Fixture structure for reflow soldering of thermistor

Abstract

The utility model relates to a fixture structure for reflow soldering of a thermistor, which comprises a copper-clad ceramic substrate limiting frame with a through hole, a thermistor limiting frame and a fixing frame positioning column, and is characterized in that the copper-clad ceramic substrate limiting frame is used for limiting a copper-clad ceramic substrate on a radiator; first positioning through holes corresponding to copper-clad ceramic substrate positioning holes are formed in the periphery of a copper-clad ceramic substrate limiting frame, a thermistor limiting frame is installed on the upper surface of the copper-clad ceramic substrate limiting frame, and a thermistor limiting hole and a second positioning through hole are formed in the thermistor limiting frame. The thermistor limiting hole is matched with the thermistor in shape and is used for limiting the thermistor, and the copper-clad ceramic substrate limiting frame and the thermistor limiting frame are fixed by sequentially penetrating through the first positioning through hole, the second positioning through hole and the positioning hole of the copper-clad ceramic substrate through the fixing frame positioning column.

Description

Technical Field

[0001] The utility model relates to a clamp structure for reflow soldering of a thermistor, belonging to the field of semiconductor module packaging. Background Art

[0002] Most traditional power modules use a two-step reflow method, with separate reflows from chip to DBC and DBC to substrate. The reflow fixture design is relatively simple, and only the soldering process of a single solder needs to be considered. When the fixture is removed after the reflow, abnormal conditions such as DBC corner missing may occur. There are many types and quantities of DBC designs for power modules, and they are prone to shifting during multiple reflows. If the distance between DBCs is too close or they shift too much, it will affect the module performance and the subsequent process steps.

[0003] Therefore, a fixture structure for reflow soldering of thermistor is designed to overcome the above problems. Utility Model Content

[0004] The utility model aims to overcome the shortcomings of the prior art and provide a thermistor reflow soldering fixture structure which has a simple structure, a reliable method and can reduce material and labor costs.

[0005] The utility model is realized through the following technical scheme: a fixture structure for thermistor reflow soldering, the fixture structure is used for clamping a power module of a chip, a copper-clad ceramic substrate, a thermistor and a solder sheet during reflow soldering, the chip, the copper-clad ceramic substrate and the thermistor are soldered to a radiator through the solder sheet, the fixture structure is composed of a copper-clad ceramic substrate limiting frame with through holes, a thermistor limiting frame and a fixed frame positioning column, the copper-clad ceramic substrate limiting frame is used to limit the copper-clad ceramic substrate on the radiator, and the copper-clad ceramic substrate limiting frame is provided with first positioning through holes corresponding to the copper-clad ceramic substrate positioning holes around the first positioning through holes, the copper-clad ceramic substrate limiting frame is provided with first positioning through holes corresponding to the copper-clad ceramic substrate positioning ... A thermistor limiting frame is installed on the upper surface of the copper-clad ceramic substrate limiting frame, and a thermistor limiting hole and a second positioning through hole are respectively arranged on the thermistor limiting frame, wherein the thermistor limiting hole matches the shape of the thermistor and is used to limit the thermistor on the copper-clad ceramic substrate, and the position of the second positioning through hole corresponds to the position of the first positioning through hole, and a fixing frame positioning column is installed in the first positioning through hole and the second positioning through hole, and the fixing frame positioning column passes through the first positioning through hole, the second positioning through hole and the positioning hole of the copper-clad ceramic substrate in sequence, so that the copper-clad ceramic substrate limiting frame and the thermistor limiting frame are connected and positioned with the radiator.

[0006] Preferably, the fixing frame positioning column consists of a slender cylinder and a column seat integrally arranged on the slender cylinder, and the diameter of the column seat is the same as the diameter of the positioning hole on the copper-clad ceramic substrate, the first positioning through hole of the copper-clad ceramic substrate limiting frame, and the second positioning through hole of the thermistor limiting frame, so as to ensure firm fixation.

[0007] Preferably, a reinforcing rib structure is provided in the copper-clad ceramic substrate limiting frame to improve the overall strength of the copper-clad ceramic substrate limiting frame and keep the carrier flat and not easily deformed.

