Diode double-screen printing process structure

Abstract

The utility model discloses a diode double-screen printing process structure, which comprises an integral frame, a plurality of screen printing units are arranged on the integral frame in an array mode, and each screen printing unit comprises a first frame and a second frame which are integrated with the integral frame. The first printing area and the second printing area in each screen printing unit form a lower screen printing layer through integrated printing, the third printing area in each screen printing unit forms an upper screen printing layer through integrated printing, and the first end of a connecting piece is welded to the upper portion of a crystal grain through the upper screen printing layer. And a second end of a connecting sheet is welded above the second frame through a lower screen printing layer. According to the scheme, a double-screen printing process of lower-layer screen printing and upper-layer screen printing can be adopted for production of the diode, integrated printing can be carried out by adopting a whole-piece overall frame, the production efficiency is remarkably improved, and a screen printing process route is adopted for upper and lower welding of the chip, so that the problem of cavities generated by welding can be effectively reduced, and the production cost is reduced. And the production quality is obviously improved.

Description

Technical Field

[0001] The utility model relates to the semiconductor packaging industry and the component packaging technology field, in particular to a diode double screen printing process structure, which is mainly applied to applications such as three-phase automotive power transmission systems, fuel, fuel and water pumps, motor control, DC-DC, etc. Background Art

[0002] Power devices and third-generation semiconductors are the current hotspots pursued by semiconductor industry technologies and are one of the fields of advanced semiconductor technologies in the world. With the advent of the power semiconductor era and the continuous demand in the automotive market, more and more power devices are being widely used in electric vehicles. And the components used in vehicles have raised the reliability level of products to a new level, and the reliability is more stringent compared to the requirements of consumer electronics. Therefore, producing power devices that meet the current automotive use is a necessary requirement for automotive customers.

[0003] The process structure of a conventional diode usually includes a frame and each unit on the frame. A die and a connecting piece are welded in each unit. The existing process structure can only meet the requirements of single unit for tin writing or tin pressing and single dispensing operation. Not only the production efficiency is low, but also there are problems such as unstable glue output, offset dispensing position, and easy generation of air bubbles during the dispensing process, and void problems are also likely to occur during welding.

[0004] In view of this, how to solve the problems of low production efficiency and low product quality existing in the process structure of conventional diodes has become the subject to be studied and solved by the utility model. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a diode double screen printing process structure for solving the problems of low production efficiency and low product quality existing in the process structure of conventional diodes.

[0006] To achieve the above purpose, the utility model proposes a diode double screen printing process structure, and the diode double screen printing process structure includes an overall frame, and a plurality of screen printing units are arranged in an array on the overall frame.

[0007] Each of the screen printing units includes a first frame and a second frame that are integrated with the overall frame.

[0008] The upper surfaces of the first frame and the second frame are flush. The upper surface of the first frame has a first printing area, and a recessed portion is provided downward on the upper surface of the second frame. The recessed portion has a second printing area. The first printing area and the second printing area in each of the screen printing units are integrally printed to form a lower screen printing layer.

[0009] Above the first frame, a crystal grain is welded through a lower screen printing layer. The upper surface of the crystal grain has a third printing area. The third printing areas in each of the screen printing units form an upper screen printing layer through integral printing.

[0010] Above the crystal grain, the first end of a connecting piece is welded through the upper screen printing layer. Above the second frame, the second end of the connecting piece is welded through the lower screen printing layer.

[0011] The relevant content of the present utility model is explained as follows:

[0012] 1. In the above technical solution of the present utility model, through research on problems such as low production efficiency and low product quality existing in the process structure of conventional diodes, a double screen printing process structure for diodes is innovatively developed and designed. In the present utility model, aiming at the problem that the existing process structure can only meet the single unit for tin writing or tin pressing and single dispensing operation, the double screen printing process structure for diodes is designed as an overall frame including multiple screen printing units, and each of the screen printing units includes a first frame and a second frame integrated with the overall frame. The upper surface of the first frame has a first printing area. A recess is provided downward on the upper surface of the second frame. The recess has a second printing area. A lower screen printing layer is formed through integral printing in the first printing area and the second printing area. The crystal grain is arranged above the first printing area of the first frame, and a third printing area is provided on the upper surface of the crystal grain to form an upper screen printing layer. Then, the connecting piece is welded to the upper screen printing layer of the crystal grain and the lower screen printing layer of the second frame, thereby forming an effective and reliable connection. Through the above design, a double screen printing process structure for diodes mainly composed of the upper screen printing layer on the first printing area and the second printing area, and the upper screen printing layer on the third printing area is formed. With this structure, the production of the diode can adopt a double screen printing process of lower screen printing and upper screen printing, and the integral frame of the whole piece can be used for integral printing, so that the production efficiency is significantly improved. Moreover, the upper and lower welding of the chip both adopt the screen printing process route, which can effectively reduce the void problem generated by welding, and the production quality is significantly improved.

