TW535269B - Electrical device with elastic bumps and method for making the same - Google Patents

Abstract

An electrical device with elastic bumps is disclosed. The electrical device includes a plurality of elastic bumps form on contact pads of a substrate. Each elastic bump has an elastic body forms a through hole. The through hole connects the corresponding contact pad from the upper surface of elastic body. The conductive paste is filled in the through hole for electrically connecting the corresponding contact pads. Thus, the elastic bumps of electrical device are no collapsing at surface mounting to improve electrical connection and absorb thermal stress on mounting interface.

Description

535269 V. Description of the Invention (l) [Field of the Invention] The present invention relates to an electronic device with elastic bumps and a method for manufacturing the same, and particularly relates to a conductive adhesive filled in the through-holes of the elastic blocks of the elastic bumps. To improve the electrical connection and thermal stress absorption of electronic devices. [Prior art] The conventional electrical connection methods of electronic devices include wire bonding, flip chip mounting, and the like. The flip chip bonding method is to combine the chip with bumps. To the substrate,

Because the thermal expansion coefficient (CTE) of the wafer and the substrate does not match, thermal stress is generated at the bonding interface. Therefore, it is known to form an underfilling material between the wafer and the substrate to absorb the thermal stress. Miniaturization and high density, the distance between the solder joints of the wafer is reduced, and the bump return is also reduced, which increases the difficulty of filling material formation. Because of the known bump material, tin, lead, gold and other metals are used. Without elasticity, the thermal stress generated at the bonding interface cannot be effectively absorbed.

As shown in FIG. 7, in US Patent No. 6, 028, 357, "Semiconductor Device in which Solder Bumps are Covered with Cylinders," a semiconductor device is disclosed in which a conductive film is formed on the surface of the circuit substrate 1. 2. The conductive film 2 is covered with a solder resist layer 3, which has an opening so that the electrode 4 of the conductive film 2: is exposed, and a columnar conductive adhesive 5 is formed on the electrode 4 by printing. = Conductive conductive paste 5 contains copper metal powder, and the columnar conductive paste 5 is heated to cure. \: A solder bump 7A is formed on the opening of the solder resist layer 3, and the solder bump = reflow 1 (re f 1 ow) Form a hemispherical shape to cover the columnar guide "^ 5, because the material of the solder bump 7A is a tin-lead alloy, etc., does not have

535269 V. Description of the invention (2) Electronic skirts with elastic bumps on wafers and circuit substrates, which have through-holes in the absorption bond, and are conductively glued together, so the elastic bumps are cracked to ensure that the electronics have elastic bumps. The electronic assembly of the block has a through hole in the absorption bonding boundary and the conductive glue is connected in a shape, so the electronic package with the elastic bump of the elastic bump (underf i11i ng) has an elastic block, and each elastic conductive glue is in the through hole. When it is inside, the electro-adhesive can be easily filled in the elastic bonding, and it is not easy to produce the collapse interface.

Excellent elasticity, therefore, 1 β P 袓 ^^ This cannot effectively absorb the thermal stress between the production 1 and Zhike bump 7A. [Objective and Summary of the Invention] The main purpose of the present invention is to provide a sub-device; the pedestal is less t. The odor bumps are spring-shaped into the through holes for the c-block system. The formation of electrical bumps with good elasticity of bumps & i makes it difficult to install external electrical connections during surface bonding. Set, one! It is to provide-a kind of ^ ^ elastic bump system with elastic & 0: W force, each elastic block system is formed; in the k-hole, as the elastic system has good elasticity, 铕 er brother < Ye Zhuang step. The purpose of forming filling materials is to provide a variety of elastic bumps. Electronic blocks are formed with through holes and exhaust holes. When the exhaust holes are formed, they can be discharged from the through holes. The gas makes the through hole of the conductive block, so the elastic bump is cracked on the surface, which can not only improve the electrical connection, but also effectively thermal stress. Therefore, another object of the present invention is to provide a method for forming a sacrificial device on a substrate, a sacrificial layer and an electrically insulating elastic layer, and then

