Tool clamp for pressed silver sintering process

Abstract

A work fixture for a pressed silver sintering process relates to the technical field of semiconductor processing, and comprises an upper cover plate, a pressing block carrying disc and a lead frame carrying disc which are sequentially arranged from top to bottom, a plurality of lead frame positioning pins for positioning a chip lead frame are arranged on the lead frame carrying disc; the lead frame carrying disc and the pressing block carrying disc are respectively provided with pressing plate positioning through holes which are opposite to each other up and down. A plurality of vertically-through pressing block positioning holes are formed in the pressing block carrying disc, and a pressing block capable of sliding up and down is arranged in each pressing block positioning hole; the pressing block carrying disc and the upper cover plate are respectively provided with cover plate positioning through holes which are right opposite to each other up and down. A plurality of pressing block grooves capable of being matched with the pressing blocks are formed in the lower surface of the upper cover plate, the pressing block grooves correspond to the pressing blocks in a one-to-one mode, a vertically-through pressing block top hole is formed in the groove top of each pressing block groove, and a pressing piece capable of tightly jacking the pressing blocks is arranged in each pressing block top hole. The clamp provided by the utility model is used for a pressed silver sintering process.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor processing technology, and in particular to a tooling fixture for a pressure silver sintering process. Background Technology

[0002] Silver sintering technology, also known as low-temperature interconnect technology, is a novel lead-free chip interconnect technology that can achieve high-temperature resistant (>700℃) and high thermal conductivity (~240 W / m·K) sintered silver chip interconnect interfaces under low-temperature (<250℃) conditions. Silver sintering technology has the following advantages:

[0003] The sintered bonding layer is composed of silver, which has excellent electrical and thermal conductivity.

[0004] ②Since silver has a melting point as high as 961℃, typical fatigue effects will not occur in soft solder joints with melting points below 300℃, resulting in extremely high reliability.

[0005] ③ The sintering material used has a sintering temperature similar to that of traditional soft solder;

[0006] ④ The sintered material does not contain lead and is an environmentally friendly material.

[0007] Compared to solder alloys, silver sintering technology can more effectively improve the operating temperature and lifespan of power devices. Currently, silver sintering technology has received widespread attention in the field of high-temperature power electronics, and is particularly suitable as an interconnect interface material for wide-bandgap semiconductor power devices such as high-temperature SiC devices.

[0008] Silver sintering processes can be divided into pressure sintering and pressureless sintering. The difference between the two is that pressure sintering applies pressure to the silver layer during the sintering process. Compared to pressureless sintering, pressure sintering can form a denser sintered layer, resulting in better performance and reliability.

[0009] The steps for silver sintering are as follows:

[0010] ① Print silver paste onto the metal surface of the object to be sintered using a stencil;

[0011] ② The silver paste is pre-baked to reduce the gaps between the silver particles by heating;

[0012] ③ Use a surface mount component soldering head to apply temperature and pressure to the chip and mount the chip onto the silver paste surface;

[0013] ④ Place the object to be sintered into a silver sintering equipment with a mold. The mold is used to precisely position the chip. The pressure applied to the chip surface by the mold is precisely controlled by pressure and temperature sensors. The mold temperature is also controlled and adjusted. Within a reasonable time, a temperature & pressure vs. time curve is set to form a dense sintered layer of silver under the chip.

[0014] Existing silver sintering equipment is expensive and is usually used in the production of high value-added products. However, the demand in the low-to-mid-end market is much greater than that in the high-end market, and the high cost makes it difficult for the silver sintering process to be widely adopted. Utility Model Content

[0015] In view of the defects existing in the prior art, the technical problem to be solved by this utility model is to provide a tooling fixture for pressure silver sintering process that is easy to install and disassemble, facilitates mass production, can replace existing silver sintering equipment for sintering steps, and thus reduces costs.

[0016] In order to solve the above-mentioned technical problems, the present invention provides a tooling fixture for pressurized silver sintering process, characterized in that: it includes an upper cover plate, a pressure block carrier plate and a lead wire frame carrier plate arranged from top to bottom;

[0017] The lead frame carrier is provided with a plurality of lead frame positioning pins for positioning the chip lead frame;

[0018] The lead frame carrier and the pressure block carrier are respectively provided with pressure plate positioning through holes that are directly opposite each other, and multiple sets of pressure plate positioning through holes are provided in pairs.