[0013] 2. In the above technical solution, in each of the screen printing units, a sealing part is covered and filled on the first frame, the second frame, the crystal grain, and the connecting piece. The sealing part is epoxy resin to effectively protect the internal crystal grain and connecting piece of the diode.

[0014] 3. In the above technical solution, through holes for filling epoxy resin are provided at the part where the connecting piece is connected to the upper chip and in the middle part of the connecting piece. This is used to further improve the bonding strength between the crystal grain, the connecting piece and the epoxy resin on the diode, and further avoid the occurrence of delamination phenomenon.

[0015] 4. In the above technical solution, the middle part of the connecting piece is a bending part, and a double through-hole is arranged in the bending part. The double through-hole design further improves the bonding strength.

[0016] 5. In the above technical solution, the area of the upper surface of the first frame is larger than the area of the first printing area of the first frame, so as to prevent the solder paste brushed on the first printing area from overflowing.

[0017] 6. In the above technical solution, the thickness range of the lower screen printing layer is 0.06 - 0.1 mm, and the thickness range of the upper screen printing layer is 0.06 - 0.08 mm. The setting of this screen printing size can better control the welding thickness of the solder paste, reduce the large stress displacement inside the chip. At the same time, compared with the traditional welding process, the setting of this screen printing size has higher accuracy and better welding flatness.

[0018] 7. In the above technical solution, the depth range of the concave part is 0.05 - 0.1 mm, and the width dimension is 1.5 - 2.5 times the thickness of the connecting piece. The design of this dimension is such that the solder paste for screen printing falls on this concave part, and at the same time, the tail of the connecting piece can be limited here. During welding, large offsets are not likely to occur and can be better controlled within the specifications. In addition, this design can better increase the welding area between the tail of the connecting piece and the second printing area by using the solder paste, and improve the welding force between them.

[0019] 8. In the present utility model, unless otherwise clearly specified and defined, terms such as "installation", "connection", "linkage", "fixation" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium. It can be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0020] 9. In the present utility model, the orientation or positional relationship indicated by terms such as "upper", "lower", "bottom", "inner", "outer", etc. is the orientation or positional assembly relationship based on the orientation or position shown in the drawings. It is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to this application.

[0021] 10. In addition, in the description of the present utility model, it should be noted that if terms such as "first", "second", etc. are used to limit components in this article, those skilled in the art should be aware that the use of terms such as "first", "second", etc. is only for the convenience of describing the present utility model and simplifying the description. Without additional declaration, the above terms have no special meaning.

[0022] Due to the application of the above solution, the present utility model has the following advantages and effects compared with the prior art:

[0023] In the present utility model, the diode double-screen printing process structure is designed as an integral frame including a plurality of screen printing units. Each of the screen printing units includes a first frame and a second frame integrated with the integral frame. The upper surface of the first frame has a first printing area. A recessed portion is provided downward on the upper surface of the second frame, and the recessed portion has a second printing area. A lower screen printing layer is formed by integral printing in the first printing area and the second printing area. The crystal grains are arranged above the first printing area of the first frame, and a third printing area is provided on the upper surface of the crystal grains to form an upper screen printing layer. Then, connecting pieces are welded to the upper screen printing layer of the crystal grains and the lower screen printing layer of the second frame, thereby forming an effective and reliable connection. Through the above design, a diode double-screen printing process structure mainly composed of the upper screen printing layer on the first printing area and the second printing area, and the upper screen printing layer on the third printing area is formed. With this structure, the production of the diode can adopt the double-screen printing process of lower screen printing and upper screen printing, and the integral frame of the whole sheet can be used for integral printing, so that the production efficiency is significantly improved. Moreover, the upper and lower welding of the chip both adopt the screen printing process route, which can effectively reduce the void problem generated by welding, and the production quality is significantly improved. Description of the Drawings

[0024] Figure 1 It is a schematic diagram of the overall structure of the diode double-screen printing process structure in the embodiment of the present utility model;

[0025] Figure 2 In the embodiment of the present utility model Figure 1 Partial enlarged schematic diagram.

[0026] The parts in the above drawings are represented as follows:

[0027] 1 Integral frame

[0028] 2 Screen printing unit

[0029] 3 First frame

[0030] 4 Second frame

[0031] 5 Recessed portion

[0032] 6 First printing area

[0033] 7 Second printing area

[0034] 8 Lower screen printing layer

[0035] 9 Crystal grain

[0036] 10 Third printing area

[0037] 11 Upper screen printing layer

[0038] 12 Connecting piece

[0039] 13 Bending section

[0040] 14 Through Holes

[0041] 15 Sealing part. DETAILED DESCRIPTION

[0042] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0043] The utility model embodiment discloses a diode double screen printing process structure 100, such as Figure 1 , Figure 2 As shown, the diode double screen printing process structure comprises an overall frame 1, on which a plurality of screen printing units 2 are arranged in an array;

[0044] Each of the screen printing units 2 includes a first frame 3 and a second frame 4 which are integrated with the overall frame 1;

[0045] The upper surfaces of the first frame 3 and the second frame 4 are flush with each other. The upper surface of the first frame 3 has a first printing area 6. A recessed portion 5 is provided downwardly on the upper surface of the second frame 4. The recessed portion 5 has a second printing area 7. The first printing area 6 and the second printing area 7 in each of the screen printing units 2 are integrally printed to form a lower screen printing layer 8.

