TW530398B - Method for manufacturing bumps of chip scale package (CSP) - Google Patents

Abstract

A method for manufacturing bumps of chip scale package (CSP) is provided. A mold is installed in front of a nozzle of injection device, the mold forms a plurality of holes. A semi-molten metal is filled inside the injection device. Then, the injection device injects the semi-molten metal to a plurality of contact pads of a provided substrate, so a plurality of bumps are formed on the contact pads by injection molding.

Description

530398

[Field of the Invention] 'It is particularly related to the formation of a bump on a substrate. The present invention relates to a method for forming bumps, a method for directly sealing several bumps at a wafer size by injection molding. [Previous technology] The "chip size package" [called Scale Package by csp] is not larger than the area of the chip-half of the point-five times the size of the chip = body, ,, "", because the size of the package structure is reduced to Close to the chip, and said the advantages of miniaturized packaging 'Therefore, high-density packaging technologies include bare chip packaging (b ^ e chip) and flip-chip packaging (fHp chip), most of which use bumps for electrical connection between the chip and the substrate In U.S. Patent No. 5,906, 3 1 2 "Flip-Chip Bumps and Manufacturing Method", a method for manufacturing flip-chip bumps is disclosed, in which wires are bonded by wire bonding and thermal ultrasound (Therm — sonic bonding) to connect to the pads of the wafer to form a bumps with a tip. The wafer's pads are surrounded by passivation layers to protect the wafer and A conductive layer (such as nickel or metal) is formed on the surface of the block by means of an electric clock or the like. The conductive layer has high electrical and thermal characteristics, and can also reduce contact resistances for chip-on-chip Join to one The substrate, however, the bumps formed by wire bonding directly on the wafer (or wafer) are formed by wire bonding one by one using a wire bonder. The bumps cannot be produced in large quantities at one time, so the production efficiency needs to be improved. 530398 Description of the Invention (2) [Objective and Summary of the Invention] The main object of the present invention is to provide a bump forming method for a wafer-size package, which uses an injection molding method to directly form a plurality of bumps on a substrate of a wafer-size package to make the bumps The block manufacturing process is highly productive. A second object of the present invention is to provide a bump forming method for a wafer size package, which uses an injection molding method to form a plurality of bumps on a substrate of the wafer size package. The bumps may have a tip, which is advantageous. Face bonding. According to the method for forming bumps of a wafer-size package according to the present invention, a die is provided at the front end of a discharge port of an f-out device, and the die has a plurality of die holes. The molten metal is ejected from a discharge port of the injection device to a plurality of lead pads of a substrate to form a plurality of bumps. [Detailed description of the invention] Please refer to the attached drawings. The present invention will enumerate the following embodiment descriptions: In the first specific embodiment of the present invention, the first diagram is a cross-sectional view of a bump forming method for a chip size package The bumps are formed on the US by a metal injection molding (MIM) method, and the manufacturing method is described in detail below. ^ As shown in FIG. 1, a substrate 10 is prepared. The substrate 10 may be ceramic, printed circuit board (PCB), wafer or wafer, etc. In this embodiment, the substrate 1 0 is a wafer, and a plurality of contact pads 11 (contact pads) are formed on the surface for forming bumps.

530398

Main == Xingzhi injection device 2〇 (injecti0 “-i-), which includes U thermal furnace 21, feeding screw 22, discharge hopper, hopper 25 (ij two (one), in which口 = 具 = quality ^ metal or ceramics, etc., which has a plurality of die attachment η ΐ The opening of the hole 28 is approximately equal to the guide of the substrate 10 ί ϊ α! Ί And the end of the die hole 28 has a larger diameter In order to facilitate the introduction of f shot soil half: molten metal, and semi-molten metal (semii〇iten) is filled from the feed hopper 24 to the inside of the hot smelter of the injection device 20, and r "continuously heating the inside of the injection device 20" Semi-molten metal to keep its melting degree (such as the melting temperature of tin is about 2000t and the melting temperature of gold is about 1064t or more). The semi-molten metal is composed of a metal powder and a binder (or a combination of two molecules) Agent), the metal powder can be gold, tin, tin-lead alloy or tin-copper alloy, etc., and the injection device 20 is used to promote the feeding screw 22 to promote the feed screw 22 to force the semi-molten metal to be discharged from the material. The die at the front end of the mouth 23 is shot in a die hole 28 of 27. ^ Position the substrate 10 in front of the die 27 with the positioning device 30, and The positioning device 30 can control the substrate 10 to move back and forth, so that the plurality of mold holes 28 of the mold 27 correspond to the conductive pads of the substrate 10. Preferably, the substrate 10 and the mold 27 have a distance therebetween. The distance is approximately equal to the height / degree of the required bump 丨 2. As shown in FIG. 2, the semi-molten metal is shot from the discharge port 23 of the injection device 20 and passed through the die hole 28 of the mold 27. The semi-molten metal is welded to the lead pad 11 of the substrate 10, and the bump 12 is formed after the semi-molten metal is cooled and solidified. If necessary, the semi-molten metal can be cooled to 530398 before the semi-molten metal is cooled and solidified.

