A wafer reflow soldering apparatus

Abstract

This application provides a wafer reflow soldering apparatus, relating to the field of chip packaging technology. The wafer reflow soldering apparatus includes: a frame; a top cover lifting device disposed inside the frame; a chamber device disposed inside the frame, the chamber device including a top cover assembly and a bottom cover assembly, the bottom cover assembly being connected to the frame, and the top cover assembly being connected to the top cover lifting device, allowing it to move vertically via the top cover lifting device and to detach from or engage with the bottom cover assembly to form a sealed chamber. The sealed chamber has multiple wafer processing positions and a conveyor capable of sequentially transporting wafers to the multiple wafer processing positions for progressive heating; and multiple soldering devices, each corresponding to one of the multiple wafer processing positions along the wafer transport path. This wafer reflow soldering apparatus improves the uniformity of soldering temperature while preventing wafer oxidation during soldering.

Description

Technical Field

[0001] This application relates to the field of chip packaging technology, and more particularly to a wafer reflow soldering apparatus. Background Technology

[0002] As the global semiconductor industry rapidly iterates towards higher density, miniaturization, and higher reliability, advanced packaging technologies such as wafer-level packaging (WLP) and system-in-package (SiP) have become core pathways to improve chip performance. Wafer reflow soldering, as a crucial process in the packaging workflow for achieving precise connections between the chip and the substrate, and interconnect bumps, directly determines the yield and reliability of the final product based on the performance of the reflow soldering equipment. Reflow is the process of gradually melting the solder paste applied to the wafer surface into a molten state by raising the temperature.

[0003] Traditional welding equipment has many limitations: early hot air reflow ovens could not achieve precise temperature control of wafer-level micro-areas, which could easily lead to defects such as bump oxidation and solder overflow; while traditional infrared reflow equipment was unevenly heated, could not adapt to the processing needs of wafers with a size of 300mm and larger, and had a slow heating rate, which could not meet the process requirements of high-density interconnects.

[0004] As chip integration continues to increase and bump spacing shrinks from the micrometer level to the nanometer level, more stringent standards are imposed on temperature uniformity, thermal stress control, and contaminant removal efficiency during the welding process. Traditional equipment can no longer meet the technical specifications of advanced processes.

[0005] Furthermore, since the solder paste applied to the wafer surface is prone to oxidation, it is necessary to improve the sealing performance of the wafer reflow soldering equipment to prevent the solder paste from oxidizing. Summary of the Invention

[0006] The purpose of this application is to address the above problems by providing a wafer reflow soldering apparatus that improves the uniformity of soldering temperature while preventing oxidation during wafer soldering.

[0007] This application provides a wafer reflow soldering apparatus, comprising: a frame; a top cover lifting device disposed inside the frame; a chamber device disposed inside the frame, the chamber device including a top cover assembly and a bottom cover assembly, the bottom cover assembly being connected to the frame, and the top cover assembly being connected to the top cover lifting device, so as to move vertically via the top cover lifting device, and be able to detach from or dock with the bottom cover assembly to form a sealed chamber, the sealed chamber having multiple wafer processing positions and a conveying component capable of sequentially conveying wafers to the multiple wafer processing positions for progressive heating of the wafers; and multiple soldering devices, the multiple soldering devices being respectively disposed corresponding to the multiple wafer processing positions on the wafer conveying path, the heating temperature of the multiple soldering devices increasing sequentially.

[0008] According to the technical solutions provided in certain embodiments of this application, the upper cover assembly includes: an upper cover base plate, which is connected to the upper cover lifting device, and the upper cover base plate has a plurality of upper openings corresponding to a plurality of wafer processing positions; a plurality of upper cavity flanges, which are all disposed on the upper surface of the upper cover base plate and correspond to the positions of the plurality of upper openings, and the plurality of upper cavity flanges can move in the vertical direction to open and close the upper openings; and a plurality of rotary cylinders, which are disposed on the edge of the upper cover base plate and can apply pressure to the upper cover assembly and the lower cover assembly when the upper cover assembly and the lower cover assembly are docked to form the sealed chamber.

[0009] According to the technical solutions provided in certain embodiments of this application, the lower cover assembly includes: a lower chamber flange, the lower chamber flange being disposed on the frame, and a plurality of lower openings being provided on the lower chamber flange at positions corresponding to the plurality of upper openings; a lower chamber flange base plate, the lower chamber flange base plate being connected to the lower surface of the lower chamber flange, and a lower chamber small flange being provided at each position corresponding to the plurality of lower openings, so as to be connected to the welding device one by one through the lower chamber small flange.

[0010] According to certain embodiments of the present application, the welding device is disposed on the bottom wall of the frame. The welding device includes: a lower heating base chamber flange, which is connected to the lower chamber small flange; a heating plate frame, which has a heating element inside and can extend into the sealed chamber through the lower opening; a PIN needle lifting plate, which is located below the heating plate frame and can move in the vertical direction; and at least three PIN needle thermocouples, which are disposed on the upper surface of the PIN needle lifting plate and are equidistantly distributed around the center of the wafer. The upper ends of the at least three PIN needle thermocouples pass through the heating plate frame to support the wafer.

[0011] According to the technical solutions provided in certain embodiments of this application, the welding device further includes: a heating base cavity bottom plate, the heating base cavity bottom plate being located below the lower heating base cavity flange; a lower heating base cavity wall, the lower heating base cavity wall being disposed between the heating base cavity bottom plate and the lower heating base cavity flange; a base lifting support plate, the base lifting support plate being located below the heating base cavity bottom plate; a base lifting support column, the two ends of the base lifting support column being respectively connected between the heating base cavity bottom plate and the base lifting support plate; and an electric push cylinder, the electric push cylinder being disposed on the heating base cavity bottom plate, the telescopic end of the electric push cylinder being connected to the PIN pin lifting plate.

[0012] According to the technical solutions provided in certain embodiments of this application, the welding device further includes: a base lifting mechanism connecting plate, the upper surface of which is connected to the lower part of the heating plate frame; and a cylinder, which is disposed on the lower surface of the base lifting support plate, and the output shaft of which is connected to the lower surface of the base lifting mechanism connecting plate.

[0013] According to the technical solutions provided in certain embodiments of this application, the heating plate frame includes: a heating plate, the upper surface of which has a recessed cavity, and the edge of which can abut against the lower surface of the upper cover bottom plate to form a heating cavity; a chuck support plate, the cross-section of which is a T-shaped structure, the upper surface of which is connected to the lower surface of which is the heating plate, and the lower end of which passes through the bottom plate of the heating base cavity and is connected to the output shaft end of the cylinder.

