Silver paste die bonding and dispensing pressure claws and equipment

Abstract

The present invention discloses a pressure claw and equipment for dispensing silver paste for solid crystal dispensing. The pressure claw includes a pressure claw body for pressing a lead frame and a baffle connected to the pressure claw body. The baffle extends to block the dispensing area of ​​the lead frame and is provided with a through dispensing hole. The dispensing hole is penetrated by a needle for dispensing silver paste. This arrangement plays a corresponding preventive role in dust control of the product, reduces the frequency of needle cleaning, reduces the number of times the needle is disassembled and assembled, reduces the waste of silver paste in the needle, ensures the dispensing speed, improves the production efficiency of the dispensing process, and simultaneously improves the yield rate of the product and ensures the qualified rate of the product.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor packaging, and in particular to a pressure claw and equipment for silver paste die bonding and dispensing. Background Art

[0002] like Figure 1 、 Figure 2 As shown, during the semiconductor packaging process, the lead frame 2' needs to be pressed by the pressure claw 1', and then the silver paste is applied by the needle 3' to perform die bonding (die bonding) of low-power die. As the number of dispensing increases, silver paste is easily accumulated at the dispensing site of the needle 3'. This makes it easy for the silver paste adhering to the dispensing site of the needle 3' during the dispensing process to splash. The splashed silver paste particles will fall onto the surface of the chip or the surface of the lead frame 2', seriously affecting the performance of the product. Therefore, it is necessary to prevent the silver paste particles from splashing onto the surface of the chip or the lead frame 2' to ensure product reliability.

[0003] The traditional method of preventing silver paste from splashing is simply to regularly clean the needle 3' and slow down the device's dispensing speed. This method has the following problems: the needle 3' needs to be cleaned frequently, which is time-consuming and laborious; the slowdown in dispensing speed seriously affects the device's production capacity, resulting in a mismatch between the dispensing process and the production capacity of other processes; and the conveyor track on which the chip and lead frame 2' are located is an open track, which cannot block the splashing silver paste particles generated by the device during dispensing. It also cannot prevent foreign matter in the air and oil stains generated by equipment maintenance and lubrication from splashing onto the chip or lead frame 2' surface, and thus cannot effectively prevent dust from being sprayed onto the product. Summary of the Invention

[0004] The invention discloses a pressure claw and equipment for silver paste solid crystal dispensing, which are used to solve the problems in the prior art of frequent needle cleaning, slow dispensing speed and low product yield.

[0005] In order to solve the above problems, the present invention adopts the following technical solutions:

[0006] A pressure claw for silver paste die-bonding and dispensing is provided, comprising a pressure claw body for pressing a lead frame and a baffle connected to the pressure claw body, wherein the baffle extends to cover the dispensing area of ​​the lead frame and is provided with a through dispensing hole, and a needle for dispensing silver paste is passed through the dispensing hole.

[0007] Optionally, the baffle is provided with an annular boss surrounding the dispensing hole.

[0008] Optionally, the back of the baffle is fixed to the front of the pressure claw body, and the annular boss is arranged on the back of the baffle, wherein the back of the baffle faces the lead frame and the front of the pressure claw body faces away from the lead frame.

[0009] Optionally, a fixing plate connected to the pressure claw body and used to fix the pressure claw body is further included, and the baffle is fixedly connected to the fixing plate.

[0010] Optionally, the pressure claw body is provided with one.

[0011] Optionally, the pressure claw body is a tungsten steel pressure claw body.

[0012] Optionally, the front side of the baffle is provided with a black coating.

[0013] A silver paste solid crystal dispensing device is also provided, comprising the pressure claw described in any one of the above, a syringe for holding silver paste, a bracket for fixing the syringe, and a needle connected to the syringe.

[0014] Optionally, the syringe is a translucent polyethylene syringe.

[0015] Optionally, the needle is a stainless steel needle.

[0016] Optionally, the ratio of the outer diameter of the needle to the aperture of the dispensing hole is 1:1.2-1.3.

[0017] The technical solution adopted by the present invention can achieve the following beneficial effects:

[0018] The baffle can prevent silver paste particles from splashing onto the surface of the chip or lead frame, and at the same time prevent oil and foreign matter in the air from splashing onto the surface of the chip or lead frame, thereby playing a corresponding preventive role in the dust control of the product, reducing the frequency of needle cleaning, reducing the number of times the needle is disassembled and assembled, reducing the waste of silver paste in the needle, ensuring the dispensing speed, improving the production efficiency of the dispensing process, and at the same time improving the product yield and ensuring the product qualification rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments, which constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0020] Figure 1 It is a structural diagram of the silver paste bonding and dispensing equipment disclosed in the prior art;

[0021] Figure 2 for Figure 1 A magnified view of part A;

[0022] Figure 3 This is a schematic structural diagram of a silver paste die-bonding and dispensing device disclosed in an embodiment of the present invention;

[0023] Figure 4 for Figure 3 A magnified view of part B;

[0024] Figure 5 This is a schematic diagram of the back structure of the pressure claw in the first direction disclosed in an embodiment of the present invention;

[0025] Figure 6 This is a schematic diagram of the back structure of the pressure claw in the second direction disclosed in an embodiment of the present invention;

[0026] Figure 7 A schematic structural diagram of a lead frame disclosed in an embodiment of the present invention.

