A wafer chuck manufacturing process with excellent sealing performance

Abstract

The present application relates to wafer chuck technical field, specifically, it relates to a kind of wafer chuck manufacturing process with excellent sealing, comprising the following steps: S1.preparing panel;S2.on panel installs brazing material;S3.installing bottom plate;S4.vacuum brazing is carried out;S5.brazing heat treatment, obtain wafer chuck.The present application applies vacuum brazing technology to wafer chuck, compared with existing adhesive technology, the present application utilizes specific ratio of lead solder and brazing temperature, can make wafer chuck more stable in adsorbing wafer, conducive to the detection of wafer later.In the manufacturing process of the present application, brazing heat treatment process step is also designed, by designing the step, the adhesion ability of aluminum alloy during vacuum brazing can be enhanced.The vacuum brazing technology in the present application can simultaneously realize brazing, and the brazing of each contact surface does not affect each other, overcomes the existing adhesive of prior art, for the adhesive of multiple contact surfaces, there are often adhesive overflow, adhesion is not uniform and other problems, resulting in adhesive effect greatly discount.

Description

Technical Field

[0001] This invention relates to the field of wafer chucks, and more specifically, to a wafer chuck manufacturing process with excellent sealing performance. Background Technology

[0002] In semiconductor manufacturing, circuit elements are often formed on wafers. To determine the relative positions of these circuit elements to the wafer, notches are provided in the wafer's sidewalls. During wafer processing or inspection, it is frequently necessary to fix the wafer onto the processing equipment to facilitate processing. Currently, there are three main methods for fixing wafers in semiconductor processing: first, using a clamping head to hold the wafer; second, fixing the wafer onto the processing equipment through electrostatic adsorption; and third, using vacuum adsorption. Among these, vacuum adsorption ensures uniform force on the wafer, reduces the risk of damage, and has lower environmental requirements. Therefore, vacuum adsorption is the most widely used method for fixing wafers.

[0003] An existing wafer carrier chuck (application number CN202220379736.4) is composed of a polymer material plate and a substrate bonded together. The flatness and parallelism of the upper and lower contact surfaces of the polymer material plate and the substrate are both not less than 0.01. At least one spacer block assembly and at least one clamping block assembly are distributed on the outer edge of the wafer carrier chuck. A slotted positioning block and a rolling bearing are also provided on the outer edge of the wafer carrier chuck. At least one bushing is provided in the middle of the wafer carrier chuck. A cross-shaped air channel is formed in the middle of the polymer material plate. This technology utilizes vacuum adsorption to carry the wafer. To better ensure a tighter bond between the polymer material plate and the substrate, facilitating vacuum adsorption and improving its application in wafer inspection, the polymer material plate and the substrate are glued together, making the wafer carrier chuck more stable during vacuum adsorption. However, the glue still results in a loose bond between the polymer material plate and the substrate, leading to insufficient stability of the wafer carrier chuck. Summary of the Invention

[0004] The purpose of this invention is to provide a wafer chuck manufacturing process with excellent sealing performance, thereby solving the problem of uneven cooling in the prior art.

[0005] To achieve the above objectives, the embodiments of this application provide the following technical solutions:

[0006] A wafer chuck manufacturing process with excellent sealing properties includes the following steps:

[0007] S1. Prepare the panel;

[0008] S2. Install solder on the panel; the solder includes Si, Fe, Cu,

[0009] Mn, Mg, Zn, Al;

[0010] S3. Install the base plate;

[0011] S4. Perform vacuum brazing;

[0012] S5. Brazing heat treatment to obtain a wafer chuck.

[0013] This invention applies vacuum brazing technology to the manufacturing of wafer chucks. Vacuum brazing results in cleaner and stronger adhesion between the faceplate and baseplate. Compared to existing technologies using adhesives, this invention provides greater stability when the wafer chuck picks up the wafer under vacuum. Furthermore, this invention utilizes brazing heat treatment technology to avoid two common problems during vacuum brazing of aluminum alloys: First, as brazing progresses, the strengthening phases within the alloy develop attraction, gradually agglomerating and increasing their length, leading to a smaller contact area with grain boundaries and ultimately weakening the strengthening ability. Second, the brazing process continuously interferes with the Al matrix, causing Mg and Cu to be gradually drawn out and precipitated on the existing Mg2Si and CuAl2, thus reducing solid solution strengthening capabilities.