[0014] According to the technical solutions provided in certain embodiments of this application, the upper cover lifting device includes: two transmission components, both of which are connected to the upper cover base plate of the upper cover assembly, and the two transmission components are arranged diagonally relative to the upper cover base plate; a motor, which is disposed on the upper surface of the frame, and the output shaft of the motor is connected to the two transmission components through a reducer.

[0015] According to certain embodiments of this application, the transmission assembly includes: a guide shaft support plate connected to the frame; an optical axis fixing seat disposed on the upper surface of the guide shaft support plate; a lead screw bearing seat disposed on the upper surface of the guide shaft support plate; an upper cover support frame connected to the upper cover base plate; a linear optical axis passing through the upper cover support frame, with both ends of the linear optical axis connected to the optical axis fixing seat and the frame respectively; and a lead screw passing through the upper cover support frame and engaging with the upper cover support frame via a lead screw nut, with both ends of the lead screw connected to the lead screw bearing seat and the frame respectively.

[0016] According to the technical solutions provided in certain embodiments of this application, the upper end of the PIN needle thermocouple is provided with a wafer positioning plate. The upper end of the wafer positioning plate is positioned higher than the plane on the upper surface of the wafer. The wall surface on which the wafer positioning plate abuts against the edge of the wafer is an inclined surface that is tilted in the direction away from the wafer.

[0017] Compared with existing technologies, the beneficial effects of this application are as follows: The frame provides support for the entire device. A top cover lifting device is installed inside the frame to control the lifting and lowering of the top cover assembly of the chamber device. After the top cover assembly and the lower cover assembly of the chamber device are docked, a sealed process chamber is formed, effectively preventing oxidation of the solder paste on the wafer surface during heating. The chamber contains multiple wafer processing stations and transport components, to which wafers are sequentially transported. A soldering device is located below each processing station, and along the transport path, the set heating temperature of each soldering device increases sequentially, achieving precise temperature control of the wafer at each stage. This improves the uniformity of soldering temperature and process reliability, enhances processing stability and wafer yield, and reduces wafer loss.

[0018] It should be understood that the descriptions of technical features, technical solutions, beneficial effects, or similar language in this application do not imply that all features and advantages can be achieved in any single embodiment. Rather, it is understood that the description of a feature or beneficial effect means that a specific technical feature, technical solution, or beneficial effect is included in at least one embodiment. Therefore, the descriptions of technical features, technical solutions, or beneficial effects in this specification do not necessarily refer to the same embodiment. Furthermore, the technical features, technical solutions, and beneficial effects described in this embodiment can be combined in any suitable manner. Those skilled in the art will understand that embodiments can be implemented without one or more specific technical features, technical solutions, or beneficial effects of a particular embodiment. In other embodiments, additional technical features and beneficial effects may be identified in specific embodiments that do not embody all embodiments. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A three-dimensional structural schematic diagram of a wafer reflow soldering apparatus provided in an embodiment of this application;

[0021] Figure 2 This is a three-dimensional structural diagram of a wafer reflow soldering apparatus with the rack portion of the structure hidden, provided in an embodiment of this application.

[0022] Figure 3 A partially enlarged view of the motor position of a wafer reflow soldering apparatus provided in an embodiment of this application;

[0023] Figure 4 A partially enlarged view of the lead screw position of a wafer reflow soldering apparatus provided in an embodiment of this application;

[0024] Figure 5 A partial enlarged view of a lead screw nut limiter for a wafer reflow soldering apparatus provided in an embodiment of this application;

[0025] Figure 6 A three-dimensional structural schematic diagram of a wafer reflow soldering apparatus provided in this application embodiment;

[0026] Figure 7 A cross-sectional side view of a welding apparatus for a wafer reflow soldering device provided in an embodiment of this application;

[0027] Figure 8 A partial enlarged view of the welding apparatus of a wafer reflow soldering device provided in the embodiments of this application;

[0028] Figure 9 A three-dimensional structural schematic diagram of a chamber device for a wafer reflow soldering apparatus provided in this application embodiment;

[0029] Figure 10 A side view of a chamber device of a wafer reflow soldering apparatus provided in an embodiment of this application.

[0030] The text labels in the image represent:

[0031] 1. Rack;

[0032] 2. Top cover lifting device; 204. First servo motor; 205. First drive shaft; 201. Second servo motor; 202. Second drive shaft; 203. Motor; 208. Motor pad; 209. Motor mounting plate; 206. Reducer; 207. Connecting plate; 210. Guide shaft support plate; 211. Optical axis fixing seat; 212. Linear optical axis; 213. Linear bearing; 214. Top cover support frame; 215. Nut guide block; 216. Lead screw; 217. Lead screw nut; 218. Upper limit switch baffle; 219. Nut sleeve; 220. Limit switch; 221. Lead screw bearing seat; 222. Lead screw nut limit clip; 223. Lower limit switch baffle;

[0033] 3. Welding device; 3101. Heating plate frame; 3102. PIN thermocouple; 3103. Wafer positioning plate; 3104. Chuck copper plate; 3105. Heating chuck base plate; 3106. Chuck support plate; 3107. Lifting bellows; 3108. Lower heating base chamber flange; 3109. Lower heating base chamber wall; 3110. Heating base chamber bottom plate; 3111. Base lifting support column; 3112. Base lifting support plate; 3113. Cylinder; 3114. Cylinder lower limit column; 3115. Buffer; 3116. Cylinder mounting parts; 3117. Base lifting... Mechanism connecting plate; 3118, push rod connector; 3119, PIN needle lifting plate; 3120, thermocouple; 3121, first bellows sealing cap; 3122, electric push cylinder; 3123, heating base bellows; 3124, outer ring heating wire; 3125, inner ring heating wire; 3126, cooling water circulation channel; 3127, heat insulation ring; 3128, sealing groove; 3129, second bellows sealing cap; 3130, bellows sealing pressure ring; 3131, bellows sealing ring; 3132, heating chuck connecting flange; 3133, sliding module; 301, cylinder upper limit column;

[0034] 4. Chamber assembly; 401. Upper chamber flange; 402. Upper cover cooling water channel; 403. Upper cover flange; 404. Upper cover base plate; 405. Upper cover water-cooled bend; 406. Rotary cylinder; 407. Lower chamber flange; 414. Lower chamber flange base plate; 408. Diaphragm valve; 409. Needle valve; 410. Membrane gauge; 412. Photoelectric positioning window; 413. Lower chamber small flange; 415. Inlet flow equalization plate; 416. Flow equalization plate sealing groove; 417. Upper cover small flange; 418. Second sealing space; 4120. Pneumatic ultra-high vacuum baffle valve. Detailed Implementation

[0035] To enable those skilled in the art to better understand the technical solutions of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. The descriptions in this section are merely illustrative and explanatory, and should not be construed as limiting the scope of protection of this application. Specifically, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort should fall within the scope of protection of this application.

