Electronic package structure and method
An electronic package structure and method use a conductive strip to bond die-to-die, die-to-lead, chip carrier-to-lead, or lead-to-lead. A conductive strip may carry greater current than a bonding wire, and thus may replace several bonding wires. The bonding of the conductive strip may be carried out by an SMT process, and thus requires lower cost than wire bonding processes. A conductive strip may be bonded to more than two dice or leads to save more bonding wires. A conductive strip is stronger than a bonding wire, and thus lowers the possibility of being broken.
The present invention is related generally to integrated circuit (IC) products and, more particularly, to an electronic package structure and method.
BACKGROUND OF THE INVENTIONIn a typical semiconductor process, dice are cut from wafers by a dicing process, then each die is attached to a package substrate or a chip carrier of a leadframe, the inputs/outputs of the die are electrically connected to leads of the leadframe by a bonding process, and finally, plastic, ceramic or metal is used to encapsulate the die except that the outer leads of the leadframe are left exposed outside the package for connecting to other electronic components. This process is called electronic package method. With the protection of the electronic package, the IC components in the die may avoid damages from external environment or forces.
For an electronic package, there are three popular bonding processes, wire bonding, tape automatic bonding (TAB) and flip-chip bonding, among which the wire bonding is the most often used. The wire bonding process uses a bonder to bond one end of a wire to a bonding pad on a die and the other end to a lead of a leadframe. The commonly used wires include aluminum wires, gold wires, silver wires and so on. The thickness of a single wire or the number of wires will be proportional to the current to be carried. The greater the current to be carried, the larger the thickness of a single wire or the number of wires is. For instance, for power input and output of a power management chip, sometimes more than five bonding wires are bonded to a bonding pad of the chip because great current will flow therethrough. Such high current applications result in high cost and low yield packages. In some circumstances, for example, if non-uniform contact resistance is present between several wires bonded on a same bonding pad, or some of the bonding wires are broken, there will be a single one among the bonding wires carrying the high current and thus being broken.
SUMMARY OF THE INVENTIONAn object of the present invention is to provide an electronic package structure for high current applications.
Another object of the present invention is to provide a stronger electronic package structure.
Still another object of the present invention is to provide a low-cost electronic package structure and method.
According to the present invention, an electronic package structure comprises a conductive strip to bond die-to-die, die-to-lead, chip carrier-to-lead, or lead-to-lead.
A conductive strip may carry greater current than a bonding wire, and thus may replace several bonding wires.
The bonding of the conductive strip may be carried out by a surface mounting technology (SMT). Preferably, the conductive strip is applied with a bonding material thereon and then bonded to a bump on a die. Alternatively, the bonding material is spotted or printed on a chip carrier and a lead, and then the conductive strip is bonded to the chip carrier and the lead. SMT process requires lower cost than wire bonding processes.
A conductive strip may be bonded to more than two dice or leads to save more bonding wires.
A conductive strip is stronger than a bonding wire, and thus lowers the possibility of being broken.
A conductive strip may easily replace bonding wires to carry greater current no matter in single-chip packages and multi-chip packages.
The inventive method can be used together with conventional wire bonding processes, in which convention bonding wires are for small current conducting, and conductive strips are for greater current conducting.
The portions of a chip carrier for dice to be attached thereon may be electrically connected to each other, for example in the case of a metal chip carrier; or they may be electrically insulated from each other, for example in the case of a ceramic or plastic chip carrier.
As shown in the above embodiments, a conductive strip for electronic package structure and method according to the present invention may have various sizes and shapes based on their applications and may be bonded to several dice. In addition, in the above embodiments, although it is shown that the dice to be bonded by a conductive strip in an electronic package structure and method according to the present invention are attached on a same chip carrier, dice attached on different chip carriers may be bonded by a conductive strip in some applications according to the present invention.
Preferably, the conductive strip used in an electronic package structure and method according to the present invention is a metal, such as copper, silver and lead.
While the present invention has been described in conjunction with preferred embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and scope thereof as set forth in the appended claims.
Claims
1. An electronic package structure comprising:
- a first die having a first bonding pad thereon;
- a second die having a second bonding pad thereon; and
- a conductive strip bonded to the first bonding pad and the second bonding pad.
2. The electronic package structure of claim 1, further comprising a chip carrier carrying the first die and the second die.
3. The electronic package structure of claim 2, wherein the chip carrier comprises:
- a first portion having the first die thereon; and
- a second portion having the second die thereon;
- wherein the first portion and the second portion are electrically connected to each other.
4. The electronic package structure of claim 2, wherein the chip carrier comprises:
- a first portion having the first die thereon; and
- a second portion having the second die thereon;
- wherein the first portion and the second portion are electrically insulated from each other.
5. The electronic package structure of claim 1, further comprising:
- a third die having a third bonding pad thereon; and
- a bonding wire bonded to the third bonding pad and a fourth bonding pad on the first die.
6. The electronic package structure of claim 5, further comprising a chip carrier carrying the first die, the second die and the third die.
7. The electronic package structure of claim 6, wherein the chip carrier comprises:
- a first portion having the first die thereon;
- a second portion having the second die thereon; and
- a third portion having the third die thereon;
- wherein at least two of the first portion, the second portion and the third portion are electrically connected to each other.
8. The electronic package structure of claim 6, wherein the chip carrier comprises:
- a first portion having the first die thereon;
- a second portion having the second die thereon; and
- a third portion having the third die thereon;
- wherein at least two of the first portion, the second portion and the third portion are electrically insulated from each other.
9. The electronic package structure of claim 1, wherein at least one of the first bonding pad and the second bonding pad has a bump thereon, and the conductive strip is bonded thereon.