[0014] Furthermore, in step S1, the panel is CNC machined to obtain a panel with alternating grooves and surfaces on one side, and several annular through holes are also machined on the panel. The panel, used for placing the wafer, has two sides. The side that directly contacts the wafer uses several annular through holes to hold the wafer in place, while the other side is CNC machined to obtain a panel with alternating grooves (i.e., negative pressure grooves) and surfaces. In this invention, CNC machining produces a precise and flat panel. The annular negative pressure grooves and annular through holes facilitate wafer adsorption during negative pressure extraction by connecting the negative pressure grooves and annular through holes.

[0015] Furthermore, in step S2, different ratios of lead solder are selected based on different brazing temperatures. The choice of brazing temperature and lead solder ratio determines the success of the brazing process. Only brazing at a specific temperature with the corresponding lead solder ratio ensures a strong bond between the panel and the base plate without affecting vacuuming. Excessively high brazing temperatures increase the fluidity and wettability of the lead solder during manufacturing, causing it to flow into several negative pressure tanks, blocking vacuum channels and affecting subsequent vacuum wafer adsorption. Conversely, excessively low brazing temperatures result in a narrow crystal contact surface or insufficient melting, leading to unstable brazing adhesion and affecting the stability of subsequent wafer adsorption.

[0016] In the above scheme, the specific brazing temperatures and their corresponding lead solder ratios are as follows: When the brazing temperature is between 591℃ and 605℃, the solder, by mass percentage, comprises 9-10.5% Si, 0.8% Fe, 0.25% Cu, 0.1% Mn, 1-2% Mg, 0.2% Zn, and the balance Al; or the solder comprises 9-10.5% Si, 0.8% Fe, 0.25% Cu, 0.1% Mn, 1-2% Mg, 0.2% Zn, 0.1% Bi, and the balance Al; when the brazing temperature is between 585℃ and 605℃, the solder, by mass percentage, comprises 9.5-11% S. The brazing filler metal, by mass percentage, comprises 11-13% Si, 0.8% Fe, 0.25% Cu, 0.1% Mn, 0.2-1% Mg, 0.2% Zn, and the balance Al. When the brazing temperature is between 582℃ and 605℃, the brazing filler metal also comprises 11-13% Si, 0.8% Fe, 0.25% Cu, 0.1% Mn, 0.1% Mg, 0.2% Zn, and the balance Al. When the brazing temperature is between 580℃ and 600℃, the brazing filler metal also comprises 11-13% Si, 0.8% Fe, 0.25% Cu, 0.1% Mn, 1-2% Mg, 0.2% Zn, and the balance Al. Different brazing filler metal ratios and raw material selections, combined with specific brazing temperatures, are necessary to achieve a tighter and more stable bond between the front and back plates in a wafer chuck.

[0017] Furthermore, in S3, the base plate is first CNC machined, and then the base plate is attached to the panel with the panel on top. The side with lead solder is attached to the base plate, and the lead solder is below the panel. This ensures that the lead solder will not enter the negative pressure tank due to gravity during the brazing process, so as not to affect the subsequent vacuuming.

[0018] In this invention, the panel and the base plate have multiple contact surfaces (several annular surfaces), which are separated by annular negative pressure grooves. Solder is installed on these multiple contact surfaces (annular surfaces) between the panel and the base plate. The annular negative pressure grooves are divided into several groups, which are not interconnected. During vacuuming, vacuum channels of different depths can be set according to the wafer size. Vacuum channels of different depths connect to different groups of annular negative pressure grooves, enabling the adsorption of wafers of different sizes. Furthermore, applying vacuum brazing technology to the bonding of multiple contact surfaces between the panel and the base plate offers advantages over adhesive bonding. Vacuum brazing can achieve simultaneous brazing, and the brazing of each contact surface does not affect the others. Existing adhesive bonding technologies, when used for bonding multiple contact surfaces, often suffer from problems such as adhesive overflow and inconsistent adhesion, resulting in a significantly reduced bonding effect.

[0019] Specifically, in S4, the vacuum brazing process steps include:

[0020] S41. Select lead solder with different proportions according to different brazing temperatures;

[0021] S42. Place the assembled panel, solder, and base plate into a vacuum environment;

[0022] S43. Perform heat treatment, with a heating rate ≥12℃ / min and a vacuum degree <3×10⁻⁶. -3 Pa, working pressure ≤1×10 -3 Pa, pressure rise rate < 0.3 Pa / h; when the temperature is raised to 450℃, hold for 30 min, and when the temperature is raised to 500℃, hold for 5 min, with temperature control ±1℃.

[0023] Specifically, in S5, the brazing heat treatment has a heating rate ≥12℃ / min and a vacuum degree <3×10 -3 Pa, working pressure ≤1×10 -3 Pa, pressure rise rate < 0.3 Pa / h; when the temperature drops to 520℃, keep it at that temperature for 150 min, and when the temperature drops to 175℃, keep it at that temperature for 480 min, with temperature control ±1℃.