[0036] It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or apparatus.

[0037] As mentioned in the background section, with the rapid iteration of the global semiconductor industry towards high density, miniaturization, and high reliability, advanced packaging technologies such as wafer-level packaging (WLP) and system-in-package (SiP) have become core paths to improve chip performance. Wafer reflow soldering, as a key process in the packaging workflow to achieve precise connections between the chip and the substrate, and interconnect bumps, directly determines the yield and reliability of the final product based on the performance of the wafer reflow soldering equipment. Reflow is the process of gradually melting the solder paste applied to the wafer surface into a molten state by raising the temperature.

[0038] Traditional welding equipment has many limitations: early hot air reflow ovens could not achieve precise temperature control of wafer-level micro-areas, which could easily lead to defects such as bump oxidation and solder overflow; while traditional infrared reflow equipment was unevenly heated, could not adapt to the processing needs of wafers with a size of 300mm and larger, and had a slow heating rate, which could not meet the process requirements of high-density interconnects.

[0039] As chip integration continues to increase and bump spacing shrinks from the micrometer level to the nanometer level, more stringent standards are imposed on temperature uniformity, thermal stress control, and contaminant removal efficiency during the welding process. Traditional equipment can no longer meet the technical specifications of advanced processes.

[0040] Furthermore, since the solder paste applied to the wafer surface is prone to oxidation, it is necessary to improve the sealing performance of the wafer reflow soldering equipment to prevent the solder paste from oxidizing.

[0041] To address the problems in the prior art, this embodiment provides a wafer reflow soldering apparatus, which is described below in conjunction with the appendix to the specification. Figures 1-10 The wafer reflow soldering apparatus of this application is described in detail.

[0042] like Figure 1 As shown, the wafer reflow soldering apparatus includes a frame 1, a top cover lifting device 2, a chamber device 4, and multiple soldering devices 3.

[0043] The frame 1 serves as the external main structure, providing an installation platform for other internal structures. The top cover lifting device 2 is installed inside the frame 1. The chamber device 4 is also installed inside the frame 1, comprising an upper cover assembly and a lower cover assembly. The lower cover assembly is connected to the frame 1, and the upper cover assembly is connected to the top cover lifting device 2. The upper cover assembly can move vertically via the lifting device 2 and can detach from or dock with the lower cover assembly to form a sealed chamber. Specifically, the docking of the upper and lower cover assemblies forms a sealed chamber. To distinguish it from the subsequent second sealed space 418, the sealed space formed by the docking of the upper and lower cover assemblies is defined as the first sealed space. This prevents oxidation caused by excessive air contact when solder paste is applied to the wafer and delivered into the chamber device 4. Simultaneously, the chamber device 4 can be evacuated, creating a vacuum environment and further reducing solder paste oxidation.

[0044] Furthermore, the sealed chamber contains multiple wafer processing positions and a conveyor system capable of sequentially transporting wafers to these positions for step-by-step heating. This allows the wafers to be transported through multiple processing positions sequentially, enabling processing operations at each position. Multiple welding devices 3 are positioned corresponding to the wafer processing positions along the wafer transport path, with their heating temperatures increasing sequentially. Therefore, after the wafer is transported into the sealed chamber, its temperature is relatively low compared to the ambient temperature. Directly heating the wafer through welding devices 3, which have a large temperature difference with the wafer, could cause it to crack due to excessive localized temperature variations. Thus, the heating process during wafer welding requires a gradual increase in temperature to ensure uniform temperature distribution.

[0045] Therefore, this application, by setting up welding devices 3 with sequentially increasing temperatures at multiple wafer processing positions, enables the wafer heating process to proceed step-by-step, avoiding wafer damage caused by directly heating the wafer using welding devices 3 with a large temperature difference from the wafer. This improves the stability of the wafer reflow soldering process, increases the yield, and thus reduces losses.

[0046] It should be noted that the wafer is heated in stages by a wafer transfer device that transports the wafer in stages. Specifically, the transfer device (not shown in the figure) is located in a sealed chamber inside the chamber device 4. The transfer device includes a rotating disk, the center of which coincides with the center of the chamber device 4. Multiple transfer arms are evenly distributed around the axis of the rotating disk on the rotating disk. The end of each transfer arm away from the rotating disk is equipped with a conveying element capable of clamping and fixing the wafer. Each conveying element corresponds to one of the multiple wafer processing positions.

[0047] Therefore, with each rotation of the rotary table, the positions of multiple conveyor arms move once, and they can move to the next adjacent wafer processing position. Simultaneously, the wafer also moves with the conveyor to the next wafer processing position. Each wafer processing position has a corresponding welding device 3, and the heating temperatures of the multiple welding devices 3 increase sequentially. Therefore, each time the rotary table rotates, the wafer moves to the next wafer processing position with a higher-temperature welding device 3, thereby achieving progressively higher-temperature heating of the wafer. This progressively heated wafer conveying method is a well-known technical solution to those skilled in the art.

[0048] According to the wafer reflow soldering apparatus of this application, the frame 1 provides support for the entire apparatus. A top cover lifting device 2 is installed inside the frame 1 and is used to control the lifting and lowering of the top cover assembly of the chamber device 4. The top cover assembly and the lower cover assembly of the chamber device 4 form a sealed process chamber, i.e., a sealed chamber, which effectively prevents the solder paste on the wafer surface from oxidizing during heating. The chamber contains multiple wafer processing positions and transport components, and the wafers are sequentially transported to each processing position. A soldering device 3 is located below each processing position, and along the transport path, the set heating temperature of each soldering device 3 increases sequentially, achieving precise temperature control of the wafer at each stage. This improves the uniformity of the soldering temperature and the reliability of the process, enhances processing stability and wafer yield, and reduces wafer loss.

[0049] In some embodiments of this application, such as Figure 9 As shown, the upper cover assembly includes an upper cover base plate 404, multiple upper cavity flanges 401, and multiple rotary cylinders 406. The upper cover base plate 404 is connected to the upper cover lifting device 2, and has multiple upper openings corresponding to multiple wafer processing positions. Multiple upper cavity flanges 401 are disposed on the upper surface of the upper cover base plate 404 and correspond to the positions of the multiple upper openings. The multiple upper cavity flanges 401 can move vertically to open and close the upper openings. When the upper cavity flanges 401 close the upper openings, the upper cover base plate 404 becomes a complete cover assembly, capable of sealing with the lower cover assembly to form a sealed chamber. Multiple rotary cylinders 406 are disposed at the edge of the upper cover base plate 404 and can apply pressure to the upper and lower cover assemblies when they are joined to form a sealed chamber. By clamping the upper and lower cover assemblies with the rotary cylinders 406, the sealing effect of the sealed chamber is ensured, preventing air from entering or leakage.

