Wafer backflow vacuum furnace

Abstract

The utility model relates to the technical field of semiconductor chip processing, in particular to a wafer backflow vacuum furnace, which comprises a second preheating area, a welding area, a cooling plate, an air bag, a plurality of gate valves and a first cooling area. The second preheating area, the welding area and the first cooling area are arranged according to the working process, the gate valve is arranged at the inlet end of the second preheating area, the gate valve is arranged at the outlet end of the second preheating area, the gate valve is arranged at the inlet end of the welding area, the gate valve is arranged at the outlet end of the welding area, and the gate valve is arranged at the inlet end of the first cooling area. The gate valve is arranged at the inlet end of the first cooling area, the gate valve is arranged at the outlet end of the first cooling area, the cooling plate is arranged in the first cooling area, the air bag is arranged on the cooling plate, and a plurality of first fine holes are symmetrically and uniformly formed in the air bag. In the wafer backflow process, the impact is small, and the heat dissipation uniformity is good.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of semiconductor chip processing especially relates to a wafer reflow vacuum furnace. BACKGROUND

[0002] The reflow soldering process is an important process flow in the electronic process field and is mainly used for soldering some small components. In the advanced packaging process of semiconductors, the reflow soldering process is also used for processing the pins of formed chips. The traditional reflow soldering process is carried out in the fluxing agent mode, which requires pre-coating of the fluxing agent and cleaning of the fluxing agent after the reflow process, and the process is complex and the production cost is high. The advanced packaging process of semiconductors adopts a more advanced formic acid reflow process, which does not require spin coating and cleaning of the fluxing agent, and has the advantages of simple process, low cost and high capacity. However, there are few similar devices in the industry at present, and only a few foreign manufacturers have similar devices, which have a large impact during the wafer reflow cooling process and poor heat dissipation uniformity. SUMMARY

[0003] The utility model provides a wafer reflow vacuum furnace to solve the problem of large impact and poor heat dissipation uniformity in the wafer reflow cooling process in the prior art.

[0004] The utility model provides a wafer reflow vacuum furnace, including second preheating area, welding area, third plug valve, cooling plate, gas bag, fourth plug valve, fifth plug valve, sixth plug valve and first cooling area, according to the work flow setting second preheating area, welding area and first cooling area, second preheating area import end setting third plug valve, second preheating area export end setting fourth plug valve, the import end of welding area setting fourth plug valve, the export end of welding area setting fifth plug valve, the import end of first cooling area setting fifth plug valve, the export end of first cooling area setting sixth plug valve, first cooling area inside setting cooling plate, cooling plate on setting gas bag, a plurality of first orifices are uniformly arranged in the gas bag.

[0005] According to the wafer reflow vacuum furnace of the utility model, the first cooling area further includes a cooling area upper cover, the cooling area upper cover includes a cooling area upper cover frame, an upper cover heat dissipation plate and a heat dissipation mechanism, the upper cover heat dissipation plate is arranged inside the cooling area upper cover frame, the heat dissipation mechanism is arranged inside the upper cover heat dissipation plate, and the upper cover heat dissipation plate is symmetrically and uniformly provided with second orifices.

[0006] The wafer reflow vacuum furnace further comprises a first plug valve, a second plug valve, a first preheating area and a replacement area, the first preheating area is a previous work area of the second preheating area, the replacement area is a previous work area of the first preheating area, the first preheating area is provided with the second plug valve at an inlet end, the first preheating area is provided with a third plug valve at an outlet end, the replacement area is provided with the first plug valve at an inlet end, and the replacement area is provided with the second plug valve at an outlet end.

[0007] The wafer reflow vacuum furnace further comprises a seventh plug valve and a second cooling area, the second cooling area is a next work area of the first cooling area, the second cooling area is provided with the sixth plug valve at an inlet end, and the second cooling area is provided with the seventh plug valve at an outlet end.

