bonding process to damage the chip 140.
Referring to
After the charge stored in the electronic device 130 is discharged, both the original wire bonder 210 and capillary 212 can continue to be used to perform the wire bonding from the chip 140 to the finger 122 without need to change the wire bonder 210 and capillary 212. Accordingly, the time for changing these wire-bonding facilities can be saved. Furthermore, referring to
Referring to
Although the preferred embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 096120685 | Jun 2007 | TW | national |
