Electrostatic chucking type chuck

Abstract

This invention discloses an electrostatic adsorption chuck, belonging to the field of electrostatic bearing technology for semiconductor vacuum process equipment. It includes a ceramic substrate with an electrostatic adsorption electrode embedded within it. An insulating dielectric layer is deposited on the upper surface of the ceramic substrate. The electrostatic adsorption electrode is electrically connected to a high-voltage terminal. A metal mounting base is fixedly installed at the bottom of the ceramic substrate. This invention, through its ceramic substrate, electrostatic adsorption electrode, insulating dielectric layer, high-voltage terminal, and metal mounting base, eliminates thermal interference, achieves a uniform process environment at room temperature, and improves the yield of precision testing, room-temperature coating, and vacuum settling processes. It eliminates redundant circuitry, resulting in a more uniform adsorption electric field and higher positioning accuracy, making it suitable for ultra-high vacuum and high-purity nitrogen sealed environments. The overall structure is simple, yields high efficiency, is low-cost, easy to mass-produce, and has no idle electrical structures, thus extending the equipment's service life.

Description

Technical Field

[0001] This invention belongs to the field of electrostatic bearing technology for semiconductor vacuum process equipment, and specifically relates to an electrostatic adsorption chuck. Background Technology

[0002] Electrostatic chucks are clamps that use the principle of electrostatic adsorption to fix the adsorbed objects. Due to their advantages such as uniform adsorption force, low pollution, and ability to operate in a vacuum environment, they have become the most widely used wafer clamping tool in semiconductor manufacturing processes.

[0003] Traditional electrostatic chucks used in existing semiconductor equipment are mostly composite structures that integrate adsorption and heating, simultaneously integrating a high-voltage adsorption electrode layer, a heating resistor layer, temperature measurement circuitry, and temperature control compensation circuitry. These composite electrostatic chucks with heating are mainly designed for high-temperature etching and high-temperature deposition processes, and their structures are complex, typically multi-layered composite stacked structures with numerous and complex ceramic sintering layers.

[0004] However, the semiconductor industry chain includes numerous room-temperature processes that require only stable adsorption and fixation without heating, such as wafer inspection, visual inspection, room-temperature cleaning, room-temperature coating, slicing pretreatment, vacuum room-temperature testing, and nitrogen-environment static curing. Under these room-temperature process conditions, traditional heated electrostatic chucks have the following shortcomings:

[0005] (1) The internal integrated heating resistance wire and multi-layer composite stacked structure result in an excessively large overall thickness of the suction cup, concentrated internal sintering stress, poor flatness consistency of the cup surface, and the heating layer becomes completely useless and instead becomes the source of structural defects.

[0006] (2) The built-in heating PWM power circuit, temperature measurement signal line, and temperature control closed-loop module still exist even if the heating function is turned off. When vacuum high-pressure adsorption is working, electromagnetic noise is generated, which interferes with the uniformity of the high-pressure adsorption electric field and causes the wafer positioning accuracy to decrease.

[0007] (3) Even if heating is not turned on, the internal multilayer metal heating substrate and ceramic heat capacity are inconsistent. During the vacuum of the cavity and the flow of nitrogen gas, a natural temperature difference will be generated, resulting in a small temperature gradient on the wafer surface, which affects the accuracy of room temperature detection.

[0008] (4) Multiple interfaces and multiple circuits result in more sintering interfaces and more micropores, leading to a high probability of vacuum leakage.

[0009] (5) Retaining the entire heating power supply circuit, the idle circuit is prone to accumulating charge, generating weak leakage current and micro-arc hazards, and the equipment maintenance cost is high;

[0010] (6) The room temperature process does not require heating at all, but it is necessary to purchase a full-function high temperature suction cup, resulting in a significant waste of manufacturing costs. Summary of the Invention

[0011] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an electrostatic adsorption suction cup.

[0012] The technical solution adopted to solve the above technical problems is: an electrostatic adsorption suction cup, including a ceramic substrate, an electrostatic adsorption electrode embedded inside the ceramic substrate, an insulating dielectric layer laid on the upper surface of the ceramic substrate, the electrostatic adsorption electrode electrically connected to a high voltage terminal, and a metal mounting base fixedly installed at the bottom end of the ceramic substrate.

[0013] Furthermore, the ceramic matrix is ​​a few-layer sintered ceramic structure.

[0014] The above technical solution is suitable for ultra-high vacuum and high-purity nitrogen sealing environments, eliminating the problems of gas leakage and seepage.

[0015] Furthermore, the high-voltage terminal is equipped with only one set of adsorption electrode connections.

[0016] With the above technical solution, the circuit system retains only the high-voltage adsorption circuit, avoiding electromagnetic crosstalk in the heating circuit, and greatly improving the consistency of the high-voltage adsorption electric field distribution.

[0017] Furthermore, the ceramic matrix is ​​composed entirely of ceramic materials.

[0018] The above technical solution eliminates the need for an internal metal heating and heat storage layer, ensuring ultra-high precision in room temperature processes, optical inspection, and dimensional inspection.

[0019] Furthermore, the insulating dielectric layer covers the electrostatic adsorption electrode.

[0020] Through the above technical solution, the insulating dielectric layer has a uniform thickness, which is used to isolate the high voltage electric field and provide a stable adsorption interface, ensuring that the adsorption force is uniformly transmitted to the surface of the adsorbed workpiece.

