Method for improving temperature uniformity of a hot plate and vacuum soldering furnace for chip packaging

Abstract

The application relates to the technical field of packaging welding, and provides a method for improving temperature uniformity of a heating plate and a vacuum welding furnace for chip packaging. A flow guide cover is arranged in the interior of the vacuum welding furnace, an air uniformizing plate is arranged in the upper cavity of the vacuum welding furnace, an 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 interior of the flow guide cover; the interval between the air uniformizing plate and the upper infrared heating pipe is set as a first interval L1; and the interval between the air uniformizing plate and the heating plate is set as a second interval L2. The temperature uniformity of the heating plate is improved.

Description

Technical Field

[0001] This invention relates to the field of chip processing equipment technology, and in particular to a method for improving the temperature uniformity of a heating plate and a vacuum soldering furnace for chip packaging. Background Technology

[0002] Vacuum soldering furnaces provide a clean and stable environment for chip packaging, ensuring chip quality, performance, and reliability. Taking a vacuum eutectic furnace as an example, it uses a vacuum chamber where the chip is placed on a heating platform. The chip is soldered using the heating and cooling processes of the heating plates. However, existing vacuum soldering furnaces suffer from poor temperature uniformity in their heating plates. Summary of the Invention

[0003] This invention provides a method for improving the temperature uniformity of a heating plate, thereby solving the problem of temperature uniformity of the heating plate in a vacuum welding furnace in the prior art.

[0004] A method for improving the temperature uniformity of a heating plate includes:

[0005] The flow guide shroud is installed inside the vacuum welding furnace, the air distribution plate is installed inside the upper cavity of the vacuum welding furnace, the upper infrared heating tube is installed above the air distribution plate, and at least one fan is installed above the upper infrared heating tube. The fan, the air distribution plate and the upper infrared heating tube are installed inside the flow guide shroud.

[0006] Set the distance between the air distribution plate and the upper infrared heating tube to the first distance L1;

[0007] Set the distance between the air distribution plate and the heating plate to the second distance L2.

[0008] 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 distribution plate to a first opening ratio, setting the opening ratio of the transition area of ​​the air distribution plate to a second opening ratio, and setting the opening ratio of the edge area of ​​the air distribution plate to a third opening ratio. It 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.

[0009] According to the method for improving the temperature uniformity of the heating plate of the present invention, if a four-corner distributed fan is used, a first fan and a second fan are symmetrically arranged at the top of the vacuum welding furnace, and a third fan and a fourth fan are symmetrically arranged on the side.

[0010] According to the method for improving the temperature uniformity of the heating plate of the present invention, the radial components of the third and fourth fans are 10-15°, and the tangential components of the third and fourth fans are 6-8°.

[0011] According to the method for improving the temperature uniformity of the heating plate of the present invention, the first spacing L1 ≥ 20d + 0.05D1, where d is the aperture of the air distribution plate and D1 is the average length and width of the air distribution plate.

[0012] According to the method for improving the temperature uniformity of the heating plate of the present invention, the minimum value of the first spacing L1 is 95-105mm, and the maximum value of the first spacing L1 is 0.2D1.

[0013] According to the method for improving the temperature uniformity of the heating plate of the present invention, the second spacing 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.

[0014] According to the method for improving the temperature uniformity of the 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%.

[0015] A vacuum soldering furnace for chip packaging is provided, wherein the vacuum soldering furnace for chip packaging is used to perform the method described in any of the preceding claims. The vacuum soldering furnace for chip packaging includes an upper cavity, a lower cavity, an upper heating tube, a fan, a heating plate, and a flow guide shroud. The upper cavity is disposed above the lower cavity, and the upper cavity and the lower cavity form a vacuum cavity. The flow guide shroud is disposed inside the upper cavity. The upper infrared heating tube is disposed above a uniform air distribution plate, and at least one fan is disposed above the upper infrared heating tube. The fan, the uniform air distribution plate, and the upper infrared heating tube are disposed inside the flow guide shroud.

