Chip scale package and method for manufacturing the same
A chip scale package includes a patterned circuit layer attached to the active surface of a semiconductor chip through an anisotropic conductive adhesive layer such that contact pads on a lower surface of the patterned circuit layer are electrically coupled to corresponding bonding pads on the semiconductor chip. The patterned circuit layer has a plurality of openings formed therein at locations corresponding to the contact pads such that each of the contact pads has a portion exposed from an upper surface of the patterned circuit layer through the corresponding opening. A plurality of metal bumps are respectively disposed in the openings and mounted to the exposed portions of the contact pads for making external electrical connection. The present invention further provides a method for manufacturing the chip scale package at the wafer-level.
1. Field of the Invention
This invention relates to a chip scale package (CSP), and more specifically to a method of making the chip scale package at the wafer level.
2. Description of the Related Art
As electronic devices have become smaller and thinner, the velocity and the complexity of IC chip become higher and higher. Accordingly, a need has arisen for higher package efficiency. Demand for miniaturization is the primary catalyst driving the usage of advanced packages such as chip scale packages (CSP) and flip chips. Both of them greatly reduce the amount of board real estate required when compared to the alternative ball grid array (BGA) and thin small outline package (TSOP). Typically, a CSP is 20 percent larger than the chip itself. The most obvious advantage of CSP is the size of the package; that is, the package is slightly larger than the chip. Another advantage of CSP is that the package facilitates test and burn-in before assembly as an alternative to known good die (KGD) testing. In addition, CSP can combine many of the benefits of surface mount technology (SMT), such as standardization, encapsulation, surface mount, and reworkability, with the benefits of flip chip technology, such as low inductance, high I/O count, and direct thermal path. However, CSP has at least one disadvantage compared to conventional BGA and TSOP, namely, high cost per unit.
SUMMARY OF THE INVENTIONIt is therefore an object of the present invention to provide a low-cost chip scale package.
It is another object of the present invention to provide a low-cost method of manufacturing chip scale packages at the wafer-level.
A chip scale package having features of the present invention generally includes a patterned circuit layer attached to the active surface of a semiconductor chip through an anisotropic conductive adhesive layer such that contact pads on a lower surface of the patterned circuit layer are electrically coupled to corresponding bonding pads on the semiconductor chip. The patterned circuit layer has a plurality of openings formed therein at locations corresponding to the contact pads such that each of the contact pads has a portion exposed from an upper surface of the patterned circuit layer through the corresponding opening. A plurality of metal bumps are respectively disposed in the openings of the patterned circuit layer and mounted to the exposed portions of the contact pads of the patterned circuit layer for making external electrical connection.
The contact pads may be formed at locations corresponding to the bonding pads on the semiconductor chip, and the contact pads of the patterned circuit layer are electrically coupled to the corresponding bonding pads on the semiconductor chip only through conductive particles provided in the anisotropic conductive adhesive layer. Alternatively, the contact pads may be formed as a part of a conductive patterned layer to redistribute the bonding pads 122 into a desired format. The conductive patterned layer may include a plurality of conductive traces each having a first end portion formed at a location corresponding to one of the bonding pads on the semiconductor chip and a second end portion serving as the contact pad, and the contact pads of the patterned circuit layer are electrically coupled to the corresponding bonding pads on the semiconductor chip only through conductive particles provided in the anisotropic conductive adhesive layer and the conductive traces.
According to another aspect of the invention, there is provided another chip scale package in which the patterned circuit layer has a plurality of contact pads on the lower surface thereof and a plurality of solder pads on the upper surface thereof wherein the contact pads of the patterned circuit layer are electrically coupled to corresponding bonding pads on the semiconductor chip only through the conductive particles provided in the anisotropic conductive adhesive layer, and the metal bumps are respectively mounted to the solder pads of the patterned circuit layer for making external electrical connection.
The chip-sized packages of the present invention can be mass produced easily at the wafer-level thereby significantly reducing the manufacturing cost. Specifically, the method for manufacturing chip scale packages at the wafer-level comprises steps of: (a) forming an anisotropic conductive adhesive layer onto the active surface of the wafer; (b) attaching a patterned circuit layer including a plurality of contact pads onto the wafer through the anisotropic conductive adhesive layer such that the contact pads are electrically coupled to corresponding bonding pads on the semiconductor chip; (c) forming a plurality of metal bumps in the openings and mounted to the contact pads; and (d) conducting a cutting step to obtain individual chip scale packages. The metal bumps may be formed by a solder-ball placing step and a reflowing step. Alternatively, the metal bumps may be formed by a solder paste stencil printing step and a reflowing step.
