Method for improving temperature uniformity of heating plate and vacuum welding furnace for chip packaging

Abstract

The invention relates to the technical field of packaging and welding, and provides a method for improving the temperature uniformity of a heating plate and a vacuum welding furnace for chip packaging. The flow guide cover is arranged in the vacuum welding furnace, the air uniformizing plate is arranged in an upper cavity of the vacuum welding furnace, the upper infrared heating pipe is arranged above the air uniformizing plate, at least one fan is arranged above the upper infrared heating pipe, and the fan, the air uniformizing plate and the upper infrared heating pipe are arranged in the flow guide cover. The distance between the air uniformizing plate and the upper infrared heating pipe is set to be a first distance L1; the distance between the air uniformizing plate and the heating plate is set to be a second distance L2. And the temperature uniformity of the heating plate is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of chip processing equipment, and in particular to a method for improving the temperature uniformity of a heating plate and a vacuum welding furnace for chip packaging. Background Art

[0002] Vacuum soldering furnaces provide a clean, stable environment for chip packaging, ensuring chip quality, performance, and reliability. For example, a vacuum eutectic furnace utilizes a vacuum chamber, placing the chip on a heating plate within the chamber. The heating plate heats and cools the chip, completing the soldering process. However, existing vacuum soldering furnaces suffer from poor temperature uniformity on the heating plate. Summary of the Invention

[0003] The present invention provides a method for improving the temperature uniformity of a heating plate, which is used to solve the problem of temperature uniformity of a heating plate of a vacuum welding furnace in the prior art.

[0004] A method for improving temperature uniformity of a heating plate, comprising: The air guide cover is arranged inside the vacuum welding furnace, the air uniform plate is arranged inside the upper cavity of the vacuum welding furnace, the upper infrared heating tube is arranged above the air uniform plate, at least one fan is arranged above the upper infrared heating tube, and the fan, the air uniform plate and the upper infrared heating tube are arranged inside the air guide cover; Set the distance between the air uniform plate and the upper infrared heating tube to a first distance L1; The distance between the air uniforming plate and the heating plate is set to a second distance L2.

[0005] The method for improving the temperature uniformity of a heating plate according to the present invention further includes: setting the opening ratio of the central area of ​​the air uniforming plate to a first opening ratio, setting the opening ratio of the transition area of ​​the air uniforming plate to a second opening ratio, and setting the opening ratio of the edge area of ​​the air uniforming plate to a third opening ratio. The method for improving the temperature uniformity of a heating plate according to claim 2 is characterized by further including: using a central single fan when the length of the vacuum welding furnace is less than 1.2m, and using distributed fans at four corners when the length of the vacuum welding furnace is greater than 1.2m.

[0006] According to the method for improving the temperature uniformity of the heating plate of the present invention, if four-corner distributed fans are used, the first fan and the second fan are symmetrically arranged on the top of the vacuum soldering furnace, and the third fan and the fourth fan are symmetrically arranged on the side.

[0007] According to the method for improving the temperature uniformity of the heating plate of the present invention, the radial components of the third fan and the fourth fan are 10-15°, and the tangential components of the third fan and the fourth fan are 6-8°.

[0008] According to the method for improving the temperature uniformity of the heating plate of the present invention, the first spacing L1 is ≥ 20d+0.05D1, d: aperture of the air uniform plate, D1: average length and width of the air uniform plate.

[0009] According to the method for improving the temperature uniformity of a heating plate of the present invention, the minimum value of the first distance L1 is 95-105 mm, and the maximum value of the first distance L1 is 0.2D1.

[0010] According to the method for improving the temperature uniformity of the heating plate of the present invention, the second distance L2=0.1~0.15×D2+∆H, D2: average length and width of the heating plate, ∆H: structural compensation height.

[0011] According to the method for improving the temperature uniformity of a heating plate of the present invention, the first opening ratio is 25-35%, the second opening ratio is 35-45%, and the third opening ratio is 45-55%.

[0012] A vacuum soldering furnace for chip packaging, the vacuum soldering furnace for chip packaging is used to execute any of the methods described above, the vacuum soldering furnace for chip packaging comprises an upper cavity, a lower cavity, an upper heating tube, a fan, a heating plate and a guide cover, the upper cavity is arranged above the lower cavity, the upper cavity and the lower cavity form a vacuum cavity, the guide cover is arranged inside the upper cavity, the upper infrared heating tube is arranged above the air uniforming plate, at least one fan is arranged above the upper infrared heating tube, the fan, the air uniforming plate and the upper infrared heating tube are arranged inside the guide cover.