[0016] This invention provides a mixing space for the airflow through a first spacing L1, allowing the hot jet to diffuse fully and its velocity to become uniform. The minimum value of L1 is 100mm to prevent the hot jet from impacting the infrared heating tube without mixing, and the maximum value of L1 is 0.2D1 to avoid excessive kinetic energy loss of the hot jet. The second spacing L2 ensures that the hot air evenly covers the surface of the heating plate. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of a method to improve the temperature uniformity of a heating plate; Figure 2 This is a three-dimensional structural schematic diagram of a vacuum welding furnace;

[0019] Figure 3 A three-dimensional structural diagram of the lower cavity. Figure 1 ;

[0020] Figure 4 A three-dimensional structural diagram of the lower cavity. Figure 2 ;

[0021] Figure 5 This is a three-dimensional structural diagram of the upper cavity;

[0022] Figure 6 This is a cross-sectional view of the upper cavity and a schematic diagram of its structure.

[0023] Reference 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 distribution plate; 14. Cooling tube fins; 15. Fan; 16. Fan motor; 17. Flow guide; 21. Lower cavity frame; 22. Support column; 23. Nitrogen pipe; 24. Lower heating tube; 25. Heating plate; 26. Cooling tube. Detailed Implementation

[0024] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0025] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0027] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0028] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or at least one embodiment or example. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0029] The following is combined Figure 1 An embodiment of the present invention describes a method for improving the temperature uniformity of a heating plate, comprising:

[0030] S101, the flow guide shroud is set inside the vacuum welding furnace, the air distribution plate is set inside the upper cavity 1 of the vacuum welding furnace, the upper infrared heating tube 12 is set above the air distribution plate, the upper heating tube 12 is preferably an upper infrared heating tube 12, at least one fan 15 is set above the upper infrared heating tube 12, and the fan 15, the air distribution plate 13 and the upper infrared heating tube 12 are set inside the flow guide shroud 17.

[0031] S102. Set the distance between the air distribution plate and the upper infrared heating tube to the first distance L1, where L1 ≥ 20d + 0.05D1, d: aperture of the air distribution plate, D1: average length and width of the air distribution plate. This provides mixing space for the airflow, allowing the heat jet to diffuse fully and its velocity to be uniform. The minimum value of L1 is 100mm to prevent the heat jet from impacting the upper infrared heating tube before mixing, and the maximum value of L1 is 0.2D1 to avoid excessive kinetic energy loss of the heat jet.

[0032] S103. Set the distance between the air distribution plate and the heating plate to the second distance L2, where L2 = 0.1~0.15×D2 + ∆H, D2: the average length and width of the heating plate, and ∆H: the structural compensation height (including the thickness of the heating tube, preferably 50~100mm) to ensure that the hot air evenly covers the surface of the heating plate. L2 ≥ 150mm to avoid airflow dead zones. Set the edge of the heating plate with a guide skirt (tilted at 15~30 degrees) to prevent airflow separation at the edge.

[0033] S104. The opening ratio of the central area of ​​the air distribution plate is set as the first opening ratio, which is 25-35%, with a central area radius ≤ 0.3R, low density, and large spacing to suppress the high-speed zone in the center. The opening ratio of the transition area of ​​the air distribution plate is set as the second opening ratio, which is 35-45%, with 0.3R ≤ transition area radius ≤ 0.7R, medium density, and smooth flow velocity transition. The opening ratio of the edge area of ​​the air distribution plate is set as the third opening ratio, which is 45-55%, with an edge area radius > 0.7R, high density, and small spacing to compensate for wall resistance loss. This increases the proportion of airflow towards the edge area, compensating for its natural attenuation, and enabling more uniform wind speed coverage throughout the heating area. The orifice diameter is preferably 3-8mm; smaller orifices can generate more and more dispersed jets, which helps to mix and homogenize the airflow more quickly below the air distribution plate.

[0034] 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 zone at the edge of the heating plate and reduce the temperature difference.

[0035] S106. If a four-corner distributed fan is used, the first and second fans are symmetrically arranged at the top of the vacuum welding furnace, and the third and fourth fans are symmetrically arranged on the side. The radial component of the third and fourth fans has a vertical velocity gain of 10-15°, which penetrates the boundary layer and pushes the airflow toward the edge of the heating plate. The tangential component has a 6-8° induced circumferential velocity, generating forced vortices and eliminating flow dead zones.