BRIEF DESCRIPTION OF THE DRAWINGSThese and other features, aspects, and advantages of the present invention will be more fully understood by reading the following detailed description of the preferred embodiment, with reference made to the accompanying drawings as follows:
FIGS. 1 to 6 illustrate in cross-section major steps of fabrication of chip scale packages at the wafer-level according to one embodiment of the present invention;
FIGS. 10 to 11 illustrate in cross-section major steps of fabrication of chip scale packages at the wafer-level according to another embodiment of the present invention;
FIGS. 12 to 14 illustrate in cross-section major steps of fabrication of a patterned circuit layer of a chip scale package (CSP) according to one embodiment of the present invention; and
FIGS. 15 to 16 illustrate in cross-section major steps of fabrication of a patterned circuit layer of a chip scale package (CSP) according to another embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to
Referring to
Specifically, the patterned circuit layer 110 of
Alternatively, the patterned circuit layer 110 of
It could be understood that the anisotropic conductive adhesive may be thermosetting or thermoplastic. Thermal plastic anisotropic adhesives are heated to soften for using and then cooled for curing. Thermal setting anisotropic adhesives require heat curing at temperatures from 100° C.-300° C. for from several minutes to an hour or more.
Referring to
Thereafter, the assembly shown in
Finally, referring to
The chip-sized packages of the present invention can be mass produced easily at the wafer-level thereby significantly reducing the manufacturing cost.
Although the invention has been explained in relation to its preferred embodiments, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.
Claims
1. A chip scale package comprising:
- a semiconductor chip having a plurality of bonding pads formed on an active surface thereof;
- a patterned circuit layer having a plurality of contact pads on a lower surface thereof and a plurality of openings formed therein at locations corresponding to the contact pads such that each of the contact pads has a portion exposed from an upper surface of the patterned circuit layer through the corresponding opening;
- the lower surface of patterned circuit layer attached to the active surface of the semiconductor chip through an anisotropic conductive adhesive layer such that the contact pads of the patterned circuit layer are electrically coupled to the corresponding bonding pads on the semiconductor chip; and
- a plurality of metal bumps respectively disposed in the openings of the patterned circuit layer and mounted to the exposed portions of the contact pads of the patterned circuit layer for making external electrical connection.
2. The chip scale package as claimed in claim 1, wherein the contact pads are formed at locations corresponding to the bonding pads on the semiconductor chip.
3. The chip scale package as claimed in claim 2, wherein the anisotropic conductive adhesive layer is formed from an adhesive filled with a plurality of conductive particles, and the contact pads of the patterned circuit layer are electrically coupled to the corresponding bonding pads on the semiconductor chip only through the conductive particles.
4. The chip scale package as claimed in claim 1, wherein the patterned circuit layer includes a plurality of conductive traces each having a first end portion formed at a location corresponding to one of the bonding pads on the semiconductor chip and a second end portion serving as the contact pad.
5. The chip scale package as claimed in claim 4, wherein the anisotropic conductive adhesive layer is formed from an adhesive filled with a plurality of conductive particles, and the contact pads of the patterned circuit layer are electrically coupled to the corresponding bonding pads on the semiconductor chip only through the conductive particles and the conductive traces.
6. A chip scale package comprising:
- a semiconductor chip having a plurality of bonding pads formed on an active surface thereof;
- a patterned circuit layer having opposing upper and upper surfaces, the patterned circuit layer having a plurality of contact pads on the lower surface thereof and a plurality of solder pads on the upper surface thereof wherein the contact pads are electrically coupled to the corresponding solder pads;
- the lower surface of patterned circuit layer attached to the active surface of the semiconductor chip through an anisotropic conductive adhesive layer having a plurality of conductive particles such that the contact pads of the patterned circuit layer are electrically coupled to the corresponding bonding pads on the semiconductor chip only through the conductive particles; and
- a plurality of metal bumps respectively mounted to the solder pads of the patterned circuit layer for making external electrical connection.
7. A method for manufacturing chip scale packages at the wafer-level, the method comprising steps of:
- providing a tape circuit including a plurality of contact pads on a lower surface of a tape;
- providing a wafer including a plurality of semiconductor chips wherein each semiconductor chip has a plurality of bonding pads on an active surface thereof;
- forming an anisotropic conductive adhesive layer onto the active surface of the wafer;
- attaching the tape circuit onto the wafer through the anisotropic conductive adhesive layer to form a tape-circuit/wafer assembly such that the contact pads are electrically coupled to the corresponding bonding pads on the semiconductor chip;
- removing the tape from the tape-circuit/wafer assembly and exposing the contact pads;
- forming an insulating layer over the tape-circuit/wafer assembly and patterning the insulating layer to form a plurality of openings at locations corresponding to the contact pads after the tape being removed;
- forming a plurality of metal bumps in the openings of the insulating layer and mounted to the contact pads; and
- conducting a cutting step to obtain individual chip scale packages.