[0008] The wafer reflow vacuum furnace comprises a first preheating area, a second preheating area and a welding area, and the first preheating area, the second preheating area and the welding area comprise a first mounting frame, an upper cover, an upper heating pipe, a heating plate, a power wheel, a guide wheel and a lower heating pipe.

[0009] The wafer reflow vacuum furnace comprises a first preheating area, a second preheating area and a welding area, and the first preheating area, the second preheating area and the welding area comprise a first mounting frame, an upper cover, an upper heating pipe, a heating plate, a power wheel, a guide wheel and a lower heating pipe.

[0010] The wafer reflow vacuum furnace further comprises a small wafer and a non-contact temperature measuring sensor, the first preheating area, the second preheating area and the welding area are provided with the small wafer and the contact or non-contact temperature measuring sensor, and the small wafer is arranged in a detection range of the non-contact temperature measuring sensor.

[0011] The wafer reflow vacuum furnace further comprises a first preheating area, a second preheating area and a welding area, and the first preheating area, the second preheating area and the welding area comprise a first mounting frame, an upper cover, an upper heating pipe, a heating plate, a power wheel, a guide wheel and a lower heating pipe.

[0012] The wafer reflow vacuum furnace further comprises a first preheating area, a second preheating area and a welding area, and the first preheating area, the second preheating area and the welding area comprise a first mounting frame, an upper cover, an upper heating pipe, a heating plate, a power wheel, a guide wheel and a lower heating pipe.

[0013] The wafer reflow vacuum furnace further comprises an inner container, the first preheating zone, the second preheating zone and the welding zone are arranged in the inner container, and the upper heating pipe and the lower heating pipe are arranged inside the inner container.

[0014] The wafer reflow vacuum furnace has the following advantages.

[0015] 1. The length of the notch length L is greater than the width of the power wheel, and the length of the notch length L is less than 1.5 times the width of the power wheel, the distance between the notch edge of the wafer tray and the edge of the power wheel is less than 0.5 times the width of the power wheel, and the distance between the power wheels is less than or equal to 1 / 4 of the length of the wafer tray. Before the wafer tray tilts and clamps, the adjustment is carried out to prevent the clamping from occurring.

[0016] 2. The distance between the upper heating pipe and the wafer is equal to the distance between the lower heating pipe and the wafer, non-contact heating or welding is carried out, the same temperature and uniform temperature of the upper and lower surfaces of the wafer are ensured, and the heating uniformity of the upper and lower surfaces of the wafer is improved.

[0017] 3. The upper cover heat dissipation plate is provided with a plurality of symmetrical second fine holes, so that the airflow is more concentrated and directional, and the airflow can be accurately blown to the key parts on the upper surface of the wafer after being blown out through the fine holes, the specificity of heat dissipation is improved, and the heat is more effectively taken away.

[0018] 4. The air bag is provided with a plurality of symmetrical first fine holes, so that the cooling gas can be uniformly sprayed on the lower surface of the wafer, and the non-uniform heat dissipation is avoided. The impact force of the airflow is dispersed, the airflow is blown out gently from the plurality of first fine holes, and the wafer is not damaged by logistics, especially for high-precision and easily damaged. The contact area of the gas on the wafer surface is increased, the heat dissipation process is more sufficient, and the temperature of the wafer is rapidly reduced.

[0019] 5. Small wafers are arranged for temperature control, and a contact sensor or a non-contact sensor directly measures the temperature of the small wafers. Since the small wafers and the wafers are made of the same material, the same temperature of the small wafers and the wafers is achieved, and the temperature control accuracy is improved.

[0020] 6. The inner container adopts a single-side mirror plate, and the heat reflection and heat insulation effects are good.

[0021] 7. The replacement zone is vacuumized at room temperature to prevent oxidation in the first preheating zone and affect the wafer reflow quality. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0023] Figure 1 It is a schematic view of the structure of the front view of the vacuum furnace.

[0024] Figure 2 It is a schematic view of the structure of the perspective view of the vacuum furnace.

[0025] Figure 3 It is a schematic view of the structure of the sectional view of the welding area.

