Multi-Step Polishing Method for Semiconductor Wafers
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Solution Overview
Problem
The existing multi-step chemical mechanical polishing (CMP) process for semiconductor wafers is hindered by the need to frequently measure surface conditions between polishing steps, which increases the total polishing time and reduces throughput due to the time-consuming process of removing, cleaning, and re-measuring substrates.
Innovation Solution
A method and apparatus that allow for sequential multi-step polishing with reduced surface condition measurements by using preset conditions for the first polishing process and modifying subsequent polishing conditions based on initial measurements, enabling successive polishing without intermediate ITM measurements, thereby optimizing polishing conditions and increasing throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If surface conditions are measured between polishing steps using ITM, then polishing precision is improved, but total polishing time increases and throughput decreases
Solution Approach 1:
The patent applies preliminary action by measuring the initial surface conditions of substrates before the polishing process begins. These preliminary measurements are then used to determine appropriate polishing conditions for multiple substrates in sequence, eliminating the need for intermediate measurements between polishing steps. This approach maintains polishing precision while significantly reducing the time lost to repeated measurements and substrate handling operations.
Solution Approach 2:
The patent implements continuity of useful action by enabling uninterrupted polishing operations. Once initial measurements are taken and polishing conditions are set, substrates can be polished continuously without being removed for intermediate measurements. The polishing process maintains continuous operation with substrates being processed in sequence, eliminating the cyclic interruptions caused by traditional measurement- polishing- measurement cycles.
2Measurement precision
If substrates are removed, cleaned, and re-measured between polishing steps, then measurement accuracy is improved, but process time increases
Solution Approach 1:
The patent performs surface condition measurements as a preliminary action before the polishing process begins. These initial measurements provide sufficient data to determine polishing conditions for multiple substrates, eliminating the need for repeated measurements between polishing steps. This approach maintains measurement accuracy while avoiding the time-consuming cycles of removal, cleaning, and re-measurement.
3Manufacturing precision
If multi-step polishing is carried out with frequent measurements, then polishing quality is improved, but operational complexity increases
Solution Approach 1:
The patent simplifies the multi-step polishing process by performing preliminary measurements and condition设定 before polishing begins. The control system uses these preliminary data to automatically determine polishing conditions for subsequent substrates, reducing the need for complex intermediate measurements and manual interventions. This maintains polishing quality while significantly reducing operational complexity.
Solution Approach 2:
The patent implements a feedback mechanism where initial measurement results are used to determine polishing conditions that are then applied to subsequent substrates. The control system continuously references the preliminary measurement data to maintain consistent polishing quality across multiple substrates without requiring repeated measurements, thereby simplifying the overall process complexity.
Data Source
AI summary
A polishing method that carries out a multi-step polishing process with improved polishing conditions (polishing recipe) while omitting measurement of the surface conditions of a substrate, as carried out between polishing steps thereby increasing the throughput. The polishing method for polishing workpieces by repeating the sequential operations of taking a workpiece out of a cassette in which a plurality of workpieces are stored, carrying out multi-step polishing of a surface of the workpiece and returning the workpiece to the cassette, includes carrying out one of the following two polishing processes for the workpiece taken out of the cassette: a first polishing process comprising carrying out the multi-step polishing under preset conditions and measurement of the surface of the workpiece before and after each polishing step; and a second polishing process comprising carrying out a predetermined step of the multi-step polishing under polishing conditions which have been modified based on the results of the measurement.