8. The method as claimed in claim 7, wherein the contact pads are formed at locations corresponding to the bonding pads on the semiconductor chip.
9. The method as claimed in claim 8, wherein the anisotropic conductive adhesive layer is formed from an adhesive filled with a plurality of conductive particles, and the contact pads of the tape circuit are electrically coupled to the corresponding bonding pads on the semiconductor chip only through the conductive particles.
10. The method as claimed in claim 7, wherein the tape circuit includes a plurality of conductive traces each having a first end portion formed at a location corresponding to one of the bonding pads on the semiconductor chip and a second end portion serving as the contact pad.
11. The method as claimed in claim 10, wherein the anisotropic conductive adhesive layer is formed from an adhesive filled with a plurality of conductive particles, and the contact pads of the tape circuit are electrically coupled to the corresponding bonding pads on the semiconductor chip only through the conductive particles and the conductive traces.
12. The method as claimed in claim 7, wherein the metal bumps are formed by placing a plurality of solder balls in the openings of the insulating layer and then conducting a reflowing step.
13. The method as claimed in claim 7, wherein the metal bumps are formed by a solder paste stencil printing step and a reflowing step.
14. A method for manufacturing chip scale packages at the wafer-level, the method comprising steps of:
- providing a patterned circuit layer with a tape attached thereon, the patterned circuit layer including a plurality of contact pads on a lower surface thereof and a plurality of openings formed therein at locations corresponding to the contact pads such that each of the contact pads has a portion exposed from an upper surface of the patterned circuit layer through the corresponding opening;
- providing a wafer including a plurality of semiconductor chips wherein each semiconductor chip has a plurality of bonding pads on an active surface thereof;
- forming an anisotropic conductive adhesive layer onto the active surface of the wafer;
- removing the tape from the patterned circuit layer and attaching the patterned circuit layer onto the wafer through the anisotropic conductive adhesive layer such that the contact pads of the patterned circuit layer are electrically coupled to the corresponding bonding pads on the semiconductor chip;
- forming a plurality of metal bumps in the openings of the patterned circuit layer and mounted to the exposed portions of the contact pads of the patterned circuit layer; and
- conducting a cutting step to obtain individual chip scale packages.
15. The method as claimed in claim 14, wherein the contact pads are formed at locations corresponding to the bonding pads on the semiconductor chip.
16. The method as claimed in claim 15, wherein the anisotropic conductive adhesive layer is formed from an adhesive filled with a plurality of conductive particles, and the contact pads of the patterned circuit layer are electrically coupled to the corresponding bonding pads on the semiconductor chip only through the conductive particles.
17. The method as claimed in claim 14, wherein the patterned circuit layer includes a plurality of conductive traces each having a first end portion formed at a location corresponding to one of the bonding pads on the semiconductor chip and a second end portion serving as the contact pad.
18. The method as claimed in claim 17, wherein the anisotropic conductive adhesive layer is formed from an adhesive filled with a plurality of conductive particles, and the contact pads of the patterned circuit layer are electrically coupled to the corresponding bonding pads on the semiconductor chip only through the conductive particles and the conductive traces.
19. The method as claimed in claim 14, wherein the metal bumps are formed by placing a plurality of solder balls in the openings of the patterned circuit layer and then conducting a reflowing step.
20. The method as claimed in claim 7, wherein the metal bumps are formed by a solder paste stencil printing step and a reflowing step.
21. A method for manufacturing chip scale packages at the wafer-level, comprising steps of:
- providing a patterned circuit layer including a plurality of contact pads on the lower surface of the patterned circuit layer and a plurality of solder pads on the upper surface of the patterned circuit layer wherein the contact pads are electrically coupled to the corresponding solder pads;
- providing a wafer including a plurality of semiconductor chips wherein each semiconductor chip has a plurality of bonding pads on an active surface thereof;
- forming an anisotropic conductive adhesive layer having a plurality of conductive particles onto the active surface of the wafer;
- attaching the patterned circuit layer onto the wafer through the anisotropic conductive adhesive layer such that the contact pads of the patterned circuit layer are electrically coupled to the corresponding bonding pads on the semiconductor chip only through the conductive particles;
- mounting a plurality of metal bumps to the solder pads of the patterned circuit layer; and
- conducting a cutting step to obtain individual chip scale packages.
22. The method as claimed in claim 21, wherein the metal bumps are formed by a solder-ball placing step and a reflowing step.
23. The method as claimed in claim 21, wherein the metal bumps are formed by a solder paste stencil printing step and a reflowing step.
International Classification: H01L 23/34 (20060101);