Electrostatic chuck with double-sided adsorption and assembly structure thereof

Abstract

The application provides a double-sided adsorption electrostatic chuck and an assembling structure thereof. The double-sided adsorption electrostatic chuck comprises a base, an electrode layer attached to the surface of the base, and a dielectric layer located on the side of the electrode layer away from the base. The electrode layer comprises an upper electrode plated on the upper surface of the base and a lower electrode plated on the lower surface of the base. The dielectric layer comprises an upper dielectric layer arranged on the side of the upper electrode away from the base and a lower dielectric layer arranged on the side of the lower electrode away from the base. The product to be adsorbed is adsorbed on the electrostatic chuck through the upper electrode, and the electrostatic chuck is adsorbed on the base through the lower electrode. The connection between the electrostatic chuck and the base can be strengthened through the pin hole. The double-sided adsorption electrostatic chuck and the assembling structure thereof can reduce the influence of local strain on the product and are suitable for various application environments.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing processes, and more specifically, to a double-sided electrostatic chuck and its assembly structure with a base. Background Technology

[0002] Currently, electrostatic chucks are commonly used in semiconductor manufacturing processes to hold and transport objects such as wafers, masks, and glass. Their main principle is to apply a voltage between two insulating plates, creating an electrostatic field. When an object approaches the plates, electrostatic induction induces a charge on its surface opposite to the electrode surface, causing it to be attracted by the chuck. Compared to mechanical clamping, bonding, and vacuum chucks, electrostatic chucks offer advantages such as uniform adsorption force, less damage and contamination to the wafer, and suitability for vacuum environments. Electrostatic chucks are classified into two types based on their adsorption force formation mechanism: Coulomb type and Johnsen-Rahbek type. Coulomb type chucks have a smaller adsorption force but are less sensitive to minor defects and can operate at room temperature, making them easier to implement. Johnsen-Rahbek type chucks, while having a larger adsorption force, require heating and have higher overall design requirements. Both types of chucks are widely used in the semiconductor industry.

[0003] There are several existing methods for fixing electrostatic chucks to their bases, mainly including mechanical connections (such as fastener connections or mechanical clamping), vacuum adsorption, and bonding. Each method has its advantages and disadvantages. Mechanical connections can cause localized stress and strain on the chuck itself; vacuum adsorption requires a vacuum chuck or a similar structure, which is not suitable for working in a vacuum environment; and bonding results in poor maintainability. Summary of the Invention

[0004] In view of the above problems, the purpose of this invention is to provide a double-sided electrostatic chuck and its assembly structure to solve the problems of existing electrostatic chucks, such as the inability to guarantee adsorption quality, limited application range, and impact on the accuracy of adsorption of products.

[0005] The electrostatic chuck with double-sided adsorption provided by the present invention includes a substrate, an electrode layer attached to the surface of the substrate, and a dielectric layer located on the side of the electrode layer away from the substrate; wherein, the electrode layer includes an upper electrode plated on the upper surface of the substrate and a lower electrode plated on the lower surface of the substrate; the dielectric layer includes an upper dielectric layer disposed on the side of the upper electrode away from the substrate and a lower dielectric layer disposed on the side of the lower electrode away from the substrate; the product to be adsorbed is limited on the upper dielectric layer, the product to be adsorbed is adsorbed on the upper dielectric layer through the upper electrode, and the lower dielectric layer is adsorbed on the external base through the lower electrode.

[0006] Furthermore, a preferred technical solution is that the upper electrode is a nested bipolar concentric ring electrode with equal area; and the structure of the lower electrode is the same as that of the upper electrode.

[0007] Furthermore, a preferred technical solution is that uniformly distributed bumps are provided on the upper surface of the upper dielectric layer, and continuously distributed bosses surrounding the bumps are provided at the edge of the upper dielectric layer; the product to be adsorbed comes into contact with the bosses and bumps.