[0026] Figure 4 It is a schematic view of the structure of the lower cavity of the welding area.

[0027] Figure 5 It is a schematic view of the structure of the perspective view of the wafer tray.

[0028] Figure 6 It is a schematic view of the structure of the front view of the wafer tray.

[0029] Figure 7 It is Figure 4 It is a schematic view of the structure of the enlarged view of A in the middle.

[0030] Figure 8 It is Figure 6 It is a schematic view of the structure of the enlarged view of B in the middle.

[0031] Figure 9 It is a schematic view of the structure of the lower cavity perspective view of the first cooling area.

[0032] Figure 10 It is a schematic view of the structure of the upper cover perspective view of the first cooling area.

[0033] Figure 11 It is a schematic view of the structure of the sectional view of the upper cover of the first cooling area.

[0034] Reference numerals: 1, replacement area; 2, first preheating area; 3, second preheating area; 4, welding area; 5, first cooling area; 6, second cooling area; 7, plug valve; 8, lifting mechanism; 9, wafer tray; 41, upper heating pipe; 42, lower heating pipe; 43, first mounting frame; 44, small wafer; 45, heating plate; 46, power wheel; 47, guide wheel; 48, power wheel width; 49, power wheel spacing; 50, inner container; 51, second mounting frame; 52, cooling plate; 53, air bag; 54, second nitrogen pipe; 55, cooling area upper cover frame; 56, upper cover heat sink; 57, motor; 91, tray frame; 92, support leg; 93, notch length L; 94, tray length; 95, notch; 96, material taking notch; 411, first nitrogen pipe; 412, first nitrogen pipe port. DETAILED DESCRIPTION

[0035] The embodiments of the present application will be further described below in conjunction with the drawings and examples. The following examples are used to illustrate the present application, but cannot be used to limit the scope of the present application.

[0036] In the description of the embodiments of the present application, it should be explained that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0037] In the description of the embodiments of the present application, it should be explained that, unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0038] In the embodiments of the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact of the first and second features, or indirect contact of the first and second features through an intermediate medium.

[0039] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples without contradiction.

[0040] The following will be described in combination with Figures 1-11 A wafer reflow vacuum furnace is described in the embodiments of the present application, including a second preheating zone 3, a welding zone 4, a cooling plate 52, a gas bag 53, a third plug valve, a fourth plug valve, a fifth plug valve, a sixth plug valve and a first cooling zone 5; The second preheating zone 3, the welding zone 4 and the first cooling zone 5 are set according to the working process, the third plug valve is arranged at the inlet end of the second preheating zone 3, the fourth plug valve is arranged at the outlet end of the second preheating zone 3, the fourth plug valve is arranged at the inlet end of the welding zone 4, the fifth plug valve is arranged at the outlet end of the welding zone 4, the fifth plug valve is arranged at the inlet end of the first cooling zone 5, the sixth plug valve is arranged at the outlet end of the first cooling zone 5, the cooling plate 52 is arranged inside the first cooling zone 5, the gas bag 53 is arranged on the cooling plate 52, a plurality of first fine holes are symmetrically and uniformly arranged on the gas bag 53, the wafer tray 9 is arranged inside the second preheating zone 3, the welding zone 4 and the first cooling zone 5, and the supporting leg 92 of the wafer tray 9 supports the wafer. The surface of the supporting leg 92 supporting the wafer is a circular arc structure, which reduces the contact between the supporting leg 92 and the wafer and reduces the temperature influence of the supporting leg 92 on the wafer. The supporting leg 92 limits the wafer, the middle supporting leg 92 is short, and the two side supporting legs 92 are long, which limits the movement of the wafer. The positive pressure resistant vacuum plug valve, the furnace cavity sealing structure is designed with a locking device, the furnace cavity can resist positive pressure, the amount of reducing gas filled can be more, and the reduction is better. The second nitrogen pipe 54 fills nitrogen into the gas bag 53, and the nitrogen is discharged from the first fine hole to cool the wafer.