[0024] Furthermore, the wafer chuck obtained in S5 is mirror-polished and electroplated.

[0025] The beneficial effects of this invention are as follows:

[0026] 1. This invention applies vacuum brazing technology to wafer chucks. Compared with existing adhesive technology, this invention utilizes a specific ratio of lead solder and brazing temperature to make the wafer chuck more stable in adsorbing wafers, which is beneficial for subsequent wafer inspection.

[0027] 2. The manufacturing process of this invention also includes a brazing heat treatment step, which enhances the adhesion of aluminum alloys during vacuum brazing.

[0028] 3. The vacuum brazing technology in this invention can achieve simultaneous brazing of each contact surface without affecting each other, overcoming the problems of adhesive bonding in existing technologies, such as adhesive overflow and inconsistent bonding, which often result in a significant reduction in the bonding effect when bonding multiple contact surfaces. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the wafer chuck panel structure in this embodiment;

[0031] Figure 2 This is a schematic diagram of the wafer chuck base plate structure in this embodiment. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0033] It should be noted that similar labels or letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0034] like Figure 1 , 2 As shown, the wafer chuck of this invention includes a front panel 1 and a base plate 2. One side of the front panel 1 is used to place the wafer, and the other side is configured with a groove / surface, including several annular negative pressure grooves 11 and annular surfaces 12. The annular surfaces 12 are fitted to the base plate 2. The annular negative pressure grooves 11 and the front panel 1 form alternating grooves / surfaces. The annular negative pressure grooves 11 are vacuum passageways, and several through holes 13 are provided in the grooves. The wafer is attracted to the front panel 1 by the negative pressure adsorption capacity. When using this invention, the side of the front panel 1 with the groove / surface is facing down, the lead solder is installed on the annular surface 12, and the side with the wafer is facing up.

[0035] Panel 1 and base plate 2 are bonded together by brazing.

[0036] Example 1

[0037] A wafer chuck manufacturing process with excellent sealing properties includes the following steps:

[0038] S1. The panel described above is manufactured using CNC machining;

[0039] S2. Apply solder to the panel; the solder comprises, by weight percentage, 9-10.5% Si, 0.8% Fe, 0.25% Cu, 0.1% Mn, 1-2% Mg, 0.2% Zn, and the balance Al;

[0040] S3. The base plate is machined using CNC machining;

[0041] S4. Place the assembled panel, brazing filler metal, and base plate into a vacuum environment; select brazing temperatures of 591℃ (low temperature) and 605℃ (high temperature); then perform heat treatment with a heating rate ≥12℃ / min and a vacuum degree <3×10⁻⁶. -3 Pa, working pressure ≤1×10 - 3 Pa, pressure rise rate < 0.3 Pa / h; when the temperature is raised to 450℃, hold for 30 min, and when the temperature is raised to 500℃, hold for 5 min, with temperature control ±1℃.

[0042] S5. Brazing heat treatment to obtain a wafer chuck; i.e., heating rate ≥ 12℃ / min, vacuum degree < 3×10 -3 Pa, working pressure ≤1×10 -3 Pa, pressure rise rate < 0.3 Pa / h; when the temperature drops to 520℃, keep it at that temperature for 150 min, and when the temperature drops to 175℃, keep it at that temperature for 480 min, with temperature control ±1℃.

[0043] S6. Perform mirror polishing and electroplating on the wafer chuck obtained in S5.

[0044] Example 2

[0045] A wafer chuck manufacturing process with excellent sealing properties includes the following steps:

[0046] S1. The panel described above is manufactured using CNC machining;

[0047] S2. Apply solder to the panel; the solder comprises, by weight percentage, 9-10.5% Si, 0.8% Fe, 0.25% Cu, 0.1% Mn, 1-2% Mg, 0.2% Zn, 0.1% Bi, and the balance Al;

[0048] S3. The base plate is machined using CNC machining;

[0049] S4. Place the assembled panel, brazing filler metal, and base plate into a vacuum environment; select brazing temperatures of 591℃ (low temperature) and 605℃ (high temperature); then perform heat treatment with a heating rate ≥12℃ / min and a vacuum degree <3×10⁻⁶. -3 Pa, working pressure ≤1×10 - 3 Pa, pressure rise rate < 0.3 Pa / h; when the temperature is raised to 450℃, hold for 30 min, and when the temperature is raised to 500℃, hold for 5 min, with temperature control ±1℃.