[0008] Preferably, the copper-clad ceramic substrate is composed of an upper surface copper layer, a ceramic layer and a lower surface copper layer arranged in sequence from top to bottom, and the area of ​​the middle ceramic layer is larger than the area of ​​the upper and lower surface copper layers.

[0009] Preferably, the thermistor limiting frame is an "h"-shaped structure rotated 90 degrees counterclockwise, and a first positioning through hole is respectively provided at the upper left corner and the lower right corner of the thermistor limiting frame, and a thermistor limiting hole is provided at the upper right corner near the end.

[0010] Preferably, the thermistor limiting hole of the thermistor limiting frame is a structure that is wide at the top and narrow at the bottom, so as to facilitate clamping of the thermistor.

[0011] Preferably, the side of the heat sink close to the copper-clad ceramic substrate is a welding surface, and the other side is an appearance surface. The welding surface is an arc-shaped surface for releasing stress caused by high-temperature welding.

[0012] The beneficial effects of the utility model are as follows:

[0013] The utility model is mainly equipped with a copper-clad ceramic substrate limit frame, a thermistor limit frame and a fixed frame positioning column. The copper-clad ceramic substrate limit frame and thermistor limit frame suitable for various sizes of copper-clad ceramic substrates can be designed according to actual needs. The copper-clad ceramic substrate limit frame and the thermistor limit frame can realize one-step reflow from the chip to the copper-clad ceramic substrate and from the copper-clad ceramic substrate to the radiator, effectively shortening the welding time and welding cost; the copper-clad ceramic substrates are positioned by isolation pins, and disassembling the fixture after reflow is not likely to cause abnormalities such as missing corners of the insulating substrate ceramic.

[0014] The fixture structure for thermistor reflow soldering designed by the utility model has the characteristics of simple structure, low price, material saving, improved production efficiency and equipment utilization, and can be applied to mass production semiconductor power module soldering process. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the power module and the fixture assembly in the utility model.

[0016] Figure 2 It is a structural schematic diagram of a copper-clad ceramic substrate fixing frame in the utility model.

[0017] Figure 3 It is a structural schematic diagram of the thermistor fixing frame in the utility model.

[0018] Figure 4 It is a schematic diagram of the structure after the fixture structure is assembled and mounted.

[0019] Figure 5 It is a schematic diagram of the welding structure of the medium power module of the utility model. DETAILED DESCRIPTION

[0020] In order to enable ordinary technicians in the field to more clearly understand the purpose, technical solutions and advantages of the utility model, the utility model is further explained below in conjunction with the accompanying drawings and embodiments.

[0021] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", "horizontal" and "vertical" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention. They do not indicate or imply that the device or component referred to must have a specific direction and therefore should not be understood as a limitation on the present invention.

[0022] The utility model will be described in detail below with reference to the accompanying drawings: Figure 1-3 As shown, a fixture structure for reflow soldering of thermistors is used for clamping a power module including a chip, a copper-clad ceramic substrate 3, a thermistor 4 and a soldering piece 2 during reflow soldering. The chip, the copper-clad ceramic substrate 3 and the thermistor 4 are soldered to a heat sink 1 through the soldering piece 2. The fixture structure is composed of a copper-clad ceramic substrate limiting frame 6 with a through hole 8, a thermistor limiting frame 7 and a fixed frame positioning column 5. The copper-clad ceramic substrate limiting frame 6 is used to limit the copper-clad ceramic substrate 3 on the heat sink 1. The copper-clad ceramic substrate limiting frame 6 is provided with first positioning through holes 10 corresponding to the positioning holes 11 of the copper-clad ceramic substrate 3 around it. The upper surface of the copper-clad ceramic substrate limiting frame 6 A thermistor limiting frame 7 is installed, and a thermistor limiting hole 9 and a second positioning through hole 12 are respectively arranged on the thermistor limiting frame 7, wherein the thermistor limiting hole 9 matches the shape of the thermistor 4 and is used to limit the thermistor 4 on the copper-clad ceramic substrate 3, and the position of the second positioning through hole 12 corresponds to the position of the first positioning through hole 10, and a fixing frame positioning column 5 is installed in the first positioning through hole 10 and the second positioning through hole 12, and the fixing frame positioning column 5 passes through the first positioning through hole 10, the second positioning through hole 12 and the positioning hole 11 of the copper-clad ceramic substrate 3 in sequence, so that the copper-clad ceramic substrate limiting frame 6 and the thermistor limiting frame 7 are connected and positioned with the radiator 1.