[0027] Among them, Figure 1-7 Specifically include the following figure marks:

[0028] Press claw-1'; Lead frame-2'; Needle head-3';

[0029] Pressing claw 1; lead frame 2; needle 3; syringe 4; bracket 5; pressing claw body 11; baffle 12; dispensing hole 121; annular boss 122; fixing plate 13; dispensing area 21. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] The technical solutions disclosed in various embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0032] like Figure 3-Figure 6 As shown, the pressure claw 1 of the present invention is used during the dispensing of silver paste for bonding, realizing semi-enclosed dispensing of silver paste for bonding. The pressure claw 1 includes a pressure claw body 11 and a baffle 12. The pressure claw body 11 is used to press the lead frame 2 to prevent the lead frame 2 from moving during dispensing. The baffle 12 is connected to the pressure claw body 11 and extends to the dispensing area 21 ( Figure 7 As shown), a through dispensing hole 121 is provided on the baffle 12, so that the needle 3 passes through the dispensing hole 121 to dispense silver paste and complete the dispensing process. It should be noted that the degree to which the baffle 12 blocks the dispensing area 21 can be specifically set according to needs.

[0033] By setting up in the above manner, the chip and lead frame 2 located around the needle 3 can be shielded by the baffle 12 to form a semi-closed transmission track. When the needle 3 gradually accumulates silver paste at the tip of the needle 3 due to long-term use, and the silver paste at the tip of the needle 3 splashes around during the movement of the needle 3, the baffle 12 blocks the silver paste particles from splashing onto the surface of the chip or lead frame 2, and at the same time blocks oil and foreign matter in the air from splashing onto the surface of the chip or lead frame 2, thereby playing a corresponding preventive role in the dust control of the product, reducing the cleaning frequency of the needle 3, reducing the number of times the needle 3 is disassembled and assembled, reducing the waste of silver paste in the needle 3, ensuring the dispensing speed, improving the production efficiency of the dispensing process, and at the same time improving the yield of the product and ensuring the qualified rate of the product.

[0034] Baffle 12 can be provided with an annular boss 122 surrounding glue dispensing hole 121. The wall groove formed by the wall of annular boss 122 and the wall of glue dispensing hole 121 prevents silver paste from splashing. This arrangement ensures the height of the wall groove, further reducing the possibility of silver paste particles splashing onto the surface of the chip or lead frame 2. Furthermore, while maintaining the height of the wall groove, the thickness of baffle 12 at other locations is reduced, thereby reducing the overall weight of baffle 12 and reducing the risk of baffle 12 sinking and contacting the lead frame 2.

[0035] Specifically, the baffle 12 can be in the form of a rectangular plate, with the back of the baffle 12 fixed to the front of the claw body 11. That is, the back of the baffle 12 is in contact with the front of the claw body 11, with the back of the baffle 12 facing the lead frame 2 and the front of the claw body 11 facing away from the lead frame 2. In this case, an annular boss 122 is provided on the back of the baffle 12. This arrangement provides a simple structure and facilitates installation. It keeps the baffle 12 away from the lead frame 2, reducing the risk of contact between the baffle 12 and the lead frame 2. Furthermore, the annular boss 122 reduces the gap between the baffle 12 and the lead frame 2, thereby reducing the possibility of silver paste splashing through the gap between the baffle 12 and the lead frame 2.

[0036] It should be noted that the annular boss 122 should be set reasonably so as not to cause product contact, that is, the annular boss 122 should be recessed into the pressing claw body 11. In other words, when the pressing claw body 11 presses the lead frame 2, a gap is left between the annular boss 122 (the side facing the lead frame 2) and the lead frame 2 in a direction perpendicular to the lead frame 2.

[0037] To further reduce the risk of the baffle 12 sinking, the baffle 12 can also be connected to the fixing plate 13 of the pressure claw 1. The fixing plate 13 is arranged perpendicular to the pressure claw body 11 at one end of the pressure claw body 11, and the pressure claw body 11 is pressed onto the lead frame 2 through the fixing plate 13.

[0038] At this time, because the baffle 12, the fixed plate 13, and the pressure claw body 11 are connected to each other, the pressure claw body 11 is substantially non-deformed by the baffle 12 and the fixed plate 13. This allows only one pressure claw body 11 to be provided, reducing costs and facilitating assembly. The pressure claw body 11 can be in the form of an elongated strip and positioned near an edge of the baffle 12. The end of the pressure claw body 11 away from the fixed plate 13 may or may not protrude from the baffle 12.