[0008] Furthermore, a preferred technical solution is that the upper dielectric layer and the boss are integrally formed.

[0009] In addition, a preferred technical solution is that the substrate includes an upper substrate and a lower substrate that are adapted and connected; a gas-liquid cooling structure is provided at the junction of the upper substrate and the lower substrate, and the gas-liquid cooling structure is used to cool the product to be adsorbed.

[0010] Furthermore, a preferred technical solution is that the gas-liquid cooling structure is a regularly distributed annular or arc-shaped structure.

[0011] In addition, a preferred technical solution is that the inlet and outlet of the gas-liquid cooling structure are symmetrically distributed on the extension platform of the substrate, or the outlet of the gas-liquid cooling structure is evenly distributed on the channel of the gas-liquid cooling structure.

[0012] Furthermore, a preferred technical solution is to provide at least two temperature sensors evenly distributed around the perimeter of the substrate; the temperature sensors include a PTC temperature sensor with a positive temperature coefficient and an NTC temperature sensor with a negative temperature coefficient.

[0013] In addition, a preferred technical solution is to provide two symmetrically distributed positioning blocks on the substrate; an electrode connector is provided in each positioning block, the electrode connector including an insulating component, an electrode sheet, an electrode post and a positioning pin hole, and the electrode post is connected to the corresponding electrode of the electrode layer.

[0014] According to another aspect of the present invention, an electrostatic chuck assembly structure is provided, including a micro-motion stage, a reflector block disposed on the micro-motion stage, and a double-sided electrostatic chuck disposed on the reflector block, wherein the double-sided electrostatic chuck is as described above; wherein the product to be adsorbed is fixed to the double-sided electrostatic chuck by the adsorption force of the upper surface of the double-sided electrostatic chuck, and the double-sided electrostatic chuck is fixed to the reflector block by the adsorption force of the lower surface.

[0015] By utilizing the aforementioned double-sided electrostatic chuck and its assembly structure, local strain of the electrostatic chuck can be reduced, preventing surface distortion of the adsorbed object due to deformation of the chuck itself. Furthermore, this structure has a wide range of applications, suitable for use in both vacuum and atmospheric environments.

[0016] To achieve the foregoing and related objectives, one or more aspects of the invention include the features that will be described in detail below. The following description and accompanying drawings illustrate certain exemplary aspects of the invention. However, these aspects indicate only a few of the various ways in which the principles of the invention can be used. Furthermore, the invention is intended to encompass all such aspects and their equivalents. Attached Figure Description

[0017] Other objects and results of the invention will become more apparent and readily understood with reference to the following description taken in conjunction with the accompanying drawings. In the drawings:

[0018] Figure 1 A top view of a double-sided electrostatic chuck according to an embodiment of the present invention;

[0019] Figure 2 A cross-sectional view of a double-sided electrostatic chuck according to an embodiment of the present invention;

[0020] Figure 3 This is a schematic diagram of the electrode layer structure of the electrostatic chuck with double-sided adsorption according to an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram showing the distribution of cooling water channels and gas channels of a double-sided adsorption electrostatic chuck according to an embodiment of the present invention.

[0022] Figure 5 This is a top view of the assembly structure of the double-sided electrostatic chuck and base according to an embodiment of the present invention;

[0023] Figure 6 This is a partial cross-sectional view of the assembly structure of the double-sided electrostatic chuck and base according to an embodiment of the present invention.

[0024] The reference numerals in the figures include: assembly structure 100, double-sided electrostatic chuck 101, micro-motion stage 102, reflector block 103, positioning structure 104, upper substrate 1, upper electrode 2, upper dielectric layer 3, bump 4, boss 5, gas channel outlet 6, gas channel 7, cooling water channel 8, lower substrate 9, lower electrode 10, lower dielectric layer 11, positioning block 12, temperature sensor 13, push rod through hole 14, electrode 2a, electrode 2b.

