Template Pocket Depth Measurement Under Load
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Solution Overview
Problem
The existing methods for measuring the pocket depth of a template used in semiconductor wafer polishing fail to determine whether the target quality can be achieved before the template is bonded to the polishing head, leading to variations in the outer peripheral shape of the wafer and reduced productivity.
Innovation Solution
A method involving a measurement wafer and a pressing jig to measure the depth of the concave portion of the template while applying a load, simulating the polishing state, without attaching the template to the polishing head, allowing for accurate pocket depth measurement and evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the template is bonded to the polishing head before measurement, then the measurement can be performed in a fixed state, but the measurement result does not reflect the actual polishing conditions and leads to variations in wafer outer peripheral shape
Solution Approach 1:
The patent applies preliminary action by measuring the pocket depth of the template before bonding it to the polishing head. The measurement is performed in advance under simulated polishing conditions (with pressing jig applying load), allowing the template to be evaluated and selected before actual polishing. This ensures that only templates meeting the specified pocket depth requirements are used, thereby preventing variations in wafer outer peripheral shape while maintaining measurement accuracy.
2Ease of manufacture
If the template is measured without applying load, then the measurement process is simple, but the measurement does not account for elastic deformation under polishing pressure
Solution Approach 1:
The patent applies parameter changes by introducing a pressing jig that applies a predetermined load to the template during measurement. This changes the physical state of the template from unloaded to loaded, causing elastic deformation that reflects actual polishing conditions. The measurement is then performed on the deformed template, ensuring that the pocket depth value accurately represents the template's behavior during polishing, thereby improving measurement precision while accounting for elastic deformation.
3Reliability
If actual polishing is performed to evaluate template quality, then the wafer flatness can be confirmed, but productivity is reduced due to repeated polishing trials
Solution Approach 1:
The patent applies copying by using a pressing jig to create a simulated polishing condition that replicates the mechanical load and deformation characteristics of actual polishing. Instead of performing actual polishing trials to evaluate template quality, the invention measures the pocket depth under simulated conditions as a proxy for predicting wafer flatness. This copying approach allows quality evaluation without consuming wafers or polishing time, thereby maintaining high reliability while improving productivity.
4Manufacturing precision
If the template thickness is adjusted to control pocket depth, then the outer peripheral shape can be controlled, but the template requires re manufacturing when specifications change
Solution Approach 1:
The patent applies preliminary action by measuring and evaluating the pocket depth of templates before they are bonded to the polishing head. The measurement is performed in advance under simulated polishing conditions, allowing templates to be screened and selected based on their actual performance characteristics. This preliminary evaluation eliminates the need for re manufacturing templates when specification adjustments are needed, as the measurement process identifies suitable templates from existing inventory, thereby maintaining manufacturing precision while improving ease of manufacture.
Data Source
AI summary
A method for measuring a template includes: preparing a measurement wafer and measuring a thickness of the measurement wafer; mounting the template on a reference plane; housing the measurement wafer in the concave portion of the template; measuring heights of the annular member and the measurement wafer from the reference plane in a state where a load is applied to the annular member of the template and the measurement wafer by using a pressing jig; and calculating a depth of the concave portion of the template in the state where the load is applied by using the pressing jig from the measured thickness of the measurement wafer and the heights of the annular member and the measurement wafer. Consequently, it is possible to measure the depth of the concave portion of the template in a state closer to a state during polishing than that realized by a conventional measuring method.