[0019] The pressure block carrier plate has multiple vertically penetrating pressure block positioning holes, and each pressure block positioning hole contains a pressure block that can slide up and down.

[0020] The pressing plate and the upper cover plate are respectively provided with upper and lower facing cover plate positioning through holes, and multiple sets of cover plate positioning through holes are provided in pairs.

[0021] The lower surface of the upper cover plate is provided with multiple pressure block grooves that can cooperate with the pressure blocks. Each pressure block groove corresponds to a pressure block. The top of each pressure block groove is provided with a pressure block top hole that runs vertically through the groove, and the pressure block top hole contains a pressure-applying component that can press the pressure block tightly.

[0022] Furthermore, the upper surface of the lead frame carrier and the lower surface of the pressure block carrier are respectively formed with mating pressure plate positioning posts and pressure plate positioning grooves, so that the lead frame carrier and the pressure block carrier can be locked to each other in the horizontal direction through the engagement of the pressure plate positioning posts and pressure plate positioning grooves.

[0023] Furthermore, the upper surface of the pressing plate and the lower surface of the upper cover plate are respectively formed with mating cover plate positioning posts and cover plate positioning grooves, so that the pressing plate and the upper cover plate can be locked to each other in the horizontal direction through the engagement of the cover plate positioning posts and cover plate positioning grooves.

[0024] Furthermore, the positioning through hole of the cover plate is a countersunk threaded hole.

[0025] Furthermore, the top hole of the pressure block is a countersunk threaded hole.

[0026] Furthermore, the positioning through hole of the pressure plate is a countersunk threaded hole.

[0027] Furthermore, the pressure-applying component is a stud, and the top hole of the pressure block is a screw hole.

[0028] The tooling fixture provided by this utility model for the pressurized silver sintering process adopts a three-layer separable structure consisting of an upper cover plate, a pressure block carrier plate, and a lead frame carrier plate. The chip installation and removal steps are simple and time-saving. After applying pressure to the chip using the pressure block, sintering is completed in the heating equipment. It can replace the existing silver sintering equipment for the sintering step, thereby reducing costs. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the tooling fixture for the pressure silver sintering process according to an embodiment of the present invention. Detailed Implementation

[0030] The embodiments of this utility model are described in further detail below with reference to the accompanying drawings. However, these embodiments are not intended to limit this utility model. Any similar structures or variations thereof that adopt this utility model should be included in the protection scope of this utility model. The commas in this utility model all indicate the relationship between and.

[0031] like Figure 1 As shown in the figure, the tooling fixture for the pressurized silver sintering process provided by this utility model includes an upper cover plate 1, a pressure block carrier plate 2 and a lead wire frame carrier plate 3 arranged from top to bottom.

[0032] The lead frame carrier 3 is provided with a plurality of lead frame positioning pins 31 for positioning the chip lead frame;

[0033] The lead frame carrier 3 and the pressure block carrier 2 are respectively provided with pressure plate positioning through holes 32 facing each other vertically. Multiple sets of pressure plate positioning through holes 32 are provided in pairs vertically. The upper surface of the lead frame carrier 3 and the lower surface of the pressure block carrier 2 are respectively formed with mating pressure plate positioning posts 331 and pressure plate positioning grooves 332, so that the lead frame carrier 3 and the pressure block carrier 2 can be locked to each other in the horizontal direction through the engagement of the pressure plate positioning posts 331 and pressure plate positioning grooves 332.

[0034] The pressing block carrier plate 2 has multiple pressing block positioning holes 21 that are vertically connected, and each pressing block positioning hole 21 contains a pressing block 22 that can slide vertically.

[0035] The pressing plate carrier 2 and the upper cover plate 1 are respectively provided with upper and lower facing cover plate positioning through holes 23. Multiple sets of cover plate positioning through holes 23 are provided in pairs. The upper surface of the pressing plate carrier 2 and the lower surface of the upper cover plate are respectively formed with mating cover plate positioning posts 241 and cover plate positioning grooves 242, so that the pressing plate carrier 2 and the upper cover plate 1 can be locked to each other in the horizontal direction through the fitting of the cover plate positioning posts 241 and cover plate positioning grooves 242.