535269 V. Description of the invention (3) " ---- Etching to form a plurality of elastic blocks with through holes, and then remove the sacrificial layer to make the elastic blocks have vent holes, and fill the through holes with conductive glue. Therefore, a large number of elastic bumps can be fabricated on a substrate. f The electronic device with elastic bumps of the present invention includes a substrate and a plurality of elastic bumps, wherein the substrate may be a wafer, a wafer, a printed circuit board, a ceramic substrate or a film, and a plurality of elastic bumps. It is formed on the conductive pad of the substrate. Each elastic bump is composed of an elastic block. The elastic block is an electrically insulating and highly elastic polymer organic substance. The elastic block has a through hole. The through hole is formed by the elastic block. The top surface of the elastic block is connected to the corresponding conductive pad. Preferably, the elastic block further forms at least one vent hole connected to the through hole. When a conductive adhesive is applied to the top surface of the elastic block, the conductive adhesive is distributed on the top surface of the elastic block due to capillary action. The gas system in the through-hole and the through-hole is discharged through the exhaust hole, so that the conductive glue is filled in the through-hole and is electrically connected to the corresponding conductive pad. Tian Qiu, according to the method for manufacturing an electronic device according to the present invention, includes the steps of: lifting, a board, such as a wafer, a wafer, a printed circuit board, a ceramic substrate, or a thin film. The surface of the substrate has a plurality of guides. Pads; preferably, sacrificial layers can be formed on the pads of the substrate, these sacrificial layers do not completely cover the conductive pads, and then are formed on the surface of the substrate by printing, spin-coating or adhesive film bonding techniques An electrically insulating elastic layer covering the conductive pads and the sacrificial layer; the elastic layer is etched to form a plurality of elastic blocks corresponding to the conductive pads, and the elastic blocks are formed with through holes, which are formed by the elastic blocks. The top surface is connected to the corresponding lead ^, and then the sacrificial layer is removed, so that the elastic block is formed with an exhaust hole that communicates with the through hole; a conductive adhesive is applied to the top surface of the elastic block. Phenomenon flows in the through hole, and the gas in the through hole is discharged through the exhaust hole, so that the guide

535269

The electric glue is filled in the through hole, and is electrically coupled to the corresponding lead pad. [Detailed description of the invention] Please refer to the attached drawings. The present invention will enumerate the following embodiment descriptions ... According to a specific embodiment of the present invention, As shown in FIG. 6, the electronic device with elastic bumps includes a substrate 10 and a plurality of elastic bumps 20. The substrate 10 may be a chip, a wafer, or a printed circuit board ( printed circuit board (PCB), ceramic substrate, or thin film

In the example, the substrate 10 is a wafer of a memory, a micro processor or a microcontroller. 'A plurality of contact pads 12 (contact pads)' such as an aluminum pad (A1 pad) or copper are formed on the surface 11 thereof. Cu pad and so on. A plurality of elastic bumps 20 are formed on the conductive pads 2 of the substrate 10, which include elastic blocks 21 and conductive adhesive 24. The elastic blocks 21 are formed on the conductive pads 12 of the substrate 10. And cover the corresponding conductive pads 12, and the elastic block 21 is a kind of organic polymer with electrical insulation and high elasticity, such as polyimide, benezo cyclobutene , Polyacrylates, rubber or si 1 i cone, etc., each elastic block 21 has a through hole 22, the through hole 22 is connected from the top surface of the elastic block 21 to the corresponding The contact pad 12 is preferably formed with at least one row of air holes 23 in the elastic block 21, and the exhaust hole 23 is connected to the through hole 22 and extends radially to the outside of the elastic block 21 so that the through hole 22 An air-conducting channel is formed with the exhaust hole 23 for discharging the gas in the through-hole 22, and a conductive glue 24 is formed on the top surface of each elastic block 21 and the through-hole 22, and the material of the conductive glue 24 Contains gold (Au), silver

Page 8 535269 V. Description of the invention (5) (Ag), copper (Cu) and other conductive metal powders of the thermosetting conductive paste (conductive paste), and the conductive paste 24 formed in the through hole 22 is electrically connected to the corresponding Conductive pads 12, when the electronic device must be surface bonded to an external circuit board, the conductive adhesive 2 on the top surface of the elastic block 2 1 can improve the electrical bonding area, and the conductive adhesive 24 in the through hole 22 is elastic. Block 2 1 is wrapped around 'so the elastic bump 20 is not easy to crack, so that the electronic device has a good electrical connection' and the elastic block 2 1 of the elastic bump 20 has excellent elasticity, which is bonded to the surface of the electronic device. After the external circuit board, the thermal stress caused by the thermal expansion coefficient (CTE) mismatch of the bonding interface can be absorbed by the elastic bumps 21 of the elastic bumps 20 to prevent the mechanical formation of the elastic bumps 2 at the bonding interface. Sexual thermal fatigue. The manufacturing method of the electronic device with elastic bumps of the present invention is described in detail as follows:

First, as shown in FIG. 1, a substrate is provided, such as a wafer, a wafer, a printed circuit board, a ceramic substrate, or a thin film. The surface ij of the substrate is formed with a plurality of conductive pads 12. These lead pads 12 and 2 can be arranged in a grid array, center or peripherally, and a surface of the substrate 10 is covered with a layer of photoresist. The photolithography technology is used to make the lead pads 12 on the substrate 10 A sacrifice layer 26 (sacrifécia) is formed to form a photoresist. The sacrifice layer 26 does not completely cover the conductive pad 12 and is an easily removable material. The lead pad 12 is extended to the outside of the lead pad 12, and then printed (pr ^ η η ng), spin coating, or fum adhering is applied to the substrate 1 0. The surface 11 forms an electrically insulating elastic layer 25, and the elastic

Page 9 535269 V. Description of the invention (6) The sexual layer 2 5 covers the conductive pads 12 and the sacrificial layer 26. Then, as shown in FIG. 2, the elastic layer 25 is etched by using lithography imaging and dry / wet etching techniques to form a plurality of elastic blocks 21 corresponding to the conductive pads 12, and these elastic blocks 21 are covered. Corresponding to the contact pads 12, and through-holes 22 are formed. Preferably, these through-holes 22 are formed at the same time during the etching process, or laser holes are drilled on the elastic block 21 after the money carving is completed. The through hole 2 2 is formed from the top surface of the elastic block 21 to the corresponding lead pad 12. Then, as shown in FIG. 3, the sacrificial layer 26 is removed, so that the elastic block 21 is formed with a plurality of exhaust holes 23. The exhaust holes 23 formed by the sacrificial layer 26 are connected to the through hole 22, The through hole 22 and the exhaust hole 23 form an air guide channel. Preferably, the exhaust hole 2 3 is closely attached to the elastic conductive pad 12 to facilitate the exhaust of the through hole 2 2. These exhaust holes 2 3 are The communication through holes 22 are connected in parallel. The bottom of block 21 is connected to the corresponding gas, as shown in Figure 4, which extends radially to the elastic block 2 1 and then as shown in Figure 5, screen printing (screen pririting) or note injection A technique such as applying a thermosetting conductive glue 2 4 on the top surface of each elastic block 2 1 'The conductive glue 2 4 has liquid fluidity, flows into the through-hole 22 due to capillarity, and flows on the conductive glue 24 At the same time, the gas in the through hole 22 will be exhausted through the exhaust hole 23, so that the conductive glue 24 can be filled in the through hole 22. Preferably, the conductive glue 24 is also partially filled in the exhaust hole 2 3 . ; L Finally, as shown in FIG. 6, the conductive adhesive 24 is thermally cured. The main 24 is formed on the top surface of each elastic block 21, the through hole 22 and the exhaust gas are electrically connected to the corresponding lead. Pad 12, because the elastic bump 20 is elastic

535269 V. Description of the invention (7) Block 21 is used as the main body, and conductive glue 24 is filled in the through hole 22 of the elastic block 21, even though the lead pads 12 of the substrate 10 (such as a wafer) have a smaller pitch or a higher bonding interface height. Low, only the height of the elastic block 21 can be determined in advance to effectively control the formation height of the elastic bump 20, so for high-density or miniaturized packages, such as Chip Scale Package (CSP), the elastic bump 20 can also provide good electrical contact. When the electronic device is surface bonded, the conductive adhesive 24 can improve the electrical bonding area, and the conductive adhesive 24 in the through hole 22 is surrounded by the elastic block 21, Making the elastic bump 20 not easy to crack when the surfaces are bonded, not only can improve the electrical connection, but also can effectively absorb the thermal stress generated at the junction interface. Therefore, the scope of protection of the present invention shall be determined by the scope of the appended patent application. Any changes and modifications made by those skilled in the art without departing from the spirit of the present invention ^ belong to the protection of the present invention. Fan

535269 Simple illustration of the drawings [Illustration of the drawings] Picture 1 · According to the book Picture 2: According to the plan view Picture 3 According to the book Picture 4 According to the book Picture 5 According to the book Picture 6 According to the book Picture 7 Semiconductor device [Illustration of drawing number], a sectional view of a substrate forming an elastic layer and a sacrificial layer; a sectional view of a substrate forming a plurality of elastic blocks with through holes, and a sectional view of a substrate with the sacrificial layer removed ' ^ Sectional view of a substrate coated with an electrically conductive layer, a sectional view of an electronic device with elastic bumps; and No. 6, 028, 357 "Cross section view of a solder bump covered with a cylinder. 1 Circuit board 4 Electrode 10 Substrate 11 surface 2 0 elastic bump 21 elastic block 24 conductive adhesive 2 conductive film 5 conductive adhesive 12 lead pad 22 through hole 2 5 elastic layer 3 solder mask 7A solder bump 2 3 exhaust hole 2 6 sacrificial layer

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Claims (1)