[0013] The present invention uses the first spacing L1 to provide mixing space for the airflow, allowing the hot jet to fully diffuse and achieve uniform velocity. L1 has a minimum value of 100 mm to prevent the hot jet from impacting the infrared heating tubes before mixing. The maximum value of L1 is 0.2D1 to avoid excessive kinetic energy loss. The second spacing L2 ensures that the hot air evenly covers the surface of the heating plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 Schematic diagram of the process for improving the temperature uniformity of the heating plate; Figure 2 It is a schematic diagram of the three-dimensional structure of a vacuum welding furnace; Figure 3 A schematic diagram of the three-dimensional structure of the lower cavity Figure 1 ; Figure 4 A schematic diagram of the three-dimensional structure of the lower cavity Figure 2 ; Figure 5 Schematic diagram of the three-dimensional structure of the upper cavity; Figure 6 Schematic diagram of the cross-sectional structure of the upper cavity; Figure numerals: 1. upper cavity; 2. lower cavity; 3. support structure; 4. roller; 5. alarm light; 11. upper cavity frame; 12. upper heating tube; 13. air uniforming plate; 14. cooling tube fin; 15. fan; 16. fan motor; 17. air guide cover; 21. lower cavity frame; 22. support column; 23. nitrogen pipe; 24. lower heating tube; 25. heating plate; 26. cooling tube. DETAILED DESCRIPTION

[0016] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0017] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0018] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; and direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on the specific circumstances.

[0019] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," or "above" a second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," or "below" a second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0020] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or at least one embodiment or example in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0021] The following combination Figure 1 A method for improving the temperature uniformity of a heating plate according to an embodiment of the present invention is described, comprising: S101. The air guide hood is arranged inside the vacuum welding furnace, the air uniform plate is arranged inside the upper cavity 1 of the vacuum welding furnace, the upper infrared heating tube 12 is arranged above the air uniform plate, the upper heating tube 12 is preferably an upper infrared heating tube 12, and at least one fan 15 is arranged above the upper infrared heating 12. The fan 15, the air uniform plate 13 and the upper infrared heating tube 12 are arranged inside the air guide hood 17.

[0022] S102. Set the distance between the air leveling plate and the upper infrared heating tube to a first distance L1, where L1 is ≥ 20d + 0.05D1, where d is the air leveling plate aperture and D1 is the average of the length and width of the air leveling plate. This provides mixing space for the airflow, allowing the heat jet to fully diffuse and achieve uniform velocity. The minimum value of L1 is 100 mm to prevent the heat jet from impacting the upper infrared heating tube before mixing. The maximum value of L1 is 0.2D1 to avoid excessive kinetic energy loss in the heat jet.

[0023] S103. Set the distance between the air distribution plate and the heating plate to the second distance, L2. L2 = 0.1-0.15 × D2 + ∆H, where D2 is the average length and width of the heating plate, and ∆H is the structural compensation height (including the thickness of the heating tube, preferably 50-100 mm). Ensure that hot air evenly covers the surface of the heating plate. L2 should be ≥ 150 mm to avoid dead zones. Deflector skirts (inclined 15-30 degrees) should be installed at the edges of the heating plate to prevent airflow separation at the edges.

[0024] S104. Set the opening rate of the central area of ​​the wind uniform plate to the first opening rate, the first opening rate is 25-35%, the radius of the central area is ≤0.3R, low density and large spacing, suppressing the central high-speed area; set the opening rate of the transition area of ​​the wind uniform plate to the second opening rate, the second opening rate is 35-45%, 0.3R ≤ transition area radius ≤0.7R, medium density, and smooth flow rate transition; set the opening rate of the edge area of ​​the wind uniform plate to the third opening rate, the third opening rate is 45-55%, the edge area radius is >0.7R, high density, small spacing, to compensate for wall resistance loss. Increase the proportion of airflow flowing to the edge area, compensate for its natural attenuation, and obtain more uniform wind speed coverage for the entire heating area. The aperture is preferably 3-8mm. Small holes can produce more and more dispersed jets, which helps to mix and homogenize the airflow faster under the wind uniform plate.

[0025] S105. When the length of the vacuum welding furnace is less than 1.2m, a central single fan is used. When the length of the vacuum welding furnace is greater than 1.2m, four-corner distributed fans are used to eliminate the low-temperature area at the edge of the heating plate and reduce the temperature difference.

[0026] S106. If four-corner distributed fans are used, the first fan and the second fan are symmetrically arranged on the top of the vacuum welding furnace, and the third fan and the fourth fan are symmetrically arranged on the side. The radial component of the third fan and the fourth fan has a vertical velocity gain of 10-15°, which penetrates the boundary layer and pushes the airflow to the edge of the heating plate. The tangential component of 6-8° induces circumferential velocity, generates forced vortex, and eliminates flow dead zones.

