Power chip module pre-tinning process

Abstract

The application provides a power chip module pre-tinning welding process, and relates to the technical field of power chip module welding, and specifically comprises the following steps: cutting a soldering sheet according to the size of a power chip module, and brushing flux on both sides of the soldering sheet; wherein the molten soldering sheet is used as tinning solder; placing the soldering sheet with brushed flux on a corresponding welding area of a substrate of a welding carrier or a module shell of a multi-chip assembly; melting the soldering sheet placed on the welding area by using a heating table and an electric iron to complete tinning of the solder; the application performs pre-tinning treatment on the substrate or the shell welding area of the welding carrier before vacuum reflow welding, completes welding of the power chip module by using the wetting and diffusion of the molten tinning solder, does not need to customize various pressing blocks of the power chip module, reduces the personnel operation process, reduces the chip damage rate, effectively improves the power chip module welding efficiency and the yield, and the process method of the application is simple in operation, friendly in process, and high in assembly efficiency.

Description

Technical Field

[0001] This invention relates to power chip module soldering technology, specifically to a pre-tinning soldering process for power chip modules. Background Technology

[0002] As microwave devices become increasingly powerful and their structural designs more complex, higher demands are placed on heat dissipation. Consequently, the power chip modules of these products require excellent grounding performance and heat dissipation capabilities to ensure long-term stable operation.

[0003] Currently, the main assembly methods for power chip modules are soldering and conductive adhesive bonding. Compared with conductive adhesive bonding, soldering has better heat dissipation, lower contact resistance, higher mechanical strength, and higher reliability, making it more suitable for power chip module assembly. The solder penetration rate directly affects the heat dissipation capacity of the module and is an important process indicator for power chip module soldering.

[0004] In existing technologies, power chip module soldering generally employs manual friction soldering or vacuum eutectic soldering. However, manual friction soldering suffers from problems such as poor assembly consistency, low production efficiency, poor solder penetration, and limited power module size. Vacuum eutectic soldering, on the other hand, requires a custom-made pressure block to apply a certain soldering pressure to the chip module, which is difficult to design and can easily damage the chip during assembly.

[0005] Therefore, how to make the power chip module soldering process simple and reliable, and improve the soldering efficiency and quality of power chip modules, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a pre-tinning soldering process for power chip modules, which solves the problems of limited use of manual friction soldering by using tweezers to pick up the module and the need for customized clamping blocks and easy chip damage during vacuum eutectic soldering.

[0007] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: In this invention, a pre-tinning and soldering process for a power chip module specifically includes the following steps: Cut solder pads according to the dimensions of the power chip module and apply flux to both sides of the solder pads; The molten solder sheet is made of tin-plated solder. Place the solder pads coated with flux onto the corresponding soldering area of ​​the component housing or the substrate of the soldering carrier of the multi-chip module. Use a heating table and soldering iron to melt the solder pieces placed in the soldering area to complete the solder tinning; Clean the component housing after tinning; Wipe a small amount of flux onto the surface of the solder and place the power chip module on top of the solder. The multi-chip assembly with power chip modules is sent into a vacuum reflow oven for reflow soldering.

[0008] Furthermore, the melting temperature of the tin-plated solder is not higher than that of the gold-tin solder, and the solder pads can be indium-lead solder pads, lead-tin solder pads, or tin-lead-indium solder pads.

[0009] Furthermore, the flux can be wiped off the solder pads by brushing or by immersing the solder pads in flux before wiping.

[0010] Furthermore, the preheating temperature of the heating platform is 20-30°C lower than the melting temperature of the solder, and the temperature setting of the soldering iron is 260-300°C.

[0011] Furthermore, the cleaning methods for the tin-plated components are vapor phase cleaning and alcohol brushing.

[0012] Furthermore, the flux on the surface of the tin-plated solder is wiped with a cotton ball.

[0013] Furthermore, a vacuum reflow soldering temperature profile is selected based on the chosen solder. The peak temperature of the profile is about 30°C higher than the melting point of the solder, and the vacuum level in the vacuum zone is set to 100-300 mbar.

[0014] Furthermore, the selected solder is tin-lead-indium solder, the peak temperature of the reflow curve is 185℃, and the vacuum degree is set to 300mbar.

[0015] (III) Beneficial Effects This invention provides a pre-tinning process for power chip modules. Compared with existing technologies, it has the following advantages: This invention pre-tinsifies the substrate or housing welding area of ​​the welding carrier before vacuum reflow soldering, and completes the welding of power chip modules by utilizing the wetting and diffusion effects of the molten solder. This eliminates the need for custom-made power chip module clamps, reduces manual operation, lowers chip damage rate, and effectively improves the welding efficiency and yield of power chip modules. Furthermore, the process method of this invention is simple to operate, process-friendly, and has high assembly efficiency. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the assembly cross-section of the power chip module pre-tinning and soldering process in this solution; Figure 2 This is a radiographic image of the power chip module after the pre-tinning soldering process in this solution.

[0018] Figure label: 1. Welding carrier; 2. Soldering material; 3. Power chip module; 4. Component housing. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] This application provides a pre-tinning soldering process for power chip modules, which solves the problems of limited use of manual friction soldering by using tweezers to pick up the module and the need for customized pressure blocks and easy chip damage during vacuum eutectic soldering, thereby achieving high efficiency in power chip module soldering.