[0021] The beneficial effects of this invention are as follows:

[0022] (1) By setting up a ceramic substrate, electrostatic adsorption electrode, insulating dielectric layer, high voltage terminal and metal mounting base, thermal interference is eliminated, a uniform process environment at room temperature is achieved, the plate surface has no heat storage, no heat release and no micro temperature difference, improving the yield of precision detection, room temperature coating and vacuum static process; redundant circuits are removed, making the adsorption electric field more uniform and the positioning accuracy higher, which is suitable for high-end precision alignment process. At the same time, the structure is dense and defect-free, the ultra-high vacuum sealing performance is excellent, the multi-layer sintering interface is reduced, and it is suitable for ultra-high vacuum and high-purity nitrogen sealing environment.

[0023] (2) The device has a simple overall structure, high yield, low cost, and is easy to mass-produce, which greatly reduces manufacturing and maintenance costs. It also has no idle electrical structure, eliminates the risk of leakage, arcing, and electric arc, and improves the service life of the equipment. It is suitable for semiconductor process scenarios that do not require heating, such as vacuum room temperature detection, nitrogen environment curing, room temperature cleaning, pre-processing slicing, and optical re-inspection. Attached Figure Description

[0024] Figure 1 This is a perspective view of an electrostatic adsorption suction cup according to the present invention;

[0025] Figure 2 This invention relates to the structure of an electrostatic adsorption suction cup. Figure 1 ;

[0026] Figure 3 This invention relates to the structure of an electrostatic adsorption suction cup. Figure 2 .

[0027] Reference numerals: 1. Ceramic substrate; 2. Electrostatic adsorption electrode; 3. Insulating dielectric layer; 4. High voltage terminal; 5. Metal mounting base. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0029] like Figures 1-3 As shown, an electrostatic adsorption suction cup of this embodiment includes a ceramic substrate 1, an electrostatic adsorption electrode 2 embedded inside the ceramic substrate 1, the electrostatic adsorption electrode 2 being a thin electrode made of conductive material, preferably a tungsten electrode or a molybdenum electrode, because its coefficient of thermal expansion is similar to that of alumina ceramic, which can avoid ceramic cracking due to thermal mismatch during sintering and use. An insulating dielectric layer 3 is laid on the upper surface of the ceramic substrate 1, the electrostatic adsorption electrode 2 is electrically connected to a high voltage terminal 4, and a metal mounting base 5 is fixedly installed at the bottom of the ceramic substrate 1.

[0030] The ceramic matrix 1 is a few-layer sintered ceramic structure, which greatly reduces the number of sintering interfaces. The ceramic has high overall density, no micropores or delamination defects, and is suitable for ultra-high vacuum and high-purity nitrogen sealing environments, eliminating leakage and seepage problems.

[0031] The high-voltage terminal 4 is equipped with only one set of adsorption electrode wiring. The whole machine has no heating PWM drive circuit and no temperature measurement sampling line. The circuit system only retains the high-voltage adsorption circuit, completely eliminating redundant electrical modules, avoiding electromagnetic crosstalk of the heating circuit, greatly improving the consistency of the high-voltage adsorption electric field distribution, and the workpiece adsorption is flat, without deviation, and without micro-shaking.

[0032] The ceramic substrate 1 is composed entirely of ceramic materials, which are made of alumina or aluminum nitride ceramic materials. There is no metal heating and heat storage layer inside. The ceramic substrate has uniform thermal properties. In a vacuum and nitrogen gas flow environment, there is no temperature difference, no thermal gradient, and no passive heat release, ensuring ultra-high precision for room temperature processes, optical inspection, and dimensional inspection.

[0033] An insulating dielectric layer 3 covers the electrostatic adsorption electrode 2. The insulating dielectric layer 3 has a uniform thickness and is used to isolate the high voltage electric field and provide a stable adsorption interface to ensure that the adsorption force is uniformly transmitted to the surface of the adsorbed workpiece.

[0034] The working principle of this embodiment is as follows: During use, the workpiece to be adsorbed is placed on the insulating dielectric layer 3. A high-voltage DC current is applied to the electrostatic adsorption electrode 2 through the high-voltage terminal 4. Electrostatic attraction is generated between the electrostatic adsorption electrode 2 and the workpiece, firmly adsorbing the workpiece onto the surface of the suction cup. Since there is no heating structure inside the suction cup, the surface temperature is the same as the ambient temperature, eliminating temperature gradient interference. Because there is no heating PWM drive circuit or temperature sampling line, the electric field distribution on the surface is not affected by unnecessary circuitry, resulting in uniform adsorption force throughout the entire suction area, stable workpiece positioning, and no displacement.

[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention.

Claims

1. An electrostatic adsorption suction cup, characterized in that, The ceramic substrate (1) includes an electrostatic adsorption electrode (2) embedded inside the ceramic substrate (1), an insulating dielectric layer (3) is laid on the upper surface of the ceramic substrate (1), the electrostatic adsorption electrode (2) is electrically connected to a high voltage terminal (4), and a metal mounting base (5) is fixedly installed at the bottom of the ceramic substrate (1).

2. The electrostatic adsorption suction cup according to claim 1, characterized in that, The ceramic matrix (1) is a few-layer sintered ceramic structure.

3. The electrostatic adsorption suction cup according to claim 1, characterized in that, The high-voltage terminal (4) is equipped with only one set of adsorption electrode wiring.

4. The electrostatic adsorption suction cup according to claim 1, characterized in that, The ceramic matrix (1) is composed entirely of ceramic materials.

5. The electrostatic adsorption suction cup according to claim 1, characterized in that, The insulating dielectric layer (3) covers the electrostatic adsorption electrode (2).

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