[0046] A crystal grain 9 is welded on the top of the first frame 3 through a lower screen printing layer 8, and the upper surface of the crystal grain 9 has a third printing area 10. The third printing area 10 in each of the screen printing units 2 is integrally printed to form an upper screen printing layer 11.

[0047] A first end of a connecting piece 12 is welded to the top of the crystal grain 9 through an upper screen-printed layer 11 , and a second end of a connecting piece 12 is welded to the top of the second frame 4 through a lower screen-printed layer 8 .

[0048] In the embodiment of the utility model, in each of the screen printing units 2, the first frame 3, the second frame 4, the crystal grain 9, and the connecting piece 12 are covered and filled with a sealing portion 15, and the sealing portion 15 is epoxy resin, so as to effectively protect the crystal grain 9 and the connecting piece 12 inside the diode.

[0049] In the embodiment of the present utility model, through holes 14 for filling epoxy resin are provided at the part where the connecting piece 12 is connected to the upper chip and at the middle part of the connecting piece 12. In this way, the bonding strength between the crystal grains 9, the connecting piece 12 and the epoxy resin on the diode is further improved, and the occurrence of delamination is further avoided.

[0050] In the embodiment of the present utility model, the middle part of the connecting piece 12 is a bending part 13, and double through holes 14 are provided in the bending part 13. The design of the double through holes 14 further improves the bonding strength.

[0051] In the embodiment of the present utility model, the area of the upper surface of the first frame 3 is larger than the area of the first printing area 6 of the first frame 3, so as to prevent the solder paste brushed on the first printing area 6 from overflowing.

[0052] In the embodiment of the present utility model, the thickness range of the lower screen printing layer 8 is 0.06 - 0.1 mm, and the thickness range of the upper screen printing layer 11 is 0.06 - 0.08 mm. The setting of this screen printing size can better control the welding thickness of the solder paste, reduce the large stress displacement inside the chip. At the same time, compared with the traditional welding process, the setting of this screen printing size has higher accuracy and better welding flatness.

[0053] In the embodiment of the present utility model, the depth range of the recessed part 5 is 0.05 - 0.1 mm, and the width dimension is 1.5 - 2.5 times the thickness of the connecting piece 12. The design of this dimension is such that the screen-printed solder paste falls into this recess, and at the same time, the tail of the connecting piece 12 can be limited here, and it is not easy to have large offsets during welding, and it can be better controlled within the specifications. In addition, this design can better increase the welding area between the tail of the connecting piece 12 and the second printing area 7 and improve the welding force therebetween.

[0054] Through the implementation of the embodiments of the present utility model, through the research on the problems of low production efficiency and low product quality existing in the process structure of conventional diodes, a diode double-screen printing process structure is innovatively developed and designed. In the present utility model, aiming at the problem that the existing process structure can only meet the requirements of single-unit tin writing or tin pressing and single dispensing operation, the diode double-screen printing process structure is designed as an overall frame 1 including a plurality of screen printing units 2. And each of the screen printing units 2 includes a first frame 3 and a second frame 4 integrated with the overall frame 1. The upper surface of the first frame 3 has a first printing area 6. A recess 5 is provided downward on the upper surface of the second frame 4. The recess 5 has a second printing area 7. A lower screen printing layer 8 is formed by integral printing in the first printing area 6 and the second printing area 7. And the die 9 is arranged above the first printing area 6 of the first frame 3, and a third printing area 10 is provided on the upper surface of the die 9 to form an upper screen printing layer 11. Then, the connecting piece 12 is welded on the upper screen printing layer 11 of the die 9 and the lower screen printing layer 8 of the second frame 4, so as to form an effective and reliable connection. Through the above design, a diode double-screen printing process structure mainly composed of the upper screen printing layer 11 on the first printing area 6 and the second printing area 7 and the upper screen printing layer 11 on the third printing area 10 is formed. With this structure, the production of the diode can adopt the double-screen printing process of lower screen printing and upper screen printing, and the integral frame 1 of the whole sheet can be used for integral printing, so that the production efficiency is significantly improved. And the upper and lower welding of the chip both adopt the screen printing process route, which can effectively reduce the void problem generated by welding, and the production quality is significantly improved.

