Process Tuning Kit for Semiconductor Wafer Backside Deposition
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Solution Overview
Problem
Chemical deposition processes on semiconductor substrates face challenges with backside deposition, leading to wafer curvature due to stress from film deposition, which existing technologies struggle to minimize effectively.
Innovation Solution
A process tuning kit comprising a carrier ring, horseshoes, and shims is used to support the substrate, allowing for precise adjustment of the offset distance between the substrate and the carrier ring, thereby minimizing backside deposition by using shims of varying thicknesses and horseshoes with specific geometries to optimize the positioning and reduce backside film deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the substrate is placed close to the carrier ring to minimize offset distance, then mechanical stability is improved, but backside deposition increases causing wafer curvature
Solution Approach 1:
The patent introduces a vertical offset dimension between the substrate and carrier ring, moving from direct contact (zero offset) to a controlled distance (e.g., 0.020 inches). This dimensional change allows the substrate to be thermally coupled to the carrier ring for stability while preventing material deposition on the backside by maintaining a gap that excludes the deposition zone.
Solution Approach 2:
The patent uses spacers or offset structures as intermediary elements between the substrate and carrier ring. These intermediaries maintain a controlled distance that prevents backside deposition while preserving mechanical stability through proper structural design, acting as a mediator that resolves the conflict between contact and separation.
2Object-generated harmful factors
If the offset distance between substrate and carrier ring is increased to reduce backside deposition, then backside deposition is minimized, but mechanical stability and thermal coupling are reduced
Solution Approach 1:
The patent optimizes the offset distance to a specific range (e.g., 0.020 inches) that provides sufficient separation to prevent backside deposition while maintaining adequate mechanical and thermal coupling. This precise dimensional control resolves the contradiction by finding the optimal point in the offset dimension.
Solution Approach 2:
The patent systematically varies the offset distance parameter to identify the optimal value that balances backside deposition reduction with mechanical stability. By changing this critical parameter and measuring its effects, the patent determines the specific offset range that resolves the technical contradiction.
3Manufacturing precision
If uniform deposition is achieved across the substrate, then film quality is improved, but backside deposition increases causing stress and curvature
Solution Approach 1:
The patent segments the deposition process into frontside and backside zones by introducing an offset. The carrier ring supports the substrate at a distance that allows frontside deposition to proceed uniformly while excluding the backside from the deposition zone, thereby segmenting the harmful effects from the useful deposition.
Solution Approach 2:
The patent applies local quality control by creating different conditions for frontside and backside of the substrate. The offset structure provides a deposition-friendly environment for the frontside while creating a deposition-free zone for the backside, allowing each surface to have the quality needed for its specific function.
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 significantly reduces backside deposition, achieving a deposition of 50 Å or less at 3 mm from the bevel edge, thereby minimizing wafer curvature and improving the uniformity of film deposition.
Implementation Method 1
A radio frequency (RF) power is applied between the electrodes to excite a process gas or reactor chemistries into a plasma for processing semiconductor substrates in the reaction chamber
Implementation Method 2
chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD)
Data Source
AI summary
A process tuning kit for use in a chemical deposition apparatus wherein the process tuning kit includes a carrier ring, horseshoes and shims. The horseshoes have the same dimensions and the shims are provided in sets with different thicknesses to control the height of the horseshoes with respect to an upper surface of a pedestal assembly on which the horseshoes and shims are mounted. A semiconductor substrate is transported into a vacuum chamber of the chemical deposition apparatus by the carrier ring which is placed on the horseshoes such that minimum contact area supports lift the substrate from the carrier ring and support the substrate at a predetermined offset with respect to an upper surface of the pedestal assembly. During processing of the substrate, backside deposition can be reduced by using shims of desired thickness to control the predetermined offset.