[0021] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0022] like Figure 1 As shown, a pre-tinning soldering process for a power chip module specifically includes the following steps: Step S01: Cut the solder pads according to the size of the power chip module 3, and apply flux to both sides of the solder pads; Among them, the molten solder sheet is tin-plated solder 2; Specifically, the melting temperature of tin-plated solder 2 is not higher than the melting point of gold-tin solder, and the solder pads can be indium lead solder pads, lead-tin solder pads, or tin-lead-indium solder pads, etc. The flux can be wiped off the solder pads by brushing or by immersing the solder pads in flux before wiping. Step S02: Place the solder pads coated with flux onto the corresponding soldering area of ​​the component housing 4 of the multi-chip assembly or the substrate of the soldering carrier 1. Step S03: Use a heating table and a soldering iron to melt the solder pads placed in the soldering area to complete the solder tinning. Specifically, the preheating temperature of the heating table should be 20-30°C lower than the melting temperature of the solder, and the temperature setting of the soldering iron should be 260-300°C. Step S04: Clean the component housing 4 after tinning to remove a large amount of flux used in the tinning process, thus avoiding the problem of flux being difficult to clean after the chip module is assembled. Specifically, the cleaning methods for the tin-plated component housing 4 are vapor phase cleaning and alcohol brushing; Step S05: Wipe a small amount of flux onto the surface of the solder 2 and place the power chip module 3 on top of the solder 2; Specifically, the flux on the surface of the tin-plated solder 2 is wiped with a cotton ball; It should be noted that the solder pads and power chip module 3 are placed by manually picking them up with tweezers; Step S06: The multi-chip assembly equipped with power chip module 3 is sent into a vacuum reflow oven for reflow soldering. Specifically, select a vacuum reflow soldering temperature profile based on the chosen solder. The peak temperature of the profile should be about 30°C higher than the solder melting point, and the vacuum level in the vacuum zone should be set to 100-300 mbar.

[0023] This invention pre-tinsifies the welding area of ​​the substrate or component housing 4 of the welding carrier 1 before vacuum reflow soldering, and completes the welding of the power chip module 3 by utilizing the wetting and diffusion effect of the molten solder. This eliminates the need for custom-made pressure blocks for the power chip module 3, reduces manual operation, lowers chip damage rate, and effectively improves the welding efficiency and yield of the power chip module 3. Furthermore, the process method of this invention is simple to operate, process-friendly, and has high assembly efficiency.

[0024] Example 1: A pre-tinning process for power chip modules, specifically including the following steps: Step 1: Set the hot plate to 150℃ and the soldering iron to 280℃. Apply tin-lead-indium solder to the soldering position of the power chip module 3. After tinning, perform vapor phase cleaning on the component housing 4. Step 2: Apply a small amount of flux to the surface of the tin-lead-indium solder using a cotton ball, and then place the power chip module 3 on top of the solder; Step 3: Place the assembled housing 4 of the power chip module 3 into the vacuum reflow soldering carrier 1 and send it into the reflow oven for reflow soldering. The peak temperature of the reflow curve is 185℃ and the vacuum degree is set to 300mbar. Step 4: After the casing 4 has completely cooled, perform visual inspection and X-ray penetration test, such as... Figure 2 As shown.

[0025] As can be seen from Example 1, the substrate or component housing 4 of the welding carrier 1 is pre-tinned before vacuum reflow soldering. The tinning is done manually with a soldering iron to break the molten tension of the solder pads. Then, the wetting and diffusion of the tinned solder during the vacuum reflow soldering process is used to complete the welding of the power chip module. This process is simple to operate and reliable, and can significantly improve the welding efficiency and quality of the power chip module.

[0026] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0027] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pre-tinning and soldering process for power chip modules, characterized in that, Specifically, the following steps are included: Cut solder pads according to the dimensions of the power chip module and apply flux to both sides of the solder pads; The molten solder sheet is made of tin-plated solder. Place the solder pads coated with flux onto the corresponding soldering area of ​​the component housing or the substrate of the soldering carrier of the multi-chip module. Use a heating table and soldering iron to melt the solder pieces placed in the soldering area to complete the solder tinning; Clean the component housing after tinning; Wipe a small amount of flux onto the surface of the solder and place the power chip module on top of the solder. The multi-chip assembly with power chip modules is sent into a vacuum reflow oven for reflow soldering.

2. The pre-tinning and soldering process for a power chip module as described in claim 1, characterized in that, The melting temperature of tin-plated solder is not higher than that of gold-tin solder, and the solder pads can be indium-lead solder pads, lead-tin solder pads, or tin-lead-indium solder pads.

3. The pre-tinning and soldering process for a power chip module as described in claim 1, characterized in that, The flux can be wiped off the solder pads by brushing or by immersing the solder pads in flux before wiping.

4. The pre-tinning and soldering process for a power chip module as described in claim 1, characterized in that, The preheating temperature of the heating table should be 20-30℃ lower than the melting temperature of the solder, and the temperature setting of the soldering iron should be 260~300℃.

5. The pre-tinning and soldering process for a power chip module as described in claim 1, characterized in that, The cleaning methods for the components after tinning are vapor phase cleaning and alcohol brushing.

6. The pre-tinning and soldering process for a power chip module as described in claim 1, characterized in that, The flux on the surface of tin-plated solder should be wiped with a cotton ball.

7. The pre-tinning and soldering process for a power chip module as described in claim 1, characterized in that, Select the vacuum reflow soldering temperature profile based on the chosen solder. The peak temperature of the profile should be about 30°C higher than the solder melting point. Set the vacuum level in the vacuum zone to 100-300 mbar.

8. The pre-tinning and soldering process for a power chip module as described in claim 7, characterized in that, The selected solder is tin-lead-indium solder, the peak temperature of the reflow curve is 185℃, and the vacuum degree is set to 300mbar.

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