[0039] Furthermore, the material of the pressing claw body 11 can be tungsten steel. Tungsten steel is tough and hard, and is not easily worn or deformed. When the pressing claw body 11 presses the lead frame 2, it will not cause the lead frame 2 to float or be scratched, thereby improving the pressing effect of the pressing claw 1 and ensuring the firmness of the pressing claw 1.

[0040] A dispensing hole 121 is provided on the baffle 12, and is located approximately in the middle of the baffle 12. Each time a dispensing operation is completed, the pressing jaw 1 is lifted away from the lead frame 2 via the fixing plate 13, and the lead frame 2 is then moved until the next dispensing position on the lead frame 2 is aligned with the dispensing hole 121. The pressing jaw 1 is then moved downward to the pressing jaw body 11 to press against the lead frame 2, and then dispensing is continued.

[0041] The diameter of dispensing hole 121 can be slightly larger than the outer diameter of needle 3 (for ease of understanding, the outer diameter of needle 3 refers to the outer diameter of the needle 3's discharge point, or the outer diameter of the needle 3's tip) and the pad size of lead frame 2. In one example, the ratio of the outer diameter of needle 3 to the diameter of dispensing hole 121 is 1:1.2-1.3 (inclusive). This configuration does not affect the upward and downward movement of needle 3 or the identification of pad position during dispensing.

[0042] In addition, a black coating may be provided on the front surface of the baffle 12 or even the entire baffle 12 , that is, the baffle 12 is treated with black. This color does not reflect light and will not cause differences in pad position recognition.

[0043] The silver paste solid crystal dispensing device of the present invention includes the above-mentioned pressure claw 1, a syringe 4 for holding silver paste, a bracket 5 for fixing the syringe 4, and a needle 3 connected to the syringe 4. In the silver paste solid crystal dispensing device, the baffle 12 can prevent silver paste particles from splashing onto the surface of the chip or lead frame 2, and at the same time prevent oil and foreign matter in the air from splashing onto the surface of the chip or lead frame 2, thereby playing a corresponding preventive role in the dust control of the product, thereby reducing the cleaning frequency of the needle 3, reducing the number of times the needle 3 is disassembled and assembled, reducing the waste of silver paste in the needle 3, ensuring the dispensing speed, improving the production efficiency of the dispensing process, and at the same time improving the product yield and ensuring the product qualification rate.

[0044] The main function of syringe 4 is to load the silver paste material. It is fixed to the bracket 5. An air pipe is added above the syringe 4. Under certain pressure and time, the silver paste is discharged. The material of syringe 4 can be translucent polyethylene. The translucent polyethylene syringe 4 will not crack or deform under the ultra-low temperature storage conditions of silver paste. At the same time, the translucent state makes it easy to observe the amount of silver paste used.

[0045] The main function of the needle 3 is to connect to the syringe 4, allowing the silver paste to be discharged in a fixed shape. The syringe 4 can be made of stainless steel, specifically 316 stainless steel. The stainless steel needle 3 facilitates the discharge of the silver paste and the cleaning of the needle 3 when it is contaminated, improving cleaning efficiency and saving cleaning solution. During cleaning, the stainless steel needle 3, which is contaminated with silver paste, is placed in a polyethylene beaker, which is filled with an alcohol solution and cleaned under the action of ultrasonic vibrations of a certain power.

[0046] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A pressure claw for silver paste die bonding and dispensing, characterized in that: It includes a pressing claw body for pressing the lead frame and a baffle connected to the pressing claw body, wherein the baffle extends to cover the glue dispensing area of ​​the lead frame and is provided with a through glue dispensing hole, and the glue dispensing hole is penetrated by a needle for dispensing silver paste; The baffle is provided with an annular boss surrounding the dispensing hole; The back of the baffle is fixed to the front of the pressing claw body, and the annular boss is arranged on the back of the baffle, wherein the back of the baffle faces the lead frame, and the front of the pressing claw body faces away from the lead frame, and the annular boss is recessed in the pressing claw body so that when the pressing claw body presses the lead frame, a gap is left between the annular boss and the lead frame; It also includes a fixing plate connected to the pressing claw body and used to fix the pressing claw body, and the baffle is fixedly connected to the fixing plate; The pressure claw body is a tungsten steel pressure claw body.

2. The silver paste die bonding and dispensing pressure claw according to claim 1, characterized in that: The pressing claw body is provided with one.

3. The silver paste die bonding and dispensing pressure claw according to any one of claims 1-2, characterized in that: The front side of the baffle is provided with a black coating.

4. A silver paste bonding and dispensing device, characterized in that: The invention comprises a pressing claw according to any one of claims 1 to 3, a syringe for containing silver paste, a bracket for fixing the syringe, and a needle connected to the syringe.

5. The silver paste bonding and dispensing equipment according to claim 4, characterized in that: The syringe is a translucent polyethylene syringe.

6. The silver paste bonding and dispensing equipment according to claim 4, characterized in that: The needle is a stainless steel needle.

7. The silver paste bonding and dispensing equipment according to claim 4, characterized in that: The ratio of the outer diameter of the needle to the aperture of the dispensing hole is 1:1.2-1.3.

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