[0023] The fixing frame positioning column 5 is composed of a slender cylinder and a column seat integrally arranged on the slender cylinder. The diameter of the column seat is the same as the diameter of the positioning hole 11 on the copper-clad ceramic substrate 3, the first positioning through hole 10 of the copper-clad ceramic substrate limiting frame 6 and the second positioning through hole 12 of the thermistor limiting frame 7, so as to ensure firm fixation.

[0024] More specifically, the diameter of the column seat of the fixed frame positioning column 5 is consistent with the diameter of the positioning hole on the substrate, the positioning column is just inserted into it, and a matching gap is designed. The opening diameter of the thermistor limit frame 7 is consistent with the diameter of the slender cylinder of the fixed frame positioning column 5, and a matching gap is designed.

[0025] The copper-clad ceramic substrate limit frame 6 is provided with a reinforcing rib structure to improve the overall strength of the copper-clad ceramic substrate limit frame 6, keep the carrier flat and not easily deformed. The copper-clad ceramic substrate 3 is composed of an upper surface copper layer, a ceramic layer and a lower surface copper layer arranged in sequence from top to bottom, and the area of ​​the middle ceramic layer is larger than the area of ​​the upper and lower surface copper layers.

[0026] The thermistor limit frame 7 is an "h"-shaped structure rotated 90 degrees counterclockwise, and a first positioning through hole 10 is respectively provided at the upper left corner and the lower right corner of the thermistor limit frame 7, and a thermistor limit hole 9 is provided at the upper right corner near the end thereof. The thermistor limit hole 9 of the thermistor limit frame 7 is a structure that is wide at the top and narrow at the bottom, which is convenient for clamping the thermistor 4. The number of positions of the first positioning through hole and the thermistor limit hole and the shape of the thermistor limit frame can be adjusted according to actual conditions without any limitation.

[0027] The side of the heat sink 1 close to the copper-clad ceramic substrate 3 is a welding surface, and the other side is an appearance surface. The welding surface is an arc surface to release the stress caused by high-temperature welding. The surface of the heat sink 1 is plated with a metal material such as nickel, one side is a welding surface, and the other side is an appearance surface; the heat sink 1 needs to have a certain curvature requirement to release the stress caused by high-temperature welding; the welding piece 2 is a solder with tin as the main component; the thermistor 4 is set at both ends for welding.

[0028] The copper-clad ceramic substrate limiting frame 6 also needs to be pre-bent along the curvature of the heat sink 1. The upper surface of the copper-clad ceramic substrate limiting frame 6 is anodized or colored to prevent strong reflections from interfering with the sensor, thereby affecting the recognition effect, and a clamping groove is provided on the copper-clad ceramic substrate limiting frame 6 to facilitate clamping of the copper-clad ceramic substrate 3 (DBC).

[0029] Figure 4 The chip and solder pad 2 are automatically mounted on the assembled semi-finished power module using a mounting machine. Figure 5The soldering piece 2 under the copper-clad ceramic substrate 3 and the soldering piece under the thermistor 4 have the same solder composition, but different sizes and thicknesses. The soldering piece 2 is a solder with tin as the main component.

[0030] The utility model is mainly equipped with a copper-clad ceramic substrate limit frame, a thermistor limit frame and a fixed frame positioning column. The copper-clad ceramic substrate limit frame and thermistor limit frame suitable for various sizes of copper-clad ceramic substrates can be designed according to actual needs. The copper-clad ceramic substrate limit frame and the thermistor limit frame can realize one-step reflow from the chip to the copper-clad ceramic substrate and from the copper-clad ceramic substrate to the radiator, effectively shortening the welding time and welding cost; the copper-clad ceramic substrates are positioned by isolation pins, and disassembling the fixture after reflow is not likely to cause abnormalities such as missing corners of the insulating substrate ceramic.