[0050] Specifically, the upper cover base plate 404 is driven to lift as a whole by the upper cover lifting device 2. Multiple openings are provided on it for easy observation or process operation. Each opening is equipped with an independently liftable upper cavity flange 401 for opening and closing the corresponding opening, increasing operational flexibility. Multiple rotary cylinders 406 are distributed along the edge of the upper cover base plate 404. When the upper cover assembly and the lower cover assembly are docked, the rotary cylinders 406 actuate, applying downward pressure to ensure a tight seal between the upper and lower assemblies, thereby achieving a high degree of airtightness in the sealed chamber and effectively isolating air.

[0051] In some embodiments of this application, such as Figure 10 As shown, the lower cover assembly includes a lower chamber flange 407 and a lower chamber flange base plate 414. The lower chamber flange 407 is mounted to the frame 1, and multiple lower openings are provided on the lower chamber flange 407 at positions corresponding to multiple upper openings. The lower chamber flange base plate 414 is connected to the lower surface of the lower chamber flange 407, and a lower chamber small flange 413 is provided at each position corresponding to the multiple lower openings, so as to be connected to the welding device 3 one by one through the lower chamber small flange 413. Therefore, after the welding device 3 is connected to the lower chamber small flange 413, the multiple lower openings of the lower cover assembly are sealed, so that the lower cover assembly can form a sealed chamber with the upper cover assembly.

[0052] Specifically, such as Figure 9 and Figure 10 As shown, the lower chamber flange 407 is fixed to the frame 1, and its lower opening corresponds one-to-one with the upper opening of the upper cover base plate 404. The lower chamber flange base plate 414 reinforces the structure of the lower cover assembly, and the lower chamber small flange 413 on it provides a standard and reliable installation interface for each welding device 3, ensuring the sealing and alignment between the welding device 3 and the sealing chamber, and facilitating independent installation and maintenance of each station.

[0053] In some embodiments of this application, the welding device 3 is disposed on the bottom wall of the frame 1. The welding device 3 includes a lower heating base chamber flange 3108, a heating plate frame 3101, a PIN needle lifting plate 3119, and at least three PIN needle thermocouples 3102. The lower heating base chamber flange 3108 is connected to the lower chamber small flange 413. Therefore, a stable and sealed connection can be achieved between the welding device 3 and the lower cover assembly. The heating plate frame 3101 contains a heating element and can extend into the sealed chamber through the lower opening. The heating plate frame 3101 can heat the wafer; the heating process of the wafer by the heating plate frame 3101 needs to be described here.

[0054] As those skilled in the art know, wafers are inherently fragile and have intricate circuitry and solder bumps on their surface. Therefore, direct contact between the wafer and the heating pad frame 3101 can easily scratch the wafer surface or damage the bumps, leading to decreased yield. Due to rapid heat conduction at the contact point, localized overheating can cause uneven solder melting, and even result in die abnormalities and solder joint voids. Furthermore, minute impurities on the surface of the heating pad frame 3101 can contaminate the wafer, failing to meet the cleanliness requirements of semiconductor packaging. Therefore, the entire wafer reflow soldering process involves suspended heating, avoiding direct contact with the heating pad frame 3101 and other heating structures.

[0055] Therefore, the heating of the wafer by the heating plate frame 3101 is generally achieved through radiative heat transfer. Heating components, such as furnace heating plates or heating lamps, emit infrared radiation. The heating lamps can be infrared heating tubes or graphite radiation heaters. No medium is needed; the radiation acts directly on the wafer surface. The wafer absorbs the radiant energy and converts it into heat energy, achieving overall temperature rise to meet the high-precision wafer soldering requirements. Some heat can also be transferred through inert gas convection. To prevent oxidation, wafer reflow soldering is often performed in an inert atmosphere such as nitrogen or argon. The heating plate heats the surrounding inert gas, and the gas naturally convection carries some heat to the wafer, assisting in temperature rise. Furthermore, convection heat transfer can compensate for the small temperature difference at the wafer edges during radiative heat transfer, making the temperature rise more uniform. A small portion of heat is transferred through conduction. Although there is no direct contact between the wafer and the heating components, the wafer indirectly conducts a small amount of heat through support fixtures such as ceramic stages or graphite boats. However, the contact between the fixture and the wafer is shallow or suspended, and the conduction rate is extremely low, only playing a supporting role in temperature control.

[0056] In actual processes, the non-contact heating effect is optimized in two ways. One is by controlling the distance between the heating element and the wafer; too much distance results in significant radiative heat loss, while too little distance leads to localized overheating. The second method involves incorporating insulation design within the wafer reflow soldering apparatus to reduce radiative heat loss, coupled with multi-point temperature measurement and closed-loop regulation to measure the wafer surface temperature and the furnace atmosphere temperature. This ensures the heating curve closely matches the solder melting point requirements. In this application, a heating plate frame 3101 is used for wafer heating; the principle will be explained later.

[0057] like Figure 6As shown, the PIN lifting plate 3119 is located below the heating plate frame 3101 and can move vertically. At least three PIN thermocouples 3102 are disposed on the upper surface of the PIN lifting plate 3119 and are equidistantly distributed around the center of the wafer. The upper ends of the at least three PIN thermocouples 3102 pass through the heating plate frame 3101 to support the wafer. This allows the wafer to be supported at three equidistant points by the at least three PIN thermocouples 3102, maintaining wafer stability. Furthermore, since the heating plate frame 3101 is the heating device and the PIN thermocouples 3102 are the wafer-supporting devices, as mentioned earlier, the greater the distance between the wafer and the heating plate frame 3101, the slower the temperature transfer. Therefore, by controlling the vertical movement of the PIN thermocouples 3102, the distance between the wafer and the heating plate frame 3101 is adjusted, thereby adjusting the temperature transfer rate. This allows for more uniform heating of the wafer and prevents excessively rapid local heating that could lead to wafer breakage.

[0058] Furthermore, by controlling the movement of the PIN thermocouple 3102 to adjust the distance between the wafer and the heating plate frame 3101, compared to the method where the PIN thermocouple 3102 is placed on the upper surface of the heating plate frame 3101 and supports the wafer, the PIN thermocouple 3102 has a smaller overall mass and less inertia during movement, making it easier to adjust the movement of the PIN thermocouple 3102, thus resulting in greater stability when adjusting the vertical position of the wafer.