[0025] In all the accompanying drawings, the same reference numerals indicate similar or corresponding features or functions. Detailed Implementation

[0026] In the following description, numerous specific details are set forth for illustrative purposes and to provide a thorough understanding of one or more embodiments. However, it will be apparent that these embodiments may also be implemented without these specific details. In other instances, well-known structures and devices are shown in block diagram form for ease of description of one or more embodiments.

[0027] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to 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 this invention.

[0028] To describe in detail the double-sided electrostatic chuck and its assembly structure of the present invention, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0029] Figure 1 and Figure 2 The schematic structure of the electrostatic chuck with double-sided adsorption according to an embodiment of the present invention is shown from different angles.

[0030] like Figure 1 and Figure 2 As shown in the figure, the double-sided electrostatic chuck 101 (hereinafter referred to as electrostatic chuck) of this invention includes a substrate, an electrode layer attached to the surface of the substrate, and a dielectric layer located on the side of the electrode layer away from the substrate. The electrode layer includes an upper electrode 2 plated on the upper surface of the substrate and a lower electrode 10 plated on the lower surface of the substrate. The dielectric layer includes an upper dielectric layer 3 disposed on the side of the upper electrode 2 away from the substrate and a lower dielectric layer 11 disposed on the side of the lower electrode 10 away from the substrate. The product to be adsorbed is positioned on the upper dielectric layer 3, and the product to be adsorbed is adsorbed on the upper dielectric layer 3 through the upper electrode 2. The lower dielectric layer 11 is adsorbed on the external base through the lower electrode 10.

[0031] To demonstrate the internal structure of the double-sided electrostatic chuck, Figure 3 and Figure 4 These are schematic cross-sectional views of a double-sided electrostatic chuck along the center of the electrode layer and the substrate, respectively.

[0032] Combination Figures 1 to 4As shown in the figure, the double-sided electrostatic chuck 101 of this invention has an upper electrode 2 that is a nested bipolar concentric ring electrode with equal area. It may include at least two arc-shaped or circular bipolar electrodes that are spaced apart and concentrically distributed. The bipolar electrodes of the upper electrode 2 include electrode 2a and electrode 2b, which are two concentric conducting rings nested together in the same plane. The electrodes can be made of conductive materials such as chromium, aluminum, or copper, and are plated onto the substrate surface using a special process. The thickness of the upper electrode 2 can be set to 0.01 mm, and the areas of electrode 2a and electrode 2b are set to be approximately equal, each 26630 mm². 2 By setting the upper electrode 2 to a bipolar electrode cross distribution, the uniformity of the electrostatic chuck's adsorption force can be ensured, effectively guaranteeing the clamping accuracy requirements and the surface accuracy of the adsorbed object.

[0033] It should be noted that the lower electrode 10 is also configured as a nested bipolar concentric ring electrode with equal area. The bipolar electrode structure of the lower electrode 10 can be configured to be the same as that of the upper electrode 2, or it can be configured to be other forms of electrode distribution. This invention does not impose specific limitations on this.

[0034] In the double-sided electrostatic chuck of the present invention, uniformly distributed bumps 4 are provided on the upper surface of the upper dielectric layer 3, and continuously distributed bosses 5 surrounding the bumps 4 are provided at the edge of the upper dielectric layer 3. The product to be adsorbed comes into contact with the bosses 5 and bumps 4. The function is to reduce the flatness requirement of the upper surface, thereby reducing the processing difficulty, and to form a gas gap between the adsorbed object and the dielectric layer to conduct away the heat generated on the adsorbed object due to etching and other processes. The lower dielectric layer 11 can adopt the same or similar structural form as the upper dielectric layer 3. Here, only the upper dielectric layer 3 is used as an example for structural description.

