Semiconductor Substrate Friction Reduction via HMDS Coating

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Friction between semiconductor substrates and wafer tables leads to damage and unevenness, necessitating frequent wafer table replacement and causing issues with wafer clamping, while low coefficient of static friction materials introduce critical dimension variation and scum defects.

Innovation Solution

Converting the surface of semiconductor substrates from a higher to a lower coefficient of static friction by applying a friction-reducing material like hexamethyldisilazane (HMDS) to one side, allowing the substrate to be placed on the wafer table with the lower friction side facing down, and using a photoresist layer on the opposing side to reduce friction and prevent material transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If low coefficient of static friction materials are applied to the semiconductor substrate, then friction between substrate and wafer table is reduced, but critical dimension variation and scum defects occur

Engineering Contradiction:

ImprovefrictionVSAvoidcritical dimension variation

Core Design Contradiction:

ForceVSManufacturing precision

Solution Approach 1:

The patent changes the coefficient of static friction parameter of the substrate surface by applying a friction-reducing material. This modifies the surface properties to reduce friction force between substrate and wafer table, while controlling the application to avoid critical dimension variation and scum defects

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

A friction-reducing material is introduced as an intermediary substance between the substrate and wafer table. This mediator reduces direct friction contact while being applied in a controlled manner to prevent defects on the photoresist side

Inventive Principle:

Principle #24Intermediary (Mediator)

2Force

If low coefficient of static friction materials are applied to the semiconductor substrate, then friction between substrate and wafer table is reduced, but scum defects occur

Engineering Contradiction:

ImprovefrictionVSAvoidscum defects

Core Design Contradiction:

ForceVSObject-generated harmful factors

Solution Approach 1:

The friction-reducing material is applied selectively to specific regions of the substrate surface rather than uniformly across all surfaces. This local application reduces friction where needed while preventing material contamination that would cause scum defects on the photoresist-coated side

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The friction-reducing material serves as a controlled intermediary layer that reduces friction without transferring to the photoresist side, preventing scum defect formation while achieving the desired friction reduction

Inventive Principle:

Principle #24Intermediary (Mediator)

3Duration of action of stationary object

If friction between substrate and wafer table is high, then wafer table damage occurs frequently, but applying friction-reducing materials causes critical dimension variation

Engineering Contradiction:

Improvewafer table lifeVSAvoidcritical dimension variation

Core Design Contradiction:

Duration of action of stationary objectVSManufacturing precision

Solution Approach 1:

The coefficient of static friction parameter is modified by applying a friction-reducing material to the substrate, reducing wear on the wafer table and extending its operational life, while controlling application parameters to avoid critical dimension variation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The friction-reducing material is applied to the substrate in advance before wafer table contact, pre-establishing a low-friction interface that protects the wafer table from damage during subsequent processing operations

Inventive Principle:

Principle #10Preliminary action

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 method extends wafer table life, reduces scratches and surface irregularities, decreases critical dimension variation, and minimizes scum/residue defects, improving wafer clamping and table flatness, and prolongs wafer table life from 2 months to 12 months in mass production.

Implementation Method 1

converting a first main side of the semiconductor substrate having a first coefficient of static friction relative to a surface of a wafer table to a second coefficient of static friction relative to the surface of the wafer table, wherein the second coefficient of static friction is less than the first coefficient of static friction

Methodology Applied

Scientific EffectFriction coefficient conversion: Friction

Data Source

PatentUS11127583B2Method of treating semiconductor substrate

Publication Date: 2021.09.21 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method of treating a semiconductor substrate includes converting a first main side of the semiconductor substrate having a first coefficient of static friction relative to a surface of a wafer table to a second coefficient of static friction relative to the surface of the wafer table, wherein the second coefficient of static friction is less than the first coefficient of static friction. A photoresist layer is applied over a second main side of the semiconductor substrate having the first coefficient of static friction. The second main side opposes the first main side. The semiconductor substrate is placed on the wafer table so that the first main side of the semiconductor substrate faces the wafer table.