[0059] In some embodiments of this application, the welding apparatus 3 further includes a heating base cavity bottom plate 3110, a lower heating base cavity wall 3109, a base lifting support plate 3112, a base lifting support column 3111, and an electric push cylinder 3122. The heating base cavity bottom plate 3110 is located below the lower heating base cavity flange 3108. The lower heating base cavity wall 3109 is disposed between the heating base cavity bottom plate 3110 and the lower heating base cavity flange 3108. The base lifting support plate 3112 is located below the heating base cavity bottom plate 3110. Both ends of the base lifting support column 3111 are respectively connected between the heating base cavity bottom plate 3110 and the base lifting support plate 3112. The electric push cylinder 3122 is disposed on the heating base cavity bottom plate 3110, and the telescopic end of the electric push cylinder 3122 is connected to the PIN needle lifting plate 3119.

[0060] Specifically, such as Figure 6As shown, the heating base cavity bottom plate 3110, the lower heating base cavity wall 3109, and the lower heating base cavity flange 3108 together form a stable base. The base lifting support plate 3112 is connected to the heating base cavity bottom plate 3110 through the base lifting support column 3111, forming a reliable support frame. The electric push cylinder 3122 is fixed on the heating base cavity bottom plate 3110, and its telescopic end directly drives the PIN needle lifting plate 3119, realizing precise and stable control of the lifting movement of the PIN needle thermocouple 3102, ensuring the reliability of wafer pick-up and placement operations.

[0061] In some embodiments of this application, such as Figure 6 As shown, the welding device 3 also includes a base lifting mechanism connecting plate 3117 and a cylinder 3113. The upper surface of the base lifting mechanism connecting plate 3117 is connected to the lower part of the heating plate frame 3101. The cylinder 3113 is disposed on the lower surface of the base lifting support plate 3112, and the output shaft of the cylinder 3113 is connected to the lower surface of the base lifting mechanism connecting plate 3117.

[0062] Specifically, the base lifting mechanism connecting plate 3117 connects the heating plate frame 3101 to the drive mechanism below. The cylinder 3113 is installed below the base lifting support plate 3112, and its output shaft drives the base lifting mechanism connecting plate 3117, thereby causing the entire heating plate frame 3101 to perform a large-stroke lifting movement. This allows the heating plate frame 3101 to extend into or retract from the process chamber as needed, facilitating process preparation and equipment maintenance.

[0063] In some embodiments of this application, such as Figure 7 As shown, the heating plate frame 3101 includes a heating plate and a chuck support plate 3106. The upper surface of the heating plate has a recessed cavity, and the edge of the heating plate can abut against the lower surface of the upper cover base plate 404 to form a heating cavity. The chuck support plate 3106 has a T-shaped cross-section, the upper surface of the chuck support plate 3106 is connected to the lower surface of the heating plate, and the lower end of the chuck support plate 3106 passes through the heating base cavity base plate 3110 and is connected to the output shaft end of the cylinder 3113.

[0064] Specifically, such as Figure 7As shown, the top of the heating plate frame 3101 is the heating plate itself, and its recessed cavity forms a more concentrated thermal field with the back of the wafer. After the upper cover assembly and the lower cover assembly are docked, the cylinder 3113 raises the overall height of the heating plate frame 3101 so that the edge of the heating plate abuts against the lower surface of the upper cover assembly. This creates an independent heating chamber between the recessed cavity of the heating plate and the lower surface of the upper cover assembly, and the wafer is placed inside the heating chamber. This further optimizes the uniformity of the thermal field and reduces heat loss. At this time, a vacuum can be drawn again to ensure the vacuum environment inside the sealed chamber and the heating chamber. The T-shaped chuck tray 3106 has a stable structure, with the heating plate connected to it on top and passing through the bottom plate of the base cavity to connect with the output shaft of the cylinder 3113, transmitting lifting power. It has a compact structure and good rigidity.

[0065] In some embodiments of this application, such as Figure 2 and Figure 3 As shown, the upper cover lifting device 2 includes two transmission components and a motor 203. Both transmission components are connected to the upper cover base plate 404 of the upper cover assembly, and the two transmission components are arranged diagonally relative to the upper cover base plate 404. The motor 203 is mounted on the upper surface of the frame 1, and the output shaft of the motor 203 is connected to the two transmission components through a reducer 206.

[0066] Specifically, such as Figure 2 and Figure 3 As shown, the upper cover lifting device 2 uses two symmetrically arranged transmission components on opposite diagonals to drive the upper cover base plate 404, ensuring the smoothness and synchronization of the upper cover assembly's lifting process and preventing jamming or skewness. A single motor 203 distributes power to the two transmission components through a reducer 206, achieving synchronized drive, simplified structure, and convenient control. The reducer 206 can reduce the speed and increase the torque.

[0067] In some embodiments of this application, such as Figure 4 As shown, the transmission assembly includes a guide shaft support plate 210, an optical axis fixing seat 211, a lead screw bearing seat 221, an upper cover support frame 214, a linear optical axis 212, and a lead screw 216. The guide shaft support plate 210 is connected to the frame 1. The optical axis fixing seat 211 is disposed on the upper surface of the guide shaft support plate 210. The lead screw bearing seat 221 is disposed on the upper surface of the guide shaft support plate 210. The upper cover support frame 214 is connected to the upper cover bottom plate 404. The linear optical axis 212 passes through the upper cover support frame 214, and both ends of the linear optical axis 212 are respectively connected to the optical axis fixing seat 211 and the frame 1. The lead screw 216 passes through the upper cover support frame 214 and cooperates with the upper cover support frame 214 through a lead screw nut 217. Both ends of the lead screw 216 are respectively connected to the lead screw bearing seat 221 and the frame 1.

[0068] Specifically, such as Figure 4As shown, in each transmission assembly, the linear optical shaft 212 and the lead screw 216 are arranged in parallel. The upper cover support frame 214 is respectively fitted onto the linear optical shaft 212 and the lead screw 216 via a linear bearing 213 and a lead screw nut 217. The linear optical shaft 212 forms a guide rail, and the motor 203 drives the lead screw 216 to rotate. The lead screw nut 217 cooperates with the lead screw 216 to make the upper cover support frame 214 move up and down along the linear optical shaft 212. The lead screw bearing seat 221 and the optical shaft fixing seat 211 provide stable support. The lead screw nut 217 and the lead screw 216 form a lead screw nut transmission method with the advantages of good self-locking, high positioning accuracy, and large load-bearing capacity, ensuring the positioning accuracy of the upper cover assembly.

[0069] In some embodiments of this application, such as Figure 6 and Figure 7 As shown, the upper end of the PIN needle thermocouple 3102 is provided with a wafer positioning piece 3103. The upper end of the wafer positioning piece 3103 is higher than the plane on the upper surface of the wafer. The wall surface of the wafer positioning piece 3103 that abuts against the edge of the wafer is an inclined surface that is inclined in the direction away from the wafer.

