Double-Side Polishing Carrier Insert Uniformity
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Solution Overview
Problem
Double-side polishing apparatuses experience variations in wafer flatness due to non-uniform carriers, primarily caused by variations in insert thickness and misalignment between the carrier body and insert.
Innovation Solution
A method involving a lapping process and polishing process for the insert, followed by engagement with the carrier body and sticking while applying a load perpendicular to the carrier's main surfaces, ensures uniformity by reducing insert thickness variation and misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If carriers are made with inserts attached to protect wafer edges, then wafer edge damage is prevented, but variation in insert thickness and misalignment occur causing wafer flatness variation
Solution Approach 1:
The insert undergoes lapping and polishing processes before being attached to the carrier body, pre-establishing a uniform thickness and flat surface. This preliminary action ensures that when multiple carriers are used for batch wafer polishing, the inserts maintain consistent dimensions, preventing wafer flatness variation while still protecting wafer edges.
Solution Approach 2:
The lapping and polishing processes change the physical parameters of the insert, specifically its thickness uniformity and surface flatness. By controlling these parameters to be within tight tolerances before attachment, the subsequent carrier assembly produces uniform wafer flatness results while maintaining edge protection functionality.
2Productivity
If multiple wafers are polished simultaneously in batch process, then productivity is improved, but variation in wafer flatness occurs due to carrier non-uniformity
Solution Approach 1:
Each insert is pre-processed through lapping and polishing to establish uniform thickness and flatness before being attached to the carrier body. This preliminary standardization ensures that when multiple carriers are used simultaneously in batch processing, all inserts contribute equally to maintaining consistent wafer flatness across all wafers being polished at once.
Solution Approach 2:
The lapping and polishing processes transform the insert parameters (thickness, flatness) to fall within strict tolerances. This parameter control allows multiple carriers to be used in parallel without introducing flatness variation, thereby enabling high-productivity batch processing while maintaining precision.
3Device complexity
If insert is engaged with holding hole without preliminary processing, then manufacturing complexity is reduced, but insert thickness variation and misalignment increase
Solution Approach 1:
The insert is subjected to lapping and polishing processes before engagement with the holding hole. This preliminary processing step, while adding to the manufacturing process, establishes uniform insert thickness and flatness that prevents misalignment and thickness variation issues during subsequent carrier assembly and use.
Solution Approach 2:
Through lapping and polishing, the insert's physical parameters (thickness uniformity, surface flatness) are changed to meet strict tolerances. This parameter control compensates for the added process complexity by ensuring high precision in the final carrier assembly, making the overall process worthwhile.
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 approach produces carriers with high uniformity, which in turn reduces the variation in flatness of wafers polished in batch processes, resulting in consistently high-quality polished wafers.
Implementation Method 1
performing a lapping process and a polishing process on the insert
Implementation Method 2
performing a lapping process and a polishing process on the insert
Implementation Method 3
sticking the insert to the holding hole
Data Source
AI summary
A method of producing a carrier for use in a double-side polishing apparatus, the method including engaging an insert with a holding hole formed in a carrier body and sticking the insert to the holding hole, the carrier body being configured to be disposed between upper and lower turn tables to which polishing pads are attached of the double-side polishing apparatus, the holding hole being configured to hold a wafer during polishing, the insert being configured to contact an edge of the wafer to be held, the method including: performing a lapping process and a polishing process on the insert; engaging the insert subjected to the lapping process and the polishing process with the holding hole of the carrier body; and sticking and drying the engaged insert while applying a load to the insert in a direction perpendicular to main surfaces of the carrier body.