[0035] The upper surface of the upper dielectric layer 3 is provided with a plurality of uniformly distributed bumps 4. The bumps 4 can be configured as cylindrical structures. In a specific embodiment of the present invention, the cross-sectional diameter of the bumps 4 is set to 0.5 mm, and the distance between two adjacent bumps 4 is 6 mm. Circular bosses 5 are provided on the edge of the upper dielectric layer 3. The bosses 5 are continuously distributed on the circumferential edge of the upper dielectric layer 3. When the upper dielectric layer 3 and the bosses 5 come into contact with the product to be adsorbed, a portion of the gas can be sealed. The height of the bosses 5 is set to be the same as the height of the bumps 4.

[0036] To simplify the manufacturing process of the upper dielectric layer 3, the upper dielectric layer 3 and the boss 5 can be integrally molded. The bump 4 is processed onto the upper dielectric layer 3 in a second process. Furthermore, the upper dielectric layer 3, the bump 4, and the boss 5 can be made of the same ceramic material and manufactured in one step, or they can be completed in two separate processes. It should also be noted that the lower dielectric layer 11 can adopt the same structural form as the upper dielectric layer 3, that is, corresponding bosses and bumps can be provided on the lower dielectric layer 11.

[0037] In the double-sided electrostatic chuck of the present invention, three push rod through holes 14 are provided inside the upper dielectric layer 3 and the lower dielectric layer 11. During the process of picking up and placing the product to be picked up, the push rod can be pushed out through the corresponding push rod through hole 14 and lift the product to be picked up to a certain height, forming a sufficient gap between the product to be picked up and the dielectric layer. Then, the robot arm that picks up and places the product to be picked up is inserted, and the push rod is controlled to retract. The product to be picked up falls onto the robot arm, and the robot arm completes the picking up and placing of the product to be picked up.

[0038] To facilitate substrate processing, the substrate is configured into two parts: an upper substrate 1 and a lower substrate 9 that are adapted and connected, which together form a complete substrate structure. In addition, a gas-liquid cooling structure is provided at the junction of the upper substrate 1 and the lower substrate 9. The gas-liquid cooling structure is used to cool the product to be adsorbed and the electrostatic chuck. Specifically, the gas-liquid cooling structure may include a cooling water channel 8 and a gas channel 7. The cooling water channel 8 is used to cool the electrostatic chuck, reduce the temperature gradient between different zones, and avoid deformation caused by temperature changes and uneven temperatures, which would affect the accuracy. The gas channel 7 is used to cool the product to be adsorbed, prevent the temperature from rising and generating a thermal effect on surrounding objects, and expand the applicability of the electrostatic chuck.

[0039] Specifically, the substrate can be circular, and the substrate material can be various materials such as metal, ceramic, and glass. The cooling water channel 8 and the gas channel 7 can be set as a regularly distributed annular or arc-shaped structure. Various types of gases such as helium, nitrogen, neon, and argon can be filled into the gas channel 7. Through the interaction of the gas and the cooling water channel 8, the temperature of the electrostatic chuck and the product to be adsorbed can be adjusted to ensure the adsorption accuracy of the product.

[0040] As a specific example, the inlet and outlet of the gas-liquid cooling structure can be symmetrically distributed on the extension platform of the substrate, or the outlet of the gas-liquid cooling structure can be evenly distributed on the channel of the gas-liquid cooling structure. For example, the inlet and outlet of the cooling water channel 8 can be symmetrically distributed on the extension platform of the substrate. The extension platform is a platform-shaped structure with positioning blocks 12 and extending out from the substrate. The gas channel 7 includes two non-conductive semi-circular arc channels located at the edge of the substrate. The inlet of the gas channel can also be set on the extension platform. The outlet 6 of the gas channel passes through the upper substrate 1 and the upper dielectric layer 3 in sequence and is evenly distributed on the semi-circular arc channel. For example, the diameter of the outlet 6 of the gas channel can be set to 1 mm. The outlet 6 of the gas channel is set to be perpendicular to the substrate and leads to the contact surface between the upper dielectric layer 3 and the product to be adsorbed, thereby directly cooling the product to be adsorbed.