[0070] Specifically, the height of the wafer positioning plate 3103 at the top of the PIN thermocouple 3102 is set to ensure contact with the edge of the wafer. The wall surface of the wafer positioning plate 3103 that contacts the wafer is designed as an outwardly inclined surface. When the wafer is placed down, its edge will slide down along the inclined surface under the action of gravity until it is stopped by the bottom of the inclined surface, thereby realizing automatic alignment of the wafer on the horizontal plane, ensuring the alignment of the wafer with the center of the heating plate, which is convenient for uniform heating and subsequent process operations.

[0071] Furthermore, this application is not limited thereto; in some embodiments of this application, such as Figures 2-5 As shown, the transmission assembly also includes a first servo motor 204, a first drive shaft 205, a second servo motor 201, a second drive shaft 202, a motor pad 208, a motor mounting plate 209, a connecting plate 207, a linear bearing 213, an upper cover support frame 214, a nut guide block 215, an upper limit switch baffle 218, a nut sleeve 219, a limit switch 220, a lead screw nut limit clip 222, and a lower limit switch baffle 223.

[0072] like Figure 2 As shown, motor 203 provides lifting power, and the output shaft of motor 203 is connected to reducer 206. Figure 3As shown, the motor mounting plate 209 is fixed to the top of the frame 1, and the motor 203 is located on the motor mounting plate 209 and is mounted on the motor mounting plate 209 by motor pads 208. The reducer 206 is connected to two first drive shafts 205 on both sides via connecting discs 207. Each end of the two first drive shafts 205 is connected to a first servo motor 204. One of the first servo motors 204 is connected to a second drive shaft 202, and the other end of the second drive shaft 202 is connected to a second servo motor 201. The other first servo motor 204, which is not connected to the second servo motor 201, is arranged diagonally opposite to the second servo motor 201. Figure 2 As shown, the two second servo motors 201 arranged diagonally are both connected to lead screws 216 symmetrically arranged in the vertical direction to transmit power to the lead screws 216. One end of the lead screw 216 is connected to the second servo motor 201, and the other end of the lead screw 216 is connected to the lead screw bearing housing 221.

[0073] like Figure 4 As shown, the lead screw 216 is the power device for lifting the upper cover. An upper cover support frame 214 is also provided on the edge of the upper cover, welded to the edge. A lead screw nut 217 is embedded in the upper cover support frame 214. A nut sleeve 219 and a nut guide block 215 cooperate with the lead screw 216 to lift the upper cover. The lead screw nut 217 is mounted on the nut sleeve 219 and connected by bolts, ensuring that the lead screw nut 217 drives the upper cover support frame 214 to lift and lower. The lead screw nut limiter 222 is a limiting device for fixing the nut sleeve 219. The protruding part of the nut guide block 215 is inserted into the upper cover support frame 214, restricting the rotation of the lead screw nut 217. The upper cover support frame 214 is also equipped with an upper limit switch baffle 218 to work with the limit switch on the frame 1 to complete the upper limit position, and a lower limit switch baffle 223 is set under the screw nut limit card 222 to work with the limit switch 220 on the guide shaft support plate 210 to complete the lower limit position, so as to prevent the upper cover from rising or falling excessively.

[0074] The upper limit switch and the limit switch 220 have the same structural principle, which can be understood by those skilled in the art without any doubt, and will not be elaborated here.

[0075] In some embodiments of this application, such as Figures 9-10 As shown, the upper cover assembly may further include an upper cover cooling water channel 402, an upper cover flange 403, and an upper cover water-cooled elbow 405. The lower cover assembly may further include a diaphragm valve 408, a needle valve 409, a diaphragm gauge 410, a photoelectric positioning window 412, a pneumatic ultra-high vacuum baffle valve 4120, a lower chamber small flange 413, an air inlet flow equalization plate 415, a flow equalization plate sealing groove 416, an upper cover small flange 417, and a second sealing space 418.

[0076] Specifically, such as Figure 9As shown, the upper cavity flange 401, the upper cover flange 403, and the upper cover base plate 404 constitute the upper cavity space. Figure 10 As shown, the lower chamber flange 407, lower chamber flange base plate 414, lower chamber small flange 413, and welding device 3 constitute the lower chamber space. A sealing ring is installed between the upper chamber flange 401 and the lower chamber flange 407 for sealing, and a sealing ring is installed between the upper cover flange 403 and the upper cover base plate 404 for sealing. The upper cover cooling water channel 402 is used to reduce the temperature of the upper cover flange 403, preventing deformation and gaps caused by repeated heating, which could lead to product oxidation. The upper cover water-cooled bend 405 is used to reduce the temperature of the upper cover base plate 404 during welding, preventing deformation due to repeated heating. The rotary cylinder 406 is used to clamp the upper cover base plate 404 of the upper cover assembly and the lower chamber flange 407 of the lower cover assembly, preventing oxygen from entering. A sealing ring is pressed between the lower heating base chamber flange 3108 and the lower chamber small flange 413 in the welding device 3 for sealing. The diaphragm valve 408 prevents contamination or corrosion and also acts as a main switch to control fluid flow. Needle valve 409 is used to precisely regulate the flow rate of nitrogen and formic acid and control the gas flow. Thin-film gauge 410 is used to measure the gas pressure inside the cavity, reflecting the vacuum level and pressure holding capacity. Photoelectric positioning window 412 is used for positioning the moving wafer during pre- and post-welding processes. Pneumatic ultra-high vacuum baffle valve 4120 is used to prevent air from the vacuum line from flowing back into the cavity.

[0077] In some embodiments of this application, such as Figures 6-8 As shown, the welding device 3 also includes a wafer positioning plate 3103, a chuck copper plate 3104, a heated chuck base plate 3105, a chuck support plate 3106, a lifting bellows 3107, a cylinder lower limit post 3114, a buffer 3115, a cylinder mounting component 3116, a push rod connector 3118, a thermocouple 3120, a first bellows sealing cap 3121, an electric push cylinder 3122, a heated base bellows 3123, an outer ring heating wire 3124, an inner ring heating wire 3125, a cooling water circulation channel 3126, a heat insulation ring 3127, a sealing groove 3128, a second bellows sealing cap 3129, a bellows sealing pressure ring 3130, a bellows sealing ring 3131, a heated chuck connecting flange 3132, and a sliding module 3133.

[0078] Specifically, such as Figure 6 As shown, the welding device 3 is the process execution position for wafer preheating and welding. As mentioned above, multiple PIN thermocouples 3102 are evenly distributed on the heating plate frame 3101 of the welding device 3. Wafer positioning pieces 3103 are set on the PIN thermocouples 3102. The wafer is supported by three PIN thermocouples 3102. The top of the PIN thermocouples 3102 has a temperature detection element, which can measure the temperature of the wafer in real time.