535269 6. Scope of patent application [Scope of patent application] 1. An electronic device with elastic bumps includes: a substrate, and the surface of the substrate has a plurality of conductive pads; the elastic block is formed on the substrate. On the pad, the elastic block has a through hole and at least one exhaust hole, wherein the through hole is communicated from the top surface of the elastic block to the corresponding conductive pad, and the exhaust hole is connected to the through hole for the through hole. The gas is exhausted; and the conductive adhesive is formed in the through hole of the corresponding elastic block and is electrically connected to the corresponding conductive pad. 2. The electronic device with elastic bumps as described in item 1 of the scope of patent application, wherein the exhaust holes of the elastic blocks extend radially to the outside of the elastic blocks. 3. The electronic device with elastic bumps as described in item 1 of the scope of the patent application, wherein the exhaust holes are closely attached to the bottom of the elastic block and communicate with the corresponding conductive pads, so as to facilitate the discharge of the holes in the through holes. gas. 4. The electronic device with elastic bumps as described in item 1 of the scope of patent application, wherein the conductive adhesive is formed in the exhaust hole of the corresponding elastic block. 5. The electronic device with elastic bumps as described in item 1 of the scope of the patent application, wherein the conductive adhesive is a thermosetting conductive adhesive containing gold, silver, and copper conductive metal powder. 6. The electronic device with elastic bumps as described in item 1 of the scope of patent application, wherein the elastic blocks are conductive pads covering the substrate. 7. The electronic device with elastic bumps as described in item 1 of the scope of the patent application, wherein the elastic blocks are high-molecular organic materials which are electrically insulated. 535269 6. Scope of patent application 8. Electronic devices with elastic bumps as described in item 7 of the scope of patent applications, wherein the elastic blocks are polyimide, phenylcyclobutene, polypropylene, rubber or Silicone. 9. The electronic device with elastic bumps as described in item 7 of the scope of patent application, wherein the substrate is a wafer, a wafer, a printed circuit board, a ceramic substrate or a thin film. 10. An electronic device with elastic bumps, comprising: a substrate, a surface of the substrate having a plurality of contact pads; an elastic block is formed on a conductive pad of the substrate, and the elastic block has a through hole The through hole is connected to the corresponding conductive pad from the top surface of the elastic block; and the conductive adhesive is formed in the through hole of the corresponding elastic block and is electrically connected to the corresponding conductive pad. U. The electronic j = with elastic bumps as described in item 10 of the scope of the patent application, wherein the conductive adhesive is a thermosetting conductive adhesive L containing gold, silver, and copper conductive metal powder. 12 Miles as described in the scope of the patent application No. 10 "Electronics with elastic bumps" Eight middle 1 2 3 4 5 5 These elastic blocks are polyimide, phenylcyclobutene, polyacrylate, rubber or silicone . 1 3 The electronic device with elastic bumps as described in the 10th member of the patent scope 2 The substrates are sold as wafers, wafers, printed circuit boards, ceramics 3 rolls or films. 4 14. A method for manufacturing an electronic device, the steps of which include: 5 9 for a substrate, the surface of the substrate has a plurality of conductive pads; 535269 Layer: The elastic layer of ίίίίΐ is covered with the conductive pads on the substrate. The elastic layer covers the conductive pads; the elastic layer is etched to form a plurality of elastic pads corresponding to the conductive pads, and the elastic blocks are formed. There are through holes, which are reversely connected from the top surface of the elastic block to the corresponding conductive pads; and through holes formed with conductive glue on the elastic blocks are electrically connected to the corresponding conductive pads. The method for manufacturing an electronic device according to item 14, which further includes the step of forming a sacrificial layer on the conductive pad of the substrate after providing a substrate, and the sacrificial layer extends from the corresponding conductive pad to the outside of the conductive pad. 16. According to the method for manufacturing an electronic device described in item 15 of the scope of the patent application, which further includes the step of #etching the elastic layer, removing the sacrificial layer, so that the elastic block forms at least one vent hole. The exhaust hole formed by the sacrificial layer is connected to the through hole. 17. The manufacturing method of the electronic device described in item 14 of the scope of the patent application, wherein the method of forming the elastic layer is printing, spin coating or adhesive film sticking. 18, if applying for special The method for manufacturing an electronic device described in item 14 of the scope, wherein the method for forming the conductive adhesive is screen printing or injecting. 1 9. The method for manufacturing the electronic device described in item 14 of the scope of patent application, the other The steps included are heat-curing conductive adhesives. 20. The method for manufacturing an electronic device as described in item 14 of the scope of the patent application, wherein in the step of providing a substrate, the substrate is a wafer, 535269 6. Scope of patent application Wafer, printed circuit board, ceramic substrate or film 0 Page 16