[0041] In some embodiments, the first cooling zone 5 further comprises a cooling zone upper cover, which comprises a cooling zone upper cover frame 55, an upper cover heat sink 56 and a heat dissipation mechanism 57; the heat dissipation mechanism is preferably a fan driven by a motor 57. The upper cover heat sink 56 is arranged inside the cooling zone upper cover frame 55, and the heat dissipation mechanism 57 is arranged inside the upper cover heat sink 56. The upper cover heat sink 56 is symmetrically and uniformly provided with second fine holes.

[0042] In some embodiments, the first plug valve, the second plug valve 7, the first preheating zone 2 and the replacement zone 1 are further included. The first preheating zone 2 is the previous work zone of the second preheating zone 3, and the replacement zone 1 is the previous work zone of the first preheating zone 2. The second plug valve 7 is arranged at the inlet end of the first preheating zone 2, the third plug valve is arranged at the outlet end of the first preheating zone 2, the first plug valve is arranged at the inlet end of the replacement zone 1, and the second plug valve 7 is arranged at the outlet end of the replacement zone 1. The replacement zone 1 is vacuumed at room temperature to prevent oxidation and affect the quality of wafer reflow when entering the first preheating zone 2.

[0043] The replacement zone 1 provides a vacuum environment, an inert gas environment or a reducing gas environment;

[0044] The first preheating zone 2 provides a vacuum environment, an inert gas environment or a reducing gas environment; the second preheating zone 3 provides a vacuum environment, an inert gas environment or a reducing gas environment;

[0045] The welding zone 4 provides a vacuum environment, an inert gas environment or a reducing gas environment.

[0046] The inert gas is preferably nitrogen. The reducing gas is preferably formic acid.

[0047] In some embodiments, the seventh plug valve and the second cooling zone 6 are further included. The second cooling zone 6 is the next work zone of the first cooling zone 5. The sixth plug valve is arranged at the inlet end of the second cooling zone 6, and the seventh plug valve is arranged at the outlet end of the second cooling zone 6. The above work zones are filtered at the same time when being vacuumed.

[0048] In some embodiments, the first preheating zone 2, the second preheating zone 3 and the welding zone 4 comprise a first mounting frame 43, an upper cover, an upper heating pipe 41, a heating plate 45, a power wheel 46, a guide wheel 47 and a lower heating pipe 42; the heating plate 45 is arranged inside the first mounting frame 43, the power wheel 46 and the guide wheel 47 are arranged on both sides of the heating plate 45, the lower heating pipe 42 is arranged below the heating plate 45, the upper heating pipe 41 is arranged inside the upper cover, the upper cover is arranged above the first mounting frame 43, and the upper cover and the first mounting frame 43 form a sealed cavity. The lower cavity of the first preheating zone 2, the second preheating zone 3 and the welding zone 4 comprises the first mounting frame 43, the heating plate 45, the power wheel 46, the guide wheel 47 and the lower heating pipe 42. Nitrogen pipes 411 are arranged around the upper part of the inside of the first mounting frame 43, a plurality of nitrogen pipe openings 412 are arranged on the nitrogen pipes 411, and the nitrogen pipe openings 412 are arranged to be inclined upward, thereby reducing the impact of nitrogen on the cavity, that is, reducing the impact of nitrogen on the wafer, and improving the welding quality of the wafer.

[0049] In some embodiments, the distance between the upper heating pipe 41 and the wafer tray 9 is equal to the distance between the lower heating pipe 42 and the wafer tray 9. The wafer is placed on the wafer tray 9, thereby ensuring that the distance between the upper heating pipe 41 and the wafer is equal to the distance between the lower heating pipe 42 and the wafer, and non-contact heating or welding is performed, that is, the temperature uniformity of the upper and lower surfaces of the wafer is improved, and the heating uniformity of the upper and lower surfaces of the wafer is improved.

