Quartz Wafer Single-Sided Lapping for Thin Large-Area Surface Accuracy

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Solution Overview

Problem

Existing two-sided lapping methods for quartz crystal wafers with large areas and thin thickness face challenges due to increased resistance and damage during processing, making them unsuitable for ultra-precision processing.

Innovation Solution

A single-sided lapping device with a base, supporting arm assembly, lapping plate, swivel gantry, rotating motor, loading block, and plate-adjusting ring, along with a dropper, is used to perform rough and fine lapping on both surfaces of quartz crystal wafers, adjusting pressure and using abrasives like alumina, silicon carbide, and diamond to control surface fineness and damage depth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If two-sided lapping is used for large area thin quartz crystal wafers, then both surfaces can be processed simultaneously improving productivity, but the close contact increases resistance and causes damage to the thin wafer

Engineering Contradiction:

Improveprocessing efficiencyVSAvoidwafer integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent divides the simultaneous two-sided lapping process into sequential single-sided lapping operations. The wafer is first lapped on one surface, then flipped and lapped on the opposite surface. This segmentation eliminates the harmful close contact between both surfaces and the lapping plate that causes damage to thin wafers, while still achieving complete surface processing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of maintaining continuous two-sided contact with the lapping plate, the patent inverts the approach by processing one side at a time. The wafer is flipped between lapping operations, reversing the contact pattern and eliminating the resistance and damage issues associated with simultaneous two-sided processing.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If single-sided lapping is used to avoid damage to thin wafers, then wafer integrity is maintained, but processing both surfaces requires separate operations reducing productivity

Engineering Contradiction:

Improvewafer integrityVSAvoidprocessing efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by performing rough lapping on one surface before flipping to the other surface. The loading block is prepared with adhesive material in advance, and the wafer is secured before each lapping operation. This preliminary preparation enables efficient sequential processing without compromising wafer integrity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent maintains continuity of useful action by systematically processing both surfaces through sequential single-sided lapping. The wafer is flipped and repositioned without leaving any surface unprocessed, ensuring continuous productive work while avoiding the damage risks of simultaneous two-sided processing.

Inventive Principle:

Principle #20Continuity of useful action

3Reliability

If adhesive material is used to secure the wafer to the loading block, then wafer retention is improved, but adhesive error and deformation occur during processing

Engineering Contradiction:

Improvewafer retentionVSAvoidsurface accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by carefully controlling the adhesive material properties and application parameters. The adhesive layer thickness, curing temperature, and pressure are optimized to achieve secure wafer retention while minimizing adhesive error and deformation. This parameter optimization resolves the contradiction between retention and precision.

Inventive Principle:

Principle #35Parameter changes

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 device effectively removes surface defects and achieves the required surface shape and thickness precision for large area quartz crystal wafers, enhancing processing accuracy and reliability.

Implementation Method 1

The swing arm is driven to swing left and right by the swing arm motor and the swing arm shaft

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

the plate-adjusting ring and the loading block encased in the plate-adjusting ring are driven by the roller on the swing arm to move on the lapping plate, realizing the lapping of the quartz crystal wafer surface

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 3

using abrasives like alumina, silicon carbide, and diamond to control surface fineness and damage depth

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentUS12551983B2Large area quartz crystal wafer lapping device and a lapping method thereof

Publication Date: 2026.02.17 TANGSHAN GUOXIN JINGYUAN ELECTRONICS CO LTD

AI summary

A large area quartz crystal wafer lapping device, provided with a base, a supporting arm assembly, a lapping plate, a swivel gantry, a rotating motor, a loading block and a plate-Adjusting ring; The supporting arm assembly comprises a swing arm, a swing arm shaft, a swing arm motor, an adjustable arm and a roller; The swivel gantry is driven to rotate by the rotating motor; The loading block is encased in the plate-Adjusting ring, and a quartz crystal wafer is bonded to the bottom surface of the loading block. In the invention, through the improved design of material removal and wafer retention, the processing surface shape of large area quartz crystal wafer can meet the design requirements.