Offset Mechanism for Uniform Substrate Polishing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional chemical mechanical polishing (CMP) techniques struggle to uniformly remove variations in film thickness along the circumferential direction of semiconductor wafers, leading to potential residual thickness variations.
Innovation Solution
A substrate holding device with an elastic membrane, carrier, retaining ring, and offset mechanism, controlled by a control device that determines eccentricity and applies pressing forces to offset the carrier, ensuring uniform polishing by adjusting the pressure chambers and rotational torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CMP techniques are used to polish the wafer, then the polishing process can be performed, but variations in film thickness along the circumferential direction cannot be eliminated
Solution Approach 1:
The carrier is made movable relative to the retaining ring through an offset mechanism, allowing dynamic adjustment of the carrier's position. This enables the system to adapt to varying film thickness distributions by repositioning the carrier to compensate for thickness variations, thereby achieving uniform polishing without requiring complex multi-component systems
Solution Approach 2:
The system changes the positional parameter of the carrier relative to the retaining ring to eliminate film thickness variations. By adjusting the carrier's eccentricity and position, the system modifies the pressure distribution across the wafer surface, enabling uniform material removal even when initial film thickness varies circumferentially
2Manufacturing precision
If the carrier is offset relative to the retaining ring, then film thickness variations can be eliminated, but the device structure becomes more complex
Solution Approach 1:
The offset mechanism is divided into multiple independent pressing actuators, each capable of adjusting the carrier's position in specific directions. This segmentation allows the complex positioning task to be broken down into simpler, controllable steps, with each actuator responsible for a portion of the overall positioning function
Solution Approach 2:
The control device receives film thickness distribution information and uses this feedback to determine the required carrier offset. The system calculates the appropriate eccentricity and position based on measured thickness variations, then actuates the pressing members to achieve the desired carrier positioning, creating a closed-loop control system
3Measurement precision
If multiple pressing actuators are used to offset the carrier, then precise positioning can be achieved, but the number of components increases
Solution Approach 1:
Each pressing actuator serves multiple functions: it applies pressing force to the carrier, controls the carrier's position in a specific direction, and contributes to the overall offset mechanism. This multi-functionality reduces the need for separate components for each function, thereby limiting the increase in device complexity while maintaining precise positioning control
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
The solution effectively eliminates film thickness variations by dynamically adjusting the carrier's position relative to the retaining ring, ensuring consistent polishing across the wafer surface, thereby achieving uniform film thickness.
Implementation Method 1
an elastic membrane configured to form at least one pressure chamber for pressing a substrate
Implementation Method 2
an offset mechanism configured to offset the carrier relative to the retaining ring
Implementation Method 3
a tilting structure configured to tilt the retaining ring
Implementation Method 4
a rotational torque transmission mechanism configured to transmit a rotational torque acting on the retaining ring to the carrier
Data Source
AI summary
A substrate holding device capable of eliminating a variation in a film thickness of a substrate is disclosed. The substrate holding device includes an offset mechanism configured to offset a carrier with respect to a retaining ring.