Electrostatic Chuck Joining Layer for Stable Wafer Temperature
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Solution Overview
Problem
Existing electrostatic chucks fail to maintain an appropriate in-plane temperature distribution of wafers during semiconductor manufacturing processes due to significant changes in the dielectric tangent and heating value of the joining layer, which are influenced by varying operation conditions and alternating electric fields.
Innovation Solution
The electrostatic chuck is designed with a joining layer that maintains a dielectric tangent fluctuation within a specific range (50% to 200% of the reference value) even when the temperature changes from 20°C to −60°C, using materials like silicone or polyimide-based adhesives to stabilize the dielectric tangent and heating value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a high-frequency voltage is applied to generate plasma, then plasma generation is achieved, but the heating value of the joining layer changes significantly due to dielectric tangent changes with temperature
Solution Approach 1:
The patent selects a joining layer material whose dielectric tangent remains stable across a wide temperature range by changing the material parameters. Specifically, it uses a joining layer made of a material with a dielectric tangent of 0.02 or less at room temperature, ensuring that the heating value does not significantly change even when temperature varies from room temperature to −60°C during plasma processing.
Solution Approach 2:
The patent employs a composite structure where the joining layer is formed by combining a base material with filler particles. This composite approach allows optimization of the dielectric properties - the filler material is selected to have a dielectric tangent of 0.02 or less, and the composite structure maintains stable dielectric characteristics across temperature variations, resolving the contradiction between temperature control and material stability.
2Manufacturing precision
If the dielectric tangent of the joining layer changes with temperature, then the heating value changes, but this causes inappropriate in-plane temperature distribution of the wafer
Solution Approach 1:
The patent changes the dielectric parameter of the joining layer by selecting materials with specific properties. The joining layer is designed to have a dielectric tangent of 0.02 or less at room temperature, which ensures that even when temperature changes occur during processing, the dielectric tangent remains stable and the heating value does not vary significantly, thereby maintaining appropriate in-plane temperature distribution.
Solution Approach 2:
The patent applies local quality control by specifically targeting the joining layer's dielectric properties. Rather than controlling the entire electrostatic chuck system, the invention focuses on the local property of the joining layer material - selecting and formulating a joining layer with optimized dielectric characteristics (tangent ≤ 0.02) that locally stabilizes the temperature distribution across the wafer surface.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design ensures consistent and appropriate in-plane temperature distribution of the wafer by minimizing fluctuations in the dielectric tangent and heating value, thus maintaining optimal cooling performance under varying conditions.
Implementation Method 1
When a voltage is applied to the attraction electrode, an electrostatic force is generated, and the wafer placed on the dielectric substrate is attracted and held. When plasma is to be generated in the semiconductor manufacturing apparatus, a high-frequency voltage is applied between a pair of electrodes. According to this, an alternating electric field is applied to each section of the electrostatic chuck.
Implementation Method 2
When a temperature of the joining layer changes according to an operation condition of the semiconductor manufacturing apparatus or the like, along with that change, a value of a dielectric tangent of the joining layer also changes. When the value of the dielectric tangent changes, since a heating value of the joining layer also changes due to the application of the alternating electric field, the in-plane temperature distribution of the wafer is affected by that change.
Data Source
AI summary
An electrostatic chuck 10 includes a dielectric substrate 100, a base plate 200 which supports the dielectric substrate 100, and a joining layer 300 which joins the dielectric substrate 100 and the base plate 200. A value of a dielectric tangent of the joining layer 300 when a temperature of the joining layer 300 is 20° C. is set as a reference value. In the electrostatic chuck 10, when the temperature of the joining layer 300 has changed from 20° C. to −60° C., a range in which the value of the dielectric tangent of the joining layer 300 fluctuates falls within a range from 50% to 200% of the reference value.