[0031] The specific embodiments described herein are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present invention shall still be covered by the claims of the present invention.

Claims

1. A fixture structure for reflow soldering of a thermistor, the fixture structure being used for clamping a power module including a chip, a copper-clad ceramic substrate (3), a thermistor (4) and a soldering piece (2) during reflow soldering, wherein the chip, the copper-clad ceramic substrate (3) and the thermistor (4) are soldered to a heat sink (1) via the soldering piece (2), and characterized in that: The clamp structure is composed of a copper-clad ceramic substrate limiting frame (6) with a through hole (8), a thermistor limiting frame (7) and a fixed frame positioning column (5); the copper-clad ceramic substrate limiting frame (6) is used to limit the copper-clad ceramic substrate (3) on the heat sink (1); the copper-clad ceramic substrate limiting frame (6) is provided with first positioning through holes (10) corresponding to the positioning holes (11) of the copper-clad ceramic substrate (3) around it; the thermistor limiting frame (7) is installed on the upper surface of the copper-clad ceramic substrate limiting frame (6); the thermistor limiting frame (7) is provided with thermistor limiting holes (9) and second positioning through holes (12) respectively, wherein The thermistor limiting hole (9) matches the shape of the thermistor (4) and is used to limit the position of the thermistor (4) on the copper-clad ceramic substrate (3); the position of the second positioning through hole (12) corresponds to the position of the first positioning through hole (10); a fixing frame positioning column (5) is installed in the first positioning through hole (10) and the second positioning through hole (12); the fixing frame positioning column (5) passes through the first positioning through hole (10), the second positioning through hole (12) and the positioning hole (11) of the copper-clad ceramic substrate (3) in sequence, so that the copper-clad ceramic substrate limiting frame (6) and the thermistor limiting frame (7) are connected to the heat sink (1) and positioned.

2. The fixture structure for thermistor reflow soldering according to claim 1, characterized in that: The fixing frame positioning column (5) is composed of a slender cylinder and a column seat integrally arranged on the slender cylinder, the column seat has a diameter that is the same as the diameters of the positioning hole (11) on the copper-clad ceramic substrate (3), the first positioning through hole (10) of the copper-clad ceramic substrate limiting frame (6), and the second positioning through hole (12) of the thermistor limiting frame (7), so as to ensure firm fixation.

3. The fixture structure for thermistor reflow soldering according to claim 2, characterized in that: A reinforcing rib structure is provided inside the copper-clad ceramic substrate limiting frame (6) for improving the overall strength of the copper-clad ceramic substrate limiting frame (6) and keeping the carrier flat and not easily deformed.

4. The fixture structure for thermistor reflow soldering according to claim 2, characterized in that: The copper-clad ceramic substrate (3) consists of an upper surface copper layer, a ceramic layer and a lower surface copper layer which are arranged in sequence from top to bottom, and the area of ​​the middle ceramic layer is larger than the areas of the upper and lower surface copper layers.

5. The fixture structure for thermistor reflow soldering according to claim 2, characterized in that: The thermistor limiting frame (7) is an "h"-shaped structure rotated 90 degrees counterclockwise, and a first positioning through hole (10) is respectively provided at the upper left corner and the lower right corner of the thermistor limiting frame (7), and a thermistor limiting hole (9) is provided at a position close to the end at the upper right corner.

6. The fixture structure for thermistor reflow soldering according to claim 5, characterized in that: The thermistor limiting hole (9) of the thermistor limiting frame (7) is a structure that is wide at the top and narrow at the bottom, making it convenient to clamp the thermistor (4).

7. The fixture structure for thermistor reflow soldering according to claim 1, characterized in that: The side of the heat sink (1) close to the copper-clad ceramic substrate (3) is a welding surface, and the other side opposite thereto is an appearance surface. The welding surface is an arc-shaped surface for relieving stress caused by high-temperature welding.

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