[0027] like Figure 2-6 The present invention describes an embodiment of a vacuum soldering furnace for chip packaging, comprising an upper cavity 1, a lower cavity 2, at least one cooling tube, at least one upper heating tube 12, an air-applying mechanism, an air-distributing plate 13, and a heating plate 25; the upper cavity 1 is arranged above the lower cavity 2, and the upper cavity 1 and the lower cavity 2 form a vacuum cavity, the upper heating tube 12 is arranged inside the upper cavity 1, the cooling tube is arranged inside the lower cavity 2, the cooling tube is embedded below the heating plate 25, and the cooling tube is supported by a cooling tube support column 22. A support structure 3 is provided in the lower cavity 2, rollers 4 are provided around the bottom of the support structure 3, and an alarm light 5 is provided above the support structure. If infrared temperature measurement is used, an infrared temperature measurement mechanism is provided on the top of the upper cavity 1, and infrared temperature measurement holes are provided at corresponding positions of the air-distributing plate 13 and the air guide cover 17.

[0028] The air leveling plate 13 is a quartz glass plate and is evenly provided with multiple holes. This improves temperature uniformity and can evenly guide the airflow, eliminating local turbulence, ensuring uniformity during the heating phase and preventing deformation of the workpiece caused by uneven heating.

[0029] The air supply mechanism further includes a shroud 17 and cooling tube fins 14. The fan 15 and cooling tube fins 14 of the air supply mechanism are disposed within the shroud 17, with the cooling tube fins 14 disposed below the air supply mechanism. The air supply mechanism further includes a fan motor 16; fan motor 16 is disposed at the top of the upper chamber 1, and fan 15 is disposed within the upper chamber 1. Fan motor 16 drives fan 15.

[0030] The lower cavity 2 includes a lower cavity frame 21 , a nitrogen pipe 23 and a protective plate; a heating plate 25 is arranged inside the lower cavity frame 21 , protective plates are arranged on both sides of the heating plate 25 , and the nitrogen pipe 23 is arranged below the heating plate 25 .

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for improving the temperature uniformity of a heating plate, characterized in that: include: The air guide cover is arranged inside the vacuum welding furnace, the air uniform plate is arranged inside the upper cavity of the vacuum welding furnace, the upper infrared heating tube is arranged above the air uniform plate, at least one fan is arranged above the upper infrared heating tube, and the fan, the air uniform plate and the upper infrared heating tube are arranged inside the air guide cover; Set the distance between the air uniform plate and the upper infrared heating tube to a first distance L1; The distance between the air uniforming plate and the heating plate is set to a second distance L2.

2. The method for improving the temperature uniformity of a heating plate according to claim 1, characterized in that: Also includes: The opening rate of the central area of ​​the air uniform plate is set to the first opening rate, the opening rate of the transition area of ​​the air uniform plate is set to the second opening rate, and the opening rate of the edge area of ​​the air uniform plate is set to the third opening rate.

3. The method for improving the temperature uniformity of a heating plate according to claim 2, characterized in that: Also includes: When the length of the vacuum welding furnace is less than 1.2m, a central single fan is used. When the length of the vacuum welding furnace is greater than 1.2m, four-corner distributed fans are used.

4. The method for improving the temperature uniformity of a heating plate according to claim 3, characterized in that: If four-corner distributed fans are used, the first fan and the second fan are symmetrically arranged on the top of the vacuum soldering furnace, and the third fan and the fourth fan are symmetrically arranged on the side.

5. The method for improving the temperature uniformity of a heating plate according to claim 4, characterized in that: The radial components of the third fan and the fourth fan are 10-15°, and the tangential components of the third fan and the fourth fan are 6-8°.

6. The method for improving the temperature uniformity of a heating plate according to claim 1, wherein: The first spacing L1 is ≥ 20d+0.05D1, where d is the aperture of the air uniform plate, and D1 is the average length and width of the air uniform plate.

7. The method for improving the temperature uniformity of a heating plate according to claim 6, characterized in that: The minimum value of the first distance L1 is 95-105 mm, and the maximum value of the first distance L1 is 0.2D1.

8. The method for improving the temperature uniformity of a heating plate according to claim 1, wherein: The second spacing L2=0.1~0.15×D2+∆H, D2: average length and width of the heating plate, ∆H: structural compensation height.

9. The method for improving the temperature uniformity of a heating plate according to claim 2, wherein: The first opening ratio is 25-35%, the second opening ratio is 35-45%, and the third opening ratio is 45-55%.

10. A vacuum soldering furnace for chip packaging, characterized in that: The vacuum soldering furnace for chip packaging is used to execute the method described in any one of claims 1 to 9 above, and the vacuum soldering furnace for chip packaging includes an upper cavity, a lower cavity, an upper heating tube, a fan, a heating plate and an air guide cover. The upper cavity is arranged above the lower cavity, and the upper cavity and the lower cavity form a vacuum cavity. The air guide cover is arranged inside the upper cavity, the upper infrared heating tube is arranged above the air uniformity plate, and at least one fan is arranged above the upper infrared heating tube. The fan, the air uniformity plate and the upper infrared heating tube are arranged inside the air guide cover.

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