[0079] When the solder reflow is performed, such as Figure 10As shown, the upper edge of the heating plate of the heating plate frame 3101 is in close contact with the flow equalization plate sealing groove 416 provided below the air inlet flow equalization plate 415 on the lower side of the upper cavity flange 401. Flow equalization plate sealing grooves 416 are provided both above and below the air inlet flow equalization plate 415 flange. A sealing ring is pressed in to form... Figure 10 The dotted line in the figure shows a sealed second sealing space 418, which realizes the vacuum process and atmosphere reduction process in the welding process.

[0080] Among them, such as Figure 7 As shown, the heating plate frame 3101 has a multi-layered structure. A cavity is formed between the heating plate and the chuck support plate 3106. From top to bottom, the cavity contains a chuck copper plate 3104, a heating chuck base plate 3105, an inner ring heating wire 3125, and an outer ring heating wire 3124. The inner ring heating wire 3125 has a lower density than the outer ring heating wire 3124. This sparse inner ring and dense outer ring arrangement provides a uniform heating field for the wafer within the heating chuck base plate 3105. The chuck copper plate 3104, located above the heating chuck base plate 3105, further ensures uniform heat conduction. The chuck support plate 3106 and the heating plate frame 3101 form a chamber that encloses the chuck copper plate 3104 and the heating chuck base plate 3105, forming the heating cavity. The chuck copper plate 3104 can also be made of other thermally conductive materials, depending on the actual usage requirements, and is not limited to copper.

[0081] Furthermore, the chuck support plate 3106 is provided with a conventional tubular structure, and a heating chuck connecting flange 3132 is provided at the bottom of the device. A heat insulation ring 3127 is provided below the heating chuck connecting flange 3132. The heat insulation ring 3127 is installed on the inner flange of the heating base bellows 3123 to block the transmission of heat and reduce heat loss. The aforementioned inner ring heating wire 3125, outer ring heating wire 3124 and thermocouple 3120 are all inserted from bottom to top through the tubular structure and are located below the chuck copper plate 3104. The heating cavity is provided with a lower heating base chamber flange 3108, a lower heating base chamber wall 3109, and a heating base chamber bottom plate 3110 at the bottom. The lower heating base chamber wall 3109 and the heating base chamber bottom plate 3110 form a cavity. The shape of the lower heating base chamber flange 3108 is connected to the lower chamber small flange 413 to form a second sealing space 418, which forms an overall sealing space to achieve a high vacuum and low oxygen environment during the welding process. The heating base chamber bottom plate 3110 is also provided with a cooling water circulation channel 3126 to cool the wafer and reduce heat conduction during the heating process, and to prevent the heating base chamber bottom plate 3110 from deforming at high temperature.

[0082] like Figure 6As shown, a cylinder 3113 is installed below the base lifting support plate 3112, and a lower limit post 3114 is installed above it. The cylinder rod of the cylinder 3113 passes through the base lifting support plate 3112 and is connected to the cylinder mounting component 3116. The cylinder mounting component 3116 has symmetrical reinforcing ribs inside to increase the edge bearing capacity of the cylinder mounting component 3116. The lower part has a through groove adapted to the cylinder rod of the cylinder 3113, so that the cylinder rod of the cylinder 3113 can lift the entire device. The upper end of the cylinder mounting component 3116 is connected to the base lifting mechanism connecting plate 3117. Multiple buffers 3115 are installed on the upper and lower surfaces of the base lifting mechanism connecting plate 3117. The buffers 3115, together with the upper limit post 301 and the lower limit post 3114, limit the stroke of the cylinder 3113. The cylinder upper limit post 301 is located on the upper surface of the base lifting mechanism connecting plate 3117. A contact structure is provided on the lower surface of the heating base cavity bottom plate 3110 corresponding to the position of the cylinder upper limit post 301. A through hole is opened on the PIN needle lifting plate 3119 corresponding to the position of the cylinder upper limit post 301, allowing the cylinder upper limit post 301 to pass through the PIN needle lifting plate 3119 during upward movement. When the cylinder upper limit post 301 rises and contacts the contact structure, the upward stroke stops, thus limiting the lifting height. Protruding rectangular blocks are provided on the lower sides of both ends of the base lifting mechanism connecting plate 3117. These rectangular blocks connect to the sliding module 3133 on the base lifting support column 3111, enabling the lifting of the base. The lower end of the bellows pipe 3123 of the heating base is connected to the connecting plate 3117 of the base lifting mechanism, and the upper end is connected to the bottom plate 3110 of the heating base cavity through a flange. The flange is grooved on the side near the bottom plate 3110 of the heating base cavity, and a sealing ring is pressed in for sealing.

[0083] In some embodiments of this application, such as Figure 6 and Figure 7As shown, the wafer reflow soldering apparatus of this application also includes a bellows sealing cap 3129 and a push rod connector 3118. An electric push cylinder 3122 is mounted on the edge of the heating base cavity bottom plate 3110 via a mounting plate. The cylinder rod of the electric push cylinder 3122 extends and retracts vertically. A push rod connector 3118 is provided at the output end of the cylinder rod. This push rod connector 3118 is an L-shaped plate, with one surface connected to the cylinder rod output end and the other surface perpendicular to the horizontal plane. Furthermore, another push rod connector 3118, also an L-shaped plate, is bolted to the lower surface of the PIN needle lifting plate 3119. One surface of this L-shaped plate is connected to the lower surface of the PIN needle lifting plate 3119, and the other surface is perpendicular to the horizontal plane. The vertical and horizontal surfaces of the L-shaped plates of the two push rod connectors 3118 are connected by bolts, thereby forming an integrated and stable S-shaped structural component. When the cylinder rod of the electric pusher cylinder 3122 extends or retracts, it can stably push the PIN needle lifting plate 3119. The PIN needle lifting plate 3119 has multiple through holes, allowing the buffer 3115 to pass through and preventing interference during movement. Multiple PIN needle thermocouples 3102 are installed on the PIN needle lifting plate 3119. The PIN needle thermocouples 3102 extend upwards from the bottom plate 3110 of the heating base cavity until they protrude through the heating plate frame 3101, where they monitor temperature. They then seal with the contact surface between the bottom plate 3110 of the heating base cavity and the bottom plate 3105 of the heating chuck. Figure 7 and Figure 8 As shown, the sealing structure may include a lifting bellows 3107, a bellows sealing ring 3131, a bellows sealing pressure ring 3130, and a bellows sealing cap 3129. The upper flange of the lifting bellows 3107 is grooved, and a sealing ring is inserted to achieve the sealing function. The lower end is filled with a double-layer sealing ring through the gap of the bellows sealing pressure ring 3130. The outer side of the bellows sealing pressure ring 3130 is provided with threads, which cooperate with the internal threads of the threaded pipe sealing cap 3129 to seal the PIN thermocouple 3102.