[0050] In some embodiments, a small wafer 44 and a contact or non-contact temperature sensor are further included, and the first preheating zone 2, the second preheating zone 3 and the welding zone 4 are provided with the small wafer 44 and the contact or non-contact temperature sensor, and the small wafer 44 is arranged within the detection range of the contact or non-contact temperature sensor. The contact or non-contact temperature sensor is arranged above the upper cover, that is, outside the cavity, and a temperature measurement window is arranged. The small wafer 44 is arranged for temperature control, and the infrared sensor directly measures the temperature of the small wafer 44. Since the small wafer 44 and the wafer are made of the same material, the same temperature of the small wafer 44 and the wafer is achieved, and the temperature control accuracy is improved. The non-contact temperature sensor is preferably an infrared temperature sensor.

[0051] In some embodiments, the wafer tray 9 further comprises a tray frame 91 and a notch 95; the notch 95 is arranged on both sides of the tray frame 91 in the conveying direction, and the supporting legs 92 are arranged on both sides of the inside of the tray frame. The supporting legs 92 support the wafer. The supporting legs 92 are made of quartz, which does not absorb heat and does not affect the temperature of the wafer, thereby improving the wafer reflow quality. The power wheel 46 supports the transmission within the notch 95. The upper baffle plate is arranged below the upper heating pipe 41, and the upper baffle plate shields the upper heating pipe 41, so that the upper heating pipe 41 can only heat the upper surface of the wafer. The lower baffle plate is arranged above the lower heating pipe 42, and the lower baffle plate shields the lower heating pipe 42, so that the lower heating pipe 42 can only heat the lower surface of the wafer. The upper baffle plate is arranged to reduce the temperature influence of the upper heating pipe 41 on the lower surface of the wafer, and the lower baffle plate is arranged to reduce the temperature influence of the lower heating pipe 42 on the upper surface of the wafer, thereby achieving non-contact heating or welding, that is, achieving the simultaneous heating or welding of the upper surface and the lower surface of the wafer. The material taking notch 96 is arranged on the tray frame 91 in the direction of the transmission in and out, which facilitates the wafer taking of the robot.

[0052] In some embodiments, the notch length L93 of the notch 95 is greater than the width 48 of the power wheel, and the notch length L93 of the notch 95 is less than 1.5 times the width 48 of the power wheel, which is to prevent the wafer tray from tilting during the conveying process. The distance between the edge of the notch 95 and the edge of the power wheel 46 is less than 0.5 times the width 48 of the power wheel, and the distance between the power wheels 46 is less than or equal to 1 / 4 of the length 94 of the wafer tray, which is to prevent the wafer tray from tilting and clamping the plate before the adjustment is made, thereby preventing the clamping of the plate.

[0053] In some embodiments, the inner container 50 is further arranged in the first preheating area 2, the second preheating area 3 and the welding area 4, and the upper heating pipe 41 and the lower heating pipe 42 are arranged inside the inner container 50. The inner container 50 is a rectangular parallelepiped fixed on the upper cover or the first mounting frame 43. The inner container 50 adopts a single-sided mirror plate, has good heat reflection and heat insulation effects, reduces the heating time, and improves the wafer reflow efficiency.

[0054] The working process of the wafer reflow vacuum furnace is as follows:

[0055] The wafer robot grasps the first wafer, the replacement area 1 is opened, the transmission mechanism of the replacement area 1 drives the power wheel 46 to transmit, and the first wafer enters the replacement area 1; the plug valve 7 at the inlet end of the replacement area 1 is closed, and the replacement area 1 is vacuumized and then filled with nitrogen and formic acid mixed gas.

[0056] The first preheating area 2, the second preheating area 3, the welding area 4, the first cooling area 5 and the second cooling area 6 are vacuumized and then filled with nitrogen and formic acid mixed gas.

[0057] The inlet end plug valve 7 of the first preheating area 2 is opened, and the first wafer enters the first preheating area 2.

[0058] After the first wafer reaches the preheating standard, the second preheating area 3 is opened, the transmission mechanism drives the power wheel 46 to transmit, and the first wafer enters the second preheating area 3; the second preheating area 3 is closed, nitrogen is supplemented and replaced and formic acid is filled according to requirements, and the heater starts to work.