[0036] The lower surface of the upper cover plate 1 is provided with a plurality of pressure block grooves 11 that can cooperate with the pressure block. The pressure block grooves 11 correspond one-to-one with the pressure block 22. Each pressure block groove 11 has a pressure block top hole 12 that runs vertically through the top of the groove, and the pressure block top hole 12 is provided with a pressure applying element 13 that can press the pressure block tightly.

[0037] In this embodiment of the utility model, the cover plate positioning through hole 23, the pressure plate positioning through hole 32 and the pressure block top hole 12 are countersunk threaded holes, the pressure application component 13 is a stud, and the pressure block top hole 12 is a threaded hole.

[0038] This utility model embodiment is used in a pressure silver sintering process, and its usage method is as follows:

[0039] First, the chip to be sintered is mounted on the chip lead frame (the chip lead frame is usually a copper frame with positioning holes for matching lead frame positioning pins 31). Then, the chip lead frame is placed on the lead frame carrier 3 and fixed with the lead frame positioning pins 31, so that each chip on the chip lead frame is aligned with the positioning holes 21 of the pressure block. Then, the pressure block carrier 2 and the lead frame carrier 3 are fitted together with the pressure plate positioning pins 331 and the pressure plate positioning grooves 332. Studs are inserted into each set of pressure plate positioning through holes 32 to fix the pressure block carrier 2 and the lead frame carrier 3.

[0040] Then, place the pressure block 22 into the pressure block positioning hole 21, and fit the upper cover plate 1 and the pressure block carrier plate 2 into the cover plate positioning groove 242 through the cover plate positioning post 241. Insert studs into each set of cover plate positioning through holes 23 to fix the upper cover plate 1 and the pressure block carrier plate 2.

[0041] At this time, insert the stud 13 into the top hole 12 of the pressure block, screw the stud 13 until it abuts against the upper surface of the pressure block 22, and apply pressure to the pressure block 22. Use a torque device to apply torque to the stud 13 according to the pressure required for silver sintering chips. After the pressure is applied, put the fixture into the oven equipment for sintering.

Claims

1. A tooling fixture for pressure silver sintering process, characterized in that: It includes, from top to bottom, a top cover plate, a pressure block carrier plate, and a lead wire frame carrier plate; The lead frame carrier is provided with a plurality of lead frame positioning pins for positioning the chip lead frame; The lead frame carrier and the pressure block carrier are respectively provided with pressure plate positioning through holes that are directly opposite each other, and multiple sets of pressure plate positioning through holes are provided in pairs. The pressure block carrier plate has multiple vertically penetrating pressure block positioning holes, and each pressure block positioning hole contains a pressure block that can slide up and down. The pressing plate and the upper cover plate are respectively provided with upper and lower facing cover plate positioning through holes, and multiple sets of cover plate positioning through holes are provided in pairs. The lower surface of the upper cover plate is provided with multiple pressure block grooves that can cooperate with the pressure blocks. Each pressure block groove corresponds to a pressure block. The top of each pressure block groove is provided with a pressure block top hole that runs vertically through the groove, and the pressure block top hole contains a pressure-applying component that can press the pressure block tightly.

2. The tooling fixture for pressure silver sintering process according to claim 1, characterized in that: The upper surface of the lead frame carrier and the lower surface of the pressure block carrier are respectively formed with mating pressure plate positioning posts and pressure plate positioning grooves, so that the lead frame carrier and the pressure block carrier can be locked to each other in the horizontal direction through the engagement of the pressure plate positioning posts and pressure plate positioning grooves.

3. The tooling fixture for pressure silver sintering process according to claim 1, characterized in that: The upper surface of the pressing plate and the lower surface of the upper cover plate are respectively formed with mating cover plate positioning posts and cover plate positioning grooves, so that the pressing plate and the upper cover plate can be locked to each other in the horizontal direction through the engagement of the cover plate positioning posts and cover plate positioning grooves.

4. The tooling fixture for pressure silver sintering process according to claim 1, characterized in that: The positioning through hole of the cover plate is a countersunk threaded hole.

5. The tooling fixture for pressure silver sintering process according to claim 1, characterized in that: The top hole of the pressure block is a countersunk threaded hole.

6. The tooling fixture for pressure silver sintering process according to claim 1, characterized in that: The positioning through hole of the pressure plate is a countersunk threaded hole.

7. The tooling fixture for pressure silver sintering process according to claim 1, characterized in that: The pressure-applying component is a stud, and the top hole of the pressure block is a screw hole.

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