[0050] S5. Brazing heat treatment to obtain a wafer chuck; i.e., heating rate ≥ 12℃ / min, vacuum degree < 3×10 -3 Pa, working pressure ≤1×10 -3 Pa, pressure rise rate < 0.3 Pa / h; when the temperature drops to 520℃, keep it at that temperature for 150 min, and when the temperature drops to 175℃, keep it at that temperature for 480 min, with temperature control ±1℃.

[0051] S6. Perform mirror polishing and electroplating on the wafer chuck obtained in S5.

[0052] Example 3

[0053] A wafer chuck manufacturing process with excellent sealing properties includes the following steps:

[0054] S1. The panel described above is manufactured using CNC machining;

[0055] S2. Apply solder to the panel; the solder comprises, by weight percentage, 9.5-11% Si, 0.8% Fe, 0.25% Cu, 0.1% Mn, 0.2-1% Mg, 0.2% Zn, and the balance Al;

[0056] S3. The base plate is machined using CNC machining;

[0057] S4. Place the assembled panel, brazing filler metal, and base plate into a vacuum environment; select brazing temperatures of 585℃ (low temperature) and 605℃ (high temperature); then perform heat treatment with a heating rate ≥12℃ / min and a vacuum degree <3×10⁻⁶. -3 Pa, working pressure ≤1×10 - 3 Pa, pressure rise rate < 0.3 Pa / h; when the temperature is raised to 450℃, hold for 30 min, and when the temperature is raised to 500℃, hold for 5 min, with temperature control ±1℃.

[0058] S5. Brazing heat treatment to obtain a wafer chuck; i.e., heating rate ≥ 12℃ / min, vacuum degree < 3×10 -3 Pa, working pressure ≤1×10 -3 Pa, pressure rise rate < 0.3 Pa / h; when the temperature drops to 520℃, keep it at that temperature for 150 min, and when the temperature drops to 175℃, keep it at that temperature for 480 min, with temperature control ±1℃.

[0059] S6. Perform mirror polishing and electroplating on the wafer chuck obtained in S5.

[0060] Example 4

[0061] A wafer chuck manufacturing process with excellent sealing properties includes the following steps:

[0062] S1. The panel described above is manufactured using CNC machining;

[0063] S2. Apply solder to the panel; the solder comprises, by weight percentage, 11-13% Si, 0.8% Fe, 0.25% Cu, 0.1% Mn, 0.1% Mg, 0.2% Zn, and the balance Al;

[0064] S3. The base plate is machined using CNC machining;

[0065] S4. Place the assembled panel, brazing filler metal, and base plate into a vacuum environment; select brazing temperatures of 582℃ (low temperature) and 605℃ (high temperature); then perform heat treatment with a heating rate ≥12℃ / min and a vacuum degree <3×10⁻⁶. -3 Pa, working pressure ≤1×10 - 3 Pa, pressure rise rate < 0.3 Pa / h; when the temperature is raised to 450℃, hold for 30 min, and when the temperature is raised to 500℃, hold for 5 min, with temperature control ±1℃.

[0066] S5. Brazing heat treatment to obtain a wafer chuck; i.e., heating rate ≥ 12℃ / min, vacuum degree < 3×10 -3 Pa, working pressure ≤1×10 -3 Pa, pressure rise rate < 0.3 Pa / h; when the temperature drops to 520℃, keep it at that temperature for 150 min, and when the temperature drops to 175℃, keep it at that temperature for 480 min, with temperature control ±1℃.

[0067] S6. Perform mirror polishing and electroplating on the wafer chuck obtained in S5.

[0068] Example 5

[0069] A wafer chuck manufacturing process with excellent sealing properties includes the following steps:

[0070] S1. The panel described above is manufactured using CNC machining;

[0071] S2. Apply solder to the panel; the solder comprises, by weight percentage, 11-13% Si, 0.8% Fe, 0.25% Cu, 0.1% Mn, 1-2% Mg, 0.2% Zn, and the balance Al;

[0072] S3. The base plate is machined using CNC machining;

[0073] S4. Place the assembled panel, brazing filler metal, and base plate into a vacuum environment; select a brazing temperature of 580℃ (low temperature) and 600℃ (high temperature); then perform heat treatment with a heating rate ≥12℃ / min and a vacuum degree <3×10⁻⁶. -3Pa, working pressure ≤1×10 - 3 Pa, pressure rise rate < 0.3 Pa / h; when the temperature is raised to 450℃, hold for 30 min, and when the temperature is raised to 500℃, hold for 5 min, with temperature control ±1℃.