[0059] After the first wafer reaches the heating standard, the second preheating area 3 is opened, the transmission mechanism drives the power wheel 46 to transmit, and the first wafer enters the welding area 4; the welding area 4 is closed, nitrogen is supplemented and replaced and formic acid is filled according to requirements, and then welding is performed.

[0060] After the first wafer is processed, the welding area 4 is opened, the transmission mechanism drives the power wheel 46 to transmit, and the first wafer enters the first cooling area 5; the first cooling area 5 is closed, and the cooling device starts to work. After precooling reaches the standard, the second cooling area 6 is entered, and the process is the same as that of the precooling area, and the temperature reaches room temperature;

[0061] After cooling is completed, the wafer is transmitted to the outlet area, and the wafer is taken out by the mechanical arm. Then the next cycle is entered;

[0062] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A wafer reflow vacuum furnace, characterized by, The first cooling zone further comprises a cooling zone upper cover, and the cooling zone upper cover comprises a cooling zone upper cover frame, an upper cover heat dissipation plate and a heat dissipation mechanism; the cooling zone upper cover frame is internally provided with the upper cover heat dissipation plate, and the upper cover heat dissipation plate is internally provided with the heat dissipation mechanism; and the upper cover heat dissipation plate is symmetrically and uniformly provided with second fine holes.

2. The wafer reflow vacuum furnace according to claim 1, wherein, The first cooling zone further comprises a cooling zone upper cover, and the cooling zone upper cover comprises a cooling zone upper cover frame, an upper cover heat dissipation plate and a heat dissipation mechanism; the cooling zone upper cover frame is internally provided with the upper cover heat dissipation plate, and the upper cover heat dissipation plate is internally provided with the heat dissipation mechanism; and the upper cover heat dissipation plate is symmetrically and uniformly provided with second fine holes.

3. The wafer reflow vacuum furnace of claim 1, wherein, The first preheating zone, the second preheating zone and the welding zone further comprise a first installation frame, an upper cover, an upper heating pipe, a heating plate, a power wheel, a guide wheel and a lower heating pipe; the heating plate is arranged in the interior of the first installation frame, the power wheel and the guide wheel are arranged on the two sides of the heating plate, the lower heating pipe is arranged below the heating plate, the upper heating pipe is arranged in the interior of the upper cover, the upper cover is arranged above the first installation frame, and the upper cover and the first installation frame form a sealed cavity.

4. The wafer reflow vacuum furnace of claim 3, wherein, The distance between the upper heating pipe and the wafer tray is equal to the distance between the lower heating pipe and the wafer tray.

5. The wafer reflow vacuum furnace of claim 4, wherein, The first preheating zone, the second preheating zone and the welding zone are further provided with a small wafer and a non-contact temperature measuring sensor; and the small wafer is arranged in the detection range of the non-contact temperature measuring sensor.

6. The wafer reflow vacuum furnace of claim 5, wherein, The wafer tray further comprises a tray frame, a support leg and a notch; the notch is arranged on the two sides of the tray frame in the conveying direction, and the support leg is arranged in the interior of the tray frame on the two sides.

7. The wafer reflow vacuum furnace of claim 4, wherein, ​ 8. The wafer reflow vacuum furnace of claim 5, wherein, ​ 9. The wafer reflow vacuum furnace of claim 8, wherein, The gap length L of the gap is greater than the width of the power wheel, the gap length L of the gap is less than 1.5 times the width of the power wheel, the distance between the edge of the gap and the edge of the power wheel is less than 0.5 times the width of the power wheel, and the distance between the power wheels is less than or equal to 1 / 4 of the wafer tray length.

10. The wafer reflow vacuum furnace of claim 5, wherein, Further comprising an inner container, the first preheating zone, the second preheating zone and the welding zone are arranged in the inner container, and the upper heating pipe and the lower heating pipe are arranged inside the inner container.

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