Cap-type electrostatic chuck and low-temperature curing manufacturing method

Abstract

This invention provides a cap-shaped electrostatic chuck and its low-temperature curing manufacturing method. The method includes: forming a pocket groove and an isolation ring on the lower surface of a dielectric layer made of ceramic; placing an electrode at the bottom of the groove and depositing an insulating film on the electrode surface; filling the groove with dielectric material and removing air bubbles; curing at a temperature not exceeding a preset temperature to form a cured lower dielectric layer; then processing its thickness and flatness; and fixing the lower dielectric layer and the bottom surface of the isolation ring to a metal base through an adhesive layer. Because a dielectric material that can be cured under lower than conventional high-temperature sintering conditions is used, ceramic thermal deformation and electrode damage can be effectively avoided, and the reliability and lifespan of the electrostatic chuck can be improved. This invention also discloses a structure for a cap-shaped electrostatic chuck, which features a low-temperature cured lower dielectric layer and an improved packaging structure, suitable for semiconductor manufacturing equipment.

Claims

1. A low-temperature curing manufacturing method for a cap-shaped electrostatic chuck, comprising the following steps: Step 1: Preparing an upper dielectric layer, forming a downward-opening pocket groove on the lower surface of the upper dielectric layer, and forming a downward-protruding isolation ring at the edge of the pocket groove; Step 2: Forming an electrode at the bottom of one of the pocket grooves; Step 3: Depositing at least one insulating film on the surface of the electrode for electrical insulation and protection; Step 4: Microstructuring the inner wall of one of the pocket grooves to form an equidistant microgroove or honeycomb structure, filling the pocket groove with a dielectric material, and removing one air bubble inside the dielectric material; Step 5: Curing the dielectric material at a preset temperature to form a cured lower dielectric layer, and selectively curing to give the center and edge of the lower dielectric layer different moduli; Step 6: Processing the bottom surface of the cured lower dielectric layer and the isolation ring to achieve a certain thickness and a certain flatness. Step 7: Fix the bottom surface of the lower dielectric layer and the bottom surface of the isolation ring to a metal base through an adhesive layer.

2. The low-temperature curing manufacturing method for the cap-shaped electrostatic chuck as described in claim 1, wherein, In step 4, the dielectric material is prepared as follows: A. Select a substrate, which is one of polyimide (PI), epoxy resin, or elastomer, and add 30% to 45% of filler, wherein the filler is selected from boron nitride (BN) or aluminum nitride (AlN); B. Place the substrate and the filler in a vacuum planetary stirrer and stir for 10 to 20 minutes at a vacuum of –0.08 MPa to –0.095 MPa; C. Control the viscosity of the resulting mixture to be 2 to 15 Pa·s at 25 °C; D. Make the dielectric material have a volume resistivity of 10⁷ to 10¹⁵ ohm·cm and a thermal conductivity of 0.1 to 4.0 watts per meter Kelvin (W / m·K).

3. The low-temperature curing manufacturing method for the cap-shaped electrostatic chuck as described in claim 1, wherein, The preset temperature is no more than 400℃.

4. The low-temperature curing manufacturing method for the cap-shaped electrostatic chuck as described in claim 1, wherein, The electrode is formed from one of nickel (Ni), tungsten (W), titanium (Ti), or an alloy thereof.

5. The low-temperature curing manufacturing method for the cap-shaped electrostatic chuck as described in claim 1, wherein, The insulating film is formed from one of yttrium oxide (Y₂O₃), aluminum oxide (Al₂O₃), or polytetrafluoroethylene (PTFE) or a composite layer thereof.

6. The low-temperature curing manufacturing method for the cap-shaped electrostatic chuck as described in claim 2, wherein, The dielectric material is formed from one or a mixture of polyimide, epoxy resin, or other adhesives.

7. The low-temperature curing manufacturing method for the cap-shaped electrostatic chuck as described in claim 1, wherein, The bubble is removed by ultrasonic vibration at a frequency of 20–40 kHz.

8. The low-temperature curing manufacturing method for the cap-shaped electrostatic chuck as described in claim 1, wherein, The bottom surface of the lower dielectric layer is at the same height as the bottom surface of the isolation ring.

9. A low-temperature curing manufacturing method for the cap-shaped electrostatic chuck as described in claim 1, wherein, One of the adhesive layers has a thickness between 20 micrometers (µm) and 80 micrometers (µm).

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