[0036] like Figure 2-6 This invention describes a vacuum soldering furnace for chip packaging, comprising an upper cavity 1, a lower cavity 2, at least one cooling pipe, at least one upper heating pipe 12, an air distribution mechanism, an air distribution plate 13, and a heating plate 25. The upper cavity 1 is positioned above the lower cavity 2, forming a vacuum cavity. The upper heating pipe 12 is disposed inside the upper cavity 1, and the cooling pipe is disposed inside the lower cavity 2, embedded below the heating plate 25. The cooling pipe is supported by cooling pipe support columns 22. The lower cavity 2 is provided with a support structure 3, with rollers 4 arranged around its lower perimeter, and an alarm light 5 positioned above the support structure. If infrared temperature measurement is used, an infrared temperature measurement mechanism is provided at the top of the upper cavity 1, and infrared temperature measurement holes are provided at corresponding positions on the air distribution plate 13 and the air guide shroud 17.

[0037] The air distribution plate 13 is a quartz glass plate with multiple holes evenly distributed on it. This improves temperature uniformity. The air distribution plate 13 can guide the airflow evenly, eliminate local turbulence, ensure uniformity during the heating stage, and avoid deformation caused by uneven heating of the workpiece.

[0038] It also includes a flow guide shroud 17 and cooling pipe fins 14. The fan 15 and cooling pipe fins 14 of the air-spraying mechanism are disposed inside the flow guide shroud 17, and the cooling pipe fins 14 are disposed below the air-spraying mechanism. The air-spraying mechanism also includes a fan motor 16; the fan motor 16 is disposed at the top of the upper cavity 1, and the fan 15 is disposed inside the upper cavity 1. The fan motor 16 drives the fan 15.

[0039] The lower cavity 2 includes a lower cavity frame 21, a nitrogen pipe 23, and a protective plate; a heating plate is installed inside the lower cavity frame 21.

[0040] Protective plates are provided on both sides of the heating plate 25, and the nitrogen pipe 23 is located below the heating plate 25.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for improving the temperature uniformity of a heating plate, characterized in that, include: The flow guide shroud is installed inside the vacuum welding furnace, the air distribution plate is installed inside the upper cavity of the vacuum welding furnace, the upper infrared heating tube is installed above the air distribution plate, and at least one fan is installed above the upper infrared heating tube. The fan, the air distribution plate and the upper infrared heating tube are installed inside the flow guide shroud. Set the distance between the air distribution plate and the upper infrared heating tube to the first distance L1; Set the distance between the air distribution plate and the heating plate to the second distance L2; It also includes: setting the opening rate of the center area of ​​the air distribution plate as a first opening rate, setting the opening rate of the transition area of ​​the air distribution plate as a second opening rate, and setting the opening rate of the edge area of ​​the air distribution plate as a third opening rate, wherein the radius of the center area is ≤0.3R, 0.3R ≤ the radius of the transition area is ≤0.7R, the first opening rate is 25-35%, the second opening rate is 35-45%, the radius of the edge area is >0.7R, and the third opening rate is 45-55%; It 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. If a four-corner distributed fan is used, the first and second fans are symmetrically arranged at the top of the vacuum welding furnace, and the third and fourth fans are symmetrically arranged on the side. The radial components of the third and fourth fans are 10-15°, and the tangential components of the third and fourth fans are 6-8°. The first spacing L1 ≥ 20d + 0.05D1, where d is the aperture of the air distribution plate and D1 is the average length and width of the air distribution plate. The minimum value of the first spacing L1 is 95-105mm, and the maximum value of the first spacing L1 is 0.2D1; The second spacing 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.

2. A vacuum soldering furnace for chip packaging, characterized in that, The vacuum soldering furnace for chip packaging is used to perform the method described in claim 1 above. The vacuum soldering furnace for chip packaging includes an upper cavity, a lower cavity, an upper heating tube, a fan, a heating plate, and a flow guide shroud. The upper cavity is disposed above the lower cavity, and the upper cavity and the lower cavity form a vacuum cavity. The flow guide shroud is disposed inside the upper cavity. The upper infrared heating tube is disposed above the air distribution plate, and at least one fan is disposed above the upper infrared heating tube. The fan, the air distribution plate, and the upper infrared heating tube are disposed inside the flow guide shroud.

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