10. The electronic package structure of claim 1, wherein the conductive strip is a metal.
11. An electronic package structure comprising:
- a die having a bonding pad thereon;
- a lead of a leadframe; and
- a conductive strip bonded to the bonding pad and the lead.
12. The electronic package structure of claim 11, further comprising a chip carrier of the leadframe carrying the die.
13. The electronic package structure of claim 11, wherein the bonding pad has a bump thereon, and the conductive strip is bonded thereon.
14. The electronic package structure of claim 11, wherein the lead has a bonding material thereon, and the conductive strip is bonded thereon.
15. The electronic package structure of claim 14, wherein the bonding material is a solder.
16. The electronic package structure of claim 14, wherein the bonding material is a conductive glue.
17. The electronic package structure of claim 11, wherein the conductive strip is a metal.
18. An electronic package structure comprising:
- a die having a bonding pad thereon;
- a chip carrier of a leadframe carrying the die;
- a lead of the leadframe; and
- a conductive strip bonded to the lead and the chip carrier.
19. The electronic package structure of claim 18, wherein each of the lead and the chip carrier has a bonding material thereon, and the conductive strip is bonded thereon.
20. The electronic package structure of claim 19, wherein the bonding material is a solder.
21. The electronic package structure of claim 19, wherein the bonding material is a conductive glue.
22. The electronic package structure of claim 18, further comprising a bonding wire bonded to the chip carrier and the lead.
23. The electronic package structure of claim 18, further comprising:
- a second lead of the leadframe; and
- a bonding wire bonded to the second lead and the bonding pad.
24. The electronic package structure of claim 18, wherein the conductive strip is a metal.
25. An electronic package structure comprising:
- a die having a bonding pad thereon;
- a chip carrier of a leadframe carrying the die;
- a first lead of the leadframe;
- a second lead of the leadframe; and
- a conductive strip bonded to the first lead and the second lead.
26. The electronic package structure of claim 25, wherein each of the first lead and the second lead has a bonding material thereon, and the conductive strip is bonded thereon.
27. The electronic package structure of claim 26, wherein the bonding material is a solder.
28. The electronic package structure of claim 26, wherein the bonding material is a conductive glue.
29. The electronic package structure of claim 25, further comprising a bonding wire bonded to the bonding pad and the first lead.
30. An electronic package method comprising the steps of:
- providing two dice, each having a bonding pad thereon; and
- bonding a conductive strip to the two bonding pads.
31. The electronic package method of claim 30, further comprising the step of attaching the two dice on a chip carrier.
32. The electronic package method of claim 30, wherein the step of bonding a conductive strip to the two bonding pads comprises the steps of:
- applying a bonding material on the conductive strip or on the two bonding pads;
- disposing the conductive strip on the two bonding pads with the bonding material therebetween; and
- heat treatment for bonding the conductive strip to the two bonding pads with the bonding material.
33. The electronic package method of claim 32, wherein at least one of the two bonding pads has a bump thereon, and the conductive strip is bonded thereto.
34. The electronic package method of claim 30, further comprising the step of bonding a wire to a third bonding pad on the first die and a fourth bonding pad on a third die.
35. An electronic package method comprising the steps of:
- providing a die having a bonding pad thereon and a lead of a leadframe; and
- bonding a conductive strip to the bonding pad and the lead.
36. The electronic package method of claim 35, further comprising the step of attaching the die on a chip carrier of the leadframe.
37. The electronic package method of claim 35, wherein the step of bonding a conductive strip to the bonding pad and the lead comprises the steps of:
- applying a bonding material on the conductive strip, or on the bonding pad and the lead;
- disposing the conductive strip on the bonding pad and the lead with the bonding material therebetween; and
- heat treatment for bonding the conductive strip to the bonding pad and the lead with the bonding material.
38. The electronic package method of claim 37, wherein the bonding pad has a bump thereon, and the conductive strip is bonded thereon.
39. The electronic package method of claim 35, wherein the step of applying a bonding material on the conductive strip, or on the bonding pad and the lead comprises the step of printing or spotting the bonding material on the conductive strip, or on the bonding pad and the lead.
40. An electronic package method comprising the steps of:
- providing a chip carrier and a lead of a leadframe; and
- bonding a conductive strip to the chip carrier and the lead.
41. The electronic package method of claim 40, wherein the step of bonding a conductive strip to the chip carrier and the lead comprises the steps of:
- applying a bonding material on the conductive strip, or on the chip carrier and the lead;
- disposing the conductive strip on the chip carrier and the lead with the bonding material therebetween; and
- heat treatment for bonding the conductive strip to the chip carrier and the lead.
42. The electronic package method of claim 40, further comprising the step of bonding a wire to the chip carrier and a bonding pad on a die.
43. The electronic package method of claim 40, further comprising the step of bonding a wire to a bonding: pad of a die on the chip carrier and a second lead.
44. An electronic package method comprising the steps of:
- providing two leads of a leadframe; and
- bonding a conductive strip to the two leads.
45. The electronic package method of claim 44, wherein the step of bonding a conductive strip to the two leads comprises the steps of:
- applying a bonding material on the conductive strip or on the two leads;
- disposing the conductive strip on the two leads with the bonding material therebetween; and
- heat treatment for bonding the conductive strip to the two leads.
46. The electronic package method of claim 44, further comprising the step of bonding a wire to the first lead and a bonding pad on a die.
Type: Application
Filed: Feb 12, 2008
Publication Date: Aug 21, 2008
Inventor: Yu-Lin Yang (Zhubei City)
Application Number: 12/068,773
International Classification: H01L 23/48 (20060101); H01L 21/00 (20060101);