Polishing Head Elastic Ring Structure for Uniform Wafer Contact

The patent applies this principle by using an elastic member (such as an elastic ring or elastic layer) as the contact surface between the pressing tool and polishing tool. The elastic material naturally conforms to the polishing tool surface, eliminating irregularities caused by machining limits and ensuring uniform pressing force distribution without requiring ultra-precise rigid surface machining.

The patent changes the physical state of the contact surface from rigid to elastic. By selecting elastic members with appropriate elasticity parameters (such as Shore hardness), the contact surface can deform to match the polishing tool geometry, achieving smooth contact through material property selection rather than machining precision.

The elastic member acts as a flexible interface that ensures complete contact between the polishing tool and substrate by conforming to the polishing tool surface geometry, eliminating non-contact regions and improving polishing reliability.

The elastic member is pre-compressed between the pressing tool and polishing tool, creating preliminary contact pressure that ensures the polishing tool maintains uniform contact with the substrate throughout the polishing process, preventing non-contact regions before they can form.

Instead of machining a rigid surface to high precision, the patent uses an elastic member that naturally forms a smooth contact surface through its material properties. This approach is easier to manufacture because it requires selecting and installing an elastic component rather than performing complex high-precision machining operations.

The patent changes the approach from achieving smoothness through machining parameters to achieving smoothness through material parameters. By selecting elastic materials with appropriate properties (such as Shore hardness between 40-80), the smooth contact surface is obtained through material selection rather than manufacturing process complexity.