[0041] To ensure the temperature uniformity of the electrostatic chuck, several arc-shaped grooves are provided around the base (the specific structure of the six arc-shaped grooves is shown in the attached figure). Temperature sensors 13 are installed in each arc-shaped groove. The temperature sensors 13 are evenly distributed around the base and include PTC temperature sensors with positive temperature coefficients and NTC temperature sensors with negative temperature coefficients. The PTC temperature sensors can be used for temperature alarms. When the real-time temperature of the base exceeds a preset threshold, an alarm can be triggered. The NTC temperature sensors are used for temperature acquisition and to measure the temperature value at the corresponding location.

[0042] It should be noted that the PTC temperature sensor and NTC temperature sensor mentioned above can be set in the same arc-shaped groove at the same time, or they can be set in different arc-shaped grooves at intervals. The specific settings or adjustments can be made according to the structure and requirements of the product, so that the operator can accurately monitor the temperature of the entire electrostatic chuck.

[0043] In one specific embodiment of the present invention, two symmetrically distributed positioning blocks 12 are provided on the substrate; an electrode connector is provided in each positioning block 12, and each electrode connector includes an insulating component, two electrode plates, two electrode posts and a positioning pin hole. The two electrode posts are respectively connected to two electrodes of different polarities of the corresponding electrode layer; a positioning pin hole is provided on the positioning block 12. If the electrostatic adsorption force is insufficient to keep the electrostatic chuck in place, the electrostatic chuck can be fixed by the positioning pin.

[0044] Corresponding to the above-mentioned double-sided electrostatic chuck, the present invention also provides an assembly structure for a double-sided electrostatic chuck and a base, which applies the electrostatic chuck to the micro-stage of a lithography machine.

[0045] Specifically, Figure 5 and Figure 6 The following are schematic diagrams illustrating the assembly structure of the electrostatic chuck and the base according to embodiments of the present invention.

[0046] like Figure 5 and Figure 6 As shown in the figure, the electrostatic chuck assembly structure 100 of this embodiment includes a micro-motion stage 102, a reflector block 103 disposed on the micro-motion stage 102, and a double-sided electrostatic chuck 101 disposed on the reflector block 103; wherein, the product to be adsorbed is fixed to the double-sided electrostatic chuck 101 by the adsorption force of the upper surface of the double-sided electrostatic chuck 101, and fixed to the reflector block 103 by the adsorption force of the lower surface of the double-sided electrostatic chuck 101.

[0047] To prevent the double-sided electrostatic chuck 101 from sliding laterally on the reflector block 103 during acceleration, several mechanical positioning structures 104 can be set between the double-sided electrostatic chuck 101 and the reflector block 103 to horizontally position the electrostatic chuck and the reflector block 103. The mechanical positioning structure 104 can adopt various positioning forms such as fasteners and positioning pins.

[0048] It should be noted that the embodiments of the electrostatic chuck assembly structure can be referred to the description in the embodiments of the double-sided adsorption electrostatic chuck, and will not be repeated here.

[0049] The electrostatic chuck with double-sided adsorption and its assembly structure provided by the present invention adopts an electrode structure with nested bipolar concentric rings of equal area to ensure the uniformity of electrostatic adsorption force and avoid the impact of uneven force on the surface shape of the product to be adsorbed on accuracy. In addition, a gas-liquid cooling structure is provided, which can simultaneously cool the product to be adsorbed and the electrostatic chuck to avoid temperature differences caused by uneven local heating of the product to be adsorbed. It can be seen that the electrostatic chuck with double-sided adsorption of the present invention is applicable to coulomb-type chuck structures, which can not only control the working temperature of the chuck, but also ensure sufficient adsorption force, and can be widely used in the semiconductor industry.