[0055] Next, the technical solution of the present utility model will be further described with a more specific detailed embodiment.

[0056] In the diode double-screen printing process structure proposed in this detailed embodiment, it includes an overall frame 1. A plurality of screen printing units 2 are arranged in an array on the overall frame 1. Each of the screen printing units 2 includes a first frame 3 and a second frame 4 integrated with the overall frame 1. The die 9 is welded above the first frame 3. The connecting piece 12 welds the die 9 and the second frame 4. In each of the screen printing units 2, a sealing part 15 is covered and filled on the first frame 3, the second frame 4, the die 9 and the connecting piece 12. The sealing part 15 is epoxy resin.

[0057] In this detailed embodiment, the upper surfaces of the first frame 3 and the second frame 4 are flush. The upper surface of the first frame 3 has a first printing area 6. A recess 5 is provided downward on the upper surface of the second frame 4. The recess 5 has a second printing area 7. The first printing area 6 and the second printing area 7 in each screen printing unit 2 are integrally printed to form a lower screen printing layer 8. The thickness range of the lower screen printing layer 8 is 0.06 - 0.1 mm. Specifically, the thickness of the lower screen printing layer 8 can be selected as 0.06 mm, 0.08 mm, or 0.1 mm. The depth range of the recess 5 is 0.05 - 0.1 mm, and the width dimension is 1.5 - 2.5 times the thickness of the connecting piece 12. Specifically, the depth of the recess 5 is 0.05 mm, 0.07 mm, 0.08 mm, or 0.1 mm, and the width dimension of the recess 5 can be selected as 0.2 mm, 0.3 mm, or 0.45 mm.

[0058] In this detailed embodiment, a die 9 is welded above the first frame 3 through the lower screen printing layer 8. The upper surface of the die 9 has a third printing area 10. The third printing areas 10 in each screen printing unit 2 are integrally printed to form an upper screen printing layer 11. The thickness range of the upper screen printing layer 11 is 0.06 - 0.08 mm. Specifically, the thickness of the upper screen printing layer 11 is 0.06 mm, 0.07 mm, 0.08 mm.

[0059] In this detailed embodiment, through holes 14 for filling epoxy resin are provided at the part where the connecting piece 12 is connected to the upper chip and in the middle part of the connecting piece 12. The middle part of the connecting piece 12 is a bending part 13, and double through holes 14 are provided in the bending part 13.

[0060] The above embodiments are only used to illustrate the technical concept and features of the present invention, and the purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A diode double screen printing process structure, characterized in that: The diode double screen printing process structure includes an overall frame (1), and a plurality of screen printing units (2) are arranged in an array on the overall frame (1); Each of the screen printing units (2) includes a first frame (3) and a second frame (4) integrated with the overall frame (1); The upper surfaces of the first frame (3) and the second frame (4) are flush. The upper surface of the first frame (3) has a first printing area (6). A recessed portion (5) is provided downward on the upper surface of the second frame (4). The recessed portion (5) has a second printing area (7). The first printing area (6) and the second printing area (7) in each of the screen printing units (2) are integrally printed to form a lower screen printing layer (8); A die (9) is welded above the first frame (3) through the lower screen printing layer (8). The upper surface of the die (9) has a third printing area (10). The third printing areas (10) in each of the screen printing units (2) are integrally printed to form an upper screen printing layer (11); The upper end of a connecting piece (12) is welded above the die (9) through the upper screen printing layer (11), and the lower end of the connecting piece (12) is welded above the second frame (4) through the lower screen printing layer (8).

2. The diode double-screen printing process structure according to claim 1, wherein: In each of the screen printing units (2), a sealing portion (15) is covered and filled on the first frame (3), the second frame (4), the die (9), and the connecting piece (12). The sealing portion (15) is epoxy resin.

3. The diode double-screen printing process structure according to claim 1, wherein: Through holes (14) for filling epoxy resin are provided at the part where the connecting piece (12) is connected to the upper chip and at the middle part of the connecting piece (12).

4. The diode double-screen printing process structure according to claim 3, characterized in that: The middle part of the connecting piece (12) is a bent portion (13), and a double through hole (14) is provided in the bent portion (13).

5. The diode double-screen printing process structure according to claim 1, characterized in that: The area of the upper surface of the first frame (3) is larger than the area of the first printing area (6) of the first frame (3).

6. The diode double-screen printing process structure according to claim 1, characterized in that: The thickness range of the lower screen printing layer (8) is 0.06 - 0.1 mm, and the thickness range of the upper screen printing layer (11) is 0.06 - 0.08 mm.

7. The diode double-screen printing process structure according to claim 1, wherein: The depth range of the recessed portion (5) is 0.05 - 0.1 mm, and the width dimension is 1.5 - 2.5 times the thickness of the connecting piece (12).

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