Electrostatic Chuck Via Connection Using Conductive Silicone Pads
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Solution Overview
Problem
Conventional electrostatic chucks experience poor electrical contact and thermal stress due to gaps and material expansion, leading to delamination and cracks, as a result of the use of solid-state conductive vias and polyimide layers with different thermal expansion coefficients.
Innovation Solution
The use of conductive silicone pads to electrically connect vias and electrodes, which are formed by applying liquid conductive silicone, providing close contact and alleviating thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid-state conductive vias and CCLs are used to electrically connect electrodes, then electrical connection is achieved, but gaps form at contact portions causing poor contact and short-circuits
Solution Approach 1:
The patent changes the physical state of the conductive material from solid (CCL) to liquid (conductive silicone). The liquid conductive silicone is applied to fill gaps and form intimate contact with the via, ensuring reliable electrical connection without the gap problems associated with solid-state CCLs.
Solution Approach 2:
The conductive silicone acts as an intermediary material between the via and the external connection. It fills the gap and provides a reliable conductive path, mediating the electrical connection in a way that solid CCL cannot due to its rigid nature.
2Reliability
If CCL with polyimide layer is used for electrical connection, then insulation is provided, but thermal expansion mismatch causes poor contact and delamination
Solution Approach 1:
The patent changes the material properties of the conductive medium from solid polyimide-based CCL to liquid conductive silicone. The liquid silicone has better thermal expansion characteristics that match the ceramic substrate, maintaining stable contact across temperature variations from -100°C to 200°C.
Solution Approach 2:
The conductive silicone forms a flexible conductive layer that can accommodate thermal expansion and contraction of the ceramic substrate without breaking contact. This flexibility allows the material to maintain intimate contact with the via throughout the operating temperature range.
3Strength
If ceramic plate and base are bonded with silicone resin, then thermal stress is distributed, but adding CCL hinders stress distribution causing delamination and cracks
Solution Approach 1:
The patent removes the CCL layer from the bonding structure, extracting the problematic element that hindered stress distribution. The electrical connection function is achieved through liquid conductive silicone applied directly to the via, eliminating the need for CCL and its polyimide insulation layer in the bonding interface.
Solution Approach 2:
The patent merges the electrical connection function and the stress distribution function into a single material system. The liquid conductive silicone provides both electrical conductivity and flexible stress accommodation, while the silicone resin bonding layer uniformly distributes thermal stress without the interference of rigid CCL structures.
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
Prevents short-circuits and maintains stable electrical connections while relieving thermal stress, ensuring reliable operation across temperature variations.
Implementation Method 1
a conductive silicone pad disposed on the second surface of the ceramic plate and bonded to the one end of the first via and the one end of the second via to electrically connect the first via and the second via
Implementation Method 2
since the ceramic plate 12 is used in an environment having a large temperature variation, such as −100° C. to 200° C., the polyimide of the CCL 20 may expand and contract
Implementation Method 3
the silicone resin adhesive between the ceramic plate 12 and the base 14 serves to distribute and relieve such stress
Data Source
AI summary
Provided is an electrostatic chuck including a ceramic plate having a first surface and a second surface. The ceramic plate includes: a plurality of ceramic layers; a first electrode and a second electrode disposed between the plurality of ceramic layers; a first via and a second via penetrating some of the ceramic layers, the first via being connected to the first electrode, the second via being connected to the second electrode, and one end of the first via and one end of the second via being exposed on the second surface of the ceramic plate; and a conductive silicone pad disposed on the second surface of the ceramic plate and bonded to the one end of the first via and the one end of the second via to electrically connect the first via and the second via.