[0074] S5. Brazing heat treatment to obtain a wafer chuck; i.e., heating rate ≥ 12℃ / min, vacuum degree < 3×10 -3 Pa, working pressure ≤1×10 -3 Pa, pressure rise rate < 0.3 Pa / h; when the temperature drops to 520℃, keep it at that temperature for 150 min, and when the temperature drops to 175℃, keep it at that temperature for 480 min, with temperature control ±1℃.

[0075] S6. Perform mirror polishing and electroplating on the wafer chuck obtained in S5.

[0076] Negative pressure tests were conducted using the wafer chucks described in Examples 1-5, and the results are shown in Table 1 below.

[0077]

[0078]

[0079] From Table 1, we can conclude that the wafer chuck prepared by this invention has good sealing performance, which greatly improves the wafer adsorption capacity and facilitates subsequent wafer testing.

[0080] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A wafer chuck manufacturing process, comprising the following steps: S1. Prepare the panel; S2. Install solder on the panel; the solder comprises Si, Fe, Cu, Mn, Mg, Zn, and Al, and at brazing temperatures of 591°C (low temperature) and 605°C (high temperature), the solder comprises, by mass percentage, 9-10.5% Si, 0.8% Fe, 0.25% Cu, 0.1% Mn, 1-2% Mg, 0.2% Zn, and the balance Al; or the solder comprises 9-10.5% Si, 0.8% Fe, 0.25% Cu, 0.1% Mn, 1-2% Mg, 0.2% Zn, 0.1% Bi, and the balance Al; at brazing temperatures of 585°C (low temperature) and 605°C (high temperature), the solder comprises, by mass percentage, Si, Fe, Cu, Mn, Mg, Zn, and Al. The brazing filler metal comprises, by mass percentage, 9.5-11% Si, 0.8% Fe, 0.25% Cu, 0.1% Mn, 0.2-1% Mg, 0.2% Zn, and the balance Al; at brazing temperatures of 582℃ (low temperature) and 605℃ (high temperature), the brazing filler metal comprises, by mass percentage, 11-13% Si, 0.8% Fe, 0.25% Cu, 0.1% Mn, 0.1% Mg, 0.2% Zn, and the balance Al; at brazing temperatures of 580℃ (low temperature) and 600℃ (high temperature), the brazing filler metal comprises, by mass percentage, 11-13% Si, 0.8% Fe, 0.25% Cu, 0.1% Mn, 1-2% Mg, 0.2% Zn, and the balance Al. S3. Install the base plate; S4. Perform vacuum brazing; S5. Brazing heat treatment to obtain a wafer chuck.

2. The wafer chuck manufacturing process according to claim 1, characterized in that, The wafer chuck includes a front panel and a back panel. The front panel has several annular through holes. One side of the front panel is used to place the wafer, and the other side is configured with alternating grooves and surfaces.

3. The wafer chuck manufacturing process according to claim 2, characterized in that, In S1, the panel with alternating grooves and surfaces is placed with one side facing down.

4. The wafer chuck manufacturing process according to claim 2, characterized in that, In step S2, brazing materials with different ratios are selected according to different brazing temperatures, and the brazing materials are installed on the alternating surfaces of the panel.

5. A wafer chuck manufacturing process according to claim 2, characterized in that, In step S3, the base plate is first CNC machined, and then it is attached to the side of the panel with solder installed, with the panel on top and the base plate on the bottom.

6. The wafer chuck manufacturing process according to claim 2, characterized in that, In S4, the vacuum brazing process steps include: S41. Select brazing filler metals with different proportions according to different brazing temperatures; S42. Place the assembled panel, solder, and base plate into a vacuum environment; S43. Perform heat treatment, with a heating rate ≥12℃ / min and a vacuum degree <3×10⁻⁶. -3 Pa and working pressure ≤ 1×10 -3 Pa, pressure rise rate < 0.3 Pa / h; when the temperature is raised to 450℃, hold for 30 min, and when the temperature is raised to 500℃, hold for 5 min, with temperature control ±1℃.

7. A wafer chuck manufacturing process according to claim 2, characterized in that, In step S5, the brazing heat treatment has a heating rate ≥12℃ / min and a vacuum degree <3×10⁻⁶. -3 Pa, working pressure ≤1×10 -3 Pa, pressure rise rate < 0.3 Pa / h; when the temperature drops to 520℃, keep it at that temperature for 150 min, and when the temperature drops to 175℃, keep it at that temperature for 480 min, with temperature control ±1℃.

8. A wafer chuck manufacturing process according to claim 2, characterized in that, The wafer chuck obtained in S5 is mirror polished and electroplated.

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