[0050] The electrostatic chuck with double-sided adsorption and its assembly structure according to the present invention have been described above by way of example with reference to the accompanying drawings. However, those skilled in the art should understand that various modifications can be made to the electrostatic chuck with double-sided adsorption and its assembly structure according to the present invention without departing from the scope of the invention. Therefore, the scope of protection of the present invention should be determined by the contents of the appended claims.

Claims

1. A double-sided electrostatic chuck, characterized in that, include: A substrate, an electrode layer attached to the surface of the substrate, and a dielectric layer located on the side of the electrode layer away from the substrate; wherein, The electrode layer includes an upper electrode plated on the upper surface of the substrate and a lower electrode plated on the lower surface of the substrate; The dielectric layer includes an upper dielectric layer disposed on the side of the upper electrode away from the substrate and a lower dielectric layer disposed on the side of the lower electrode away from the substrate. The product to be adsorbed is adsorbed onto the upper dielectric layer via the upper electrode, and the lower dielectric layer is adsorbed onto the external base via the lower electrode; Several evenly distributed arc-shaped grooves are provided around the base, and a temperature sensor is provided in each arc-shaped groove. The temperature sensor includes a PTC temperature sensor with a positive temperature coefficient and an NTC temperature sensor with a negative temperature coefficient. The NTC temperature sensor is used for temperature acquisition, and the PTC temperature sensor is used to issue an alarm when the real-time temperature of the substrate exceeds a preset threshold. Two symmetrically distributed positioning blocks are provided on the substrate; Electrode connectors are respectively provided in the positioning block. Each electrode connector includes an insulating component, an electrode sheet, an electrode post, and a positioning pin hole. The electrode post is connected to the corresponding electrode of the electrode layer. When the electrostatic adsorption force is insufficient to ensure that the electrostatic chuck remains stationary, the electrostatic chuck is further fixed by means of a positioning pin and the positioning pin hole.

2. The electrostatic chuck with double-sided adsorption as described in claim 1, characterized in that, The upper electrode is a nested bipolar concentric ring electrode with equal area; and the structure of the lower electrode is the same as that of the upper electrode.

3. The electrostatic chuck with double-sided adsorption as described in claim 1, characterized in that, The upper surface of the upper dielectric layer is provided with uniformly distributed bumps, and the edge of the upper dielectric layer is provided with continuously distributed bosses surrounding the bumps. The product to be adsorbed comes into contact with the boss and the protrusion.

4. The electrostatic chuck with double-sided adsorption as described in claim 3, characterized in that, The upper dielectric layer and the boss are integrally formed.

5. The electrostatic chuck with double-sided adsorption as described in claim 3, characterized in that, The substrate includes an upper substrate and a lower substrate that are adapted and connected; A gas-liquid cooling structure is provided at the junction of the upper substrate and the lower substrate, and the gas-liquid cooling mechanism is used to cool the product to be adsorbed.

6. The electrostatic chuck with double-sided adsorption as described in claim 5, characterized in that, The gas-liquid cooling structure is a regularly distributed ring or arc shape.

7. The electrostatic chuck with double-sided adsorption as described in claim 5, characterized in that, The inlet and outlet of the gas-liquid cooling structure are symmetrically distributed on the extension platform of the substrate, or the outlet of the gas-liquid cooling structure is evenly distributed on the channel of the gas-liquid cooling structure.

8. An electrostatic chuck assembly structure, characterized in that, The device includes a micro-motion stage, a reflector block disposed on the micro-motion stage, and a double-sided electrostatic chuck disposed on the reflector block, wherein the double-sided electrostatic chuck is as described in any one of claims 1 to 7; wherein... The product to be adsorbed is fixed to the double-sided electrostatic chuck by the electrostatic adsorption force of the upper surface of the double-sided electrostatic chuck, and the double-sided electrostatic chuck is fixed to the reflector block by the adsorption force of the lower surface.

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