[0084] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. The above descriptions are only preferred embodiments of this application. It should be noted that due to the limitations of textual expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of this application, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the concept and technical solution of the application to other occasions without modification, should all be considered within the scope of protection of this application.

Claims

1. A wafer reflow soldering apparatus, characterized in that, include: Rack (1); The upper cover lifting device (2) is installed inside the frame (1); A chamber device (4) is disposed in the frame (1). The chamber device (4) includes an upper cover assembly and a lower cover assembly. The lower cover assembly is connected to the frame (1), and the upper cover assembly is connected to the upper cover lifting device (2) so that it can move in the vertical direction through the upper cover lifting device (2) and can be disengaged from or docked with the lower cover assembly to form a sealed chamber. The sealed space formed after the upper cover assembly and the lower cover assembly dock is the first sealed space. The interior of the sealed chamber has multiple wafer processing positions and a conveying component that can sequentially transport the wafer to the multiple wafer processing positions to heat the wafer step by step. Multiple welding devices (3) are provided, each corresponding to a multiple wafer processing position on the wafer transport path, and the heating temperature of the multiple welding devices (3) increases sequentially. The upper cover assembly includes: The upper cover base plate (404) is connected to the upper cover lifting device (2), and the upper cover base plate (404) has a plurality of upper openings corresponding to a plurality of wafer processing positions; Multiple upper cavity flanges (401) are provided on the upper surface of the upper cover bottom plate (404) and correspond to the positions of multiple upper openings respectively. The multiple upper cavity flanges (401) can move in the vertical direction to open and close the upper openings. Multiple rotary cylinders (406) are disposed at the edge of the upper cover base plate (404) and are capable of applying pressure to the upper cover assembly and the lower cover assembly when the upper cover assembly and the lower cover assembly are mated to form the sealed chamber; The lower cover assembly includes: A lower chamber flange (407) is provided on the frame (1), and a plurality of lower openings are provided on the lower chamber flange (407) at positions corresponding to the plurality of upper openings; The lower chamber flange base plate (414) is connected to the lower surface of the lower chamber flange (407), and a lower chamber small flange (413) is provided at the position of each of the multiple lower openings, so as to be connected to the welding device (3) one by one through the lower chamber small flange (413); The welding device (3) is disposed on the bottom wall of the frame (1), and the welding device (3) includes: The lower heating base chamber flange (3108) is connected to the lower chamber small flange (413); A heating plate frame (3101) is provided, which contains a heating element. The heating plate frame (3101) can extend into the sealed cavity through the lower opening. The upper edge of the heating plate of the heating plate frame (3101) is in close contact with the flow equalization plate sealing groove (416) provided below the air inlet flow equalization plate (415) on the lower side of the upper cavity flange (401). The air inlet flow equalization plate (415) flange is provided with flow equalization plate sealing groove (416) on both the upper and lower sides. A sealing ring is pressed in to form a sealed second sealing space (418). The PIN lifting plate (3119) is located below the heating plate frame (3101) and can move in the vertical direction; At least three PIN thermocouples (3102) are disposed on the upper surface of the PIN lifting plate (3119) and are distributed at equal intervals around the center of the wafer. The upper ends of the at least three PIN thermocouples (3102) pass through the heating plate frame (3101) to support the wafer. The upper end of the PIN needle thermocouple (3102) is provided with a wafer positioning piece (3103). The upper end of the wafer positioning piece (3103) is higher than the plane on the upper surface of the wafer. The wall surface of the wafer positioning piece (3103) that abuts against the edge of the wafer is an inclined surface that is inclined in the direction away from the wafer. The welding device (3) further includes: A heating base cavity bottom plate (3110) is located below the lower heating base cavity flange (3108); The lower heating base chamber wall (3109) is disposed between the heating base chamber bottom plate (3110) and the lower heating base chamber flange (3108); The base lifting support plate (3112) is located below the bottom plate (3110) of the heating base cavity; The base lifting support column (3111) has its two ends connected between the bottom plate (3110) of the heating base cavity and the base lifting support plate (3112), respectively. An electric push cylinder (3122) is mounted on the bottom plate (3110) of the heating base cavity, and the telescopic end of the electric push cylinder (3122) is connected to the PIN needle lifting plate (3119).

2. The wafer reflow soldering apparatus according to claim 1, characterized in that, The welding device (3) further includes: The base lifting mechanism connecting plate (3117) has its upper surface connected to the lower part of the heating plate frame (3101). A cylinder (3113) is disposed on the lower surface of the base lifting support plate (3112), and the output shaft of the cylinder (3113) is connected to the lower surface of the base lifting mechanism connecting plate (3117).

3. The wafer reflow soldering apparatus according to claim 2, characterized in that, The heating plate frame (3101) includes: A heating plate, the upper surface of which has a recessed cavity, and the edge of which can abut against the lower surface of the upper cover bottom plate (404) to form a heating cavity; The chuck tray (3106) has a T-shaped cross-section. The upper surface of the chuck tray (3106) is connected to the lower surface of the heating plate. The lower end of the chuck tray (3106) passes through the bottom plate (3110) of the heating base cavity and is connected to the output shaft end of the cylinder (3113).

4. The wafer reflow soldering apparatus according to claim 3, characterized in that, The upper cover lifting device (2) includes: Two transmission components are provided, both of which are connected to the bottom plate (404) of the top cover assembly, and the two transmission components are arranged diagonally relative to the bottom plate (404). The motor (203) is mounted on the upper surface of the frame (1), and the output shaft of the motor (203) is connected to the two transmission components via a reducer (206).

5. The wafer reflow soldering apparatus according to claim 4, characterized in that, The transmission assembly includes: Guide shaft support plate (210), the guide shaft support plate (210) is connected to the frame (1); Optical axis fixing seat (211), the optical axis fixing seat (211) is disposed on the upper surface of the guide shaft support plate (210); A lead screw bearing housing (221) is disposed on the upper surface of the guide shaft support plate (210); The upper cover support frame (214) is connected to the upper cover bottom plate (404); A linear optical axis (212) passes through the upper cover support frame (214), and the two ends of the linear optical axis (212) are respectively connected to the optical axis fixing seat (211) and the frame (1). The lead screw (216) passes through the upper cover support frame (214) and cooperates with the upper cover support frame (214) through the lead screw nut (217). The two ends of the lead screw (216) are respectively connected to the lead screw bearing seat (221) and the frame (1).

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