V. Description of the invention (4) The positioning device 30 moves the substrate 1 0 ′ or the injection device 2 0, so that the bump 12 has a tip 1 3 ′ and has appropriate elasticity to facilitate surface mounting. ) In addition, preferably, the substrate 10 is placed in a temperature-controlled closed space, or a cooling device (not shown) is provided in the positioning device 30, and when the projection 12 is formed by injection, It can make the semi-melted alloy rapidly solidify. ~

After that, as shown in FIG. 3, the bumps produced by the above process are used as green compacts, and the bumps 12 are debinding to remove the previously mixed adhesive, and The substrate 10 with bumps 12 (such as wafers or wafers) can be used for surface bonding, and if necessary, sintering (such as atmospheric sintering, gas sintering or hot pressing sintering, etc.) Etc.) to make the structures of the bumps 12 denser and have a grabbing degree (more than 95%), high mechanical properties and high electroplatability, and when injection molding, the bumps 12 can have a tip 13. Another layer of highly conductive metal such as gold, nickel, or palladium can be plated on the surface of the bump 12, and the :: f surface can be used to increase the electrical contact. For this reason, the injection molding method can form a plurality of substrates on the substrate 10 at a time. The bump 12 can save a lot of subsequent ^ = steps, so that the process of the bump has high mass production, so by injection

In this way, the bumps can be produced efficiently, and the labor, time, and cost can be saved in the process. Therefore, the scope of protection of the invention is determined by the scope of the attached patent application. The following are the scope of the invention: Anyone who is familiar with this technology, without departing from the spirit and scope of the invention, belongs to the scope of protection of the invention.

530398 Brief description of the drawings [Illustration of the drawings] Figure 1: According to a specific embodiment of the present invention, a sectional view of a bump formed on a wafer-size package substrate by injection molding; and Figure 2: According to the present invention In a specific embodiment, the positioning device and the injection device are moved so that the bump has a tip cross-sectional view; and FIG. 3 is a cross-sectional view of the bump formed on the substrate of the wafer-size package according to the injection molding method of the present invention. [Illustration of drawing number] 10 base plate 11 lead pad 12 bump 13 tip 20 injection device 21 hot melting furnace 22 feeding screw 23 discharge opening 24 feeding hopper 25 motivator 26 heater 27 mold 28 mold L 30 positioning device

8th tribute

Claims (1)

530398 A method for forming a bump of a skirt is to set a mold. The mold is filled with a semi-molten gold port to be ejected to a substrate, and a wafer size is enclosed at the front end of a discharge port. A dagger is set in the injection device. A plurality of bumps are formed. , It is a injection molding system with a plurality of molds, the semi-molten metal is a plurality of lead pads, 2, as in the scope of the application for the first patent of a H p bucket private strong ancient, soil ^ ^ ^ The semi-molded metal (Semi-molten metal) in the injection device of the Japanese film size package described in Japanese is encapsulated by a metal agent. Bu ~ Le ,,, Mouth 3, Bump forming method of wafer size package as described in item 2 of the patent application scope, wherein the metal powder is gold, tin, tin-lead alloy or tin-copper alloy. Method for forming bumps of a wafer size package described in item 1 of the scope of patent application 'wherein one end of the die hole of the mold has a larger diameter. Method for forming bumps of a wafer size package described in item 1 of the scope of patent application Wherein, the substrate is positioned by a positioning device, which controls the substrate to move forward and backward. The method for forming a bump of a wafer-size package as described in item 1 of the Shen-Jin patent scope, wherein the bump is moved during the injection molding of the bump. Injection device to The bump is provided with a tip. The bump forming method for a wafer-size package as described in item 1 of the patent application scope, wherein the substrate is a ceramic circuit board, a printed circuit board, a wafer, or a wafer.