Dual Cup-Wheel Grinding for Accurate Large-Substrate Finishing

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Solution Overview

Problem

Existing substrate grinding methods struggle to efficiently and accurately grind large-size mounting substrates with warpage, such as wafer level packages (WLP) and panel level packages (PLP), due to increased processing time, excessive wear on grinding wheels, and the need for multiple grinding devices, which complicates high-accuracy finish grinding.

Innovation Solution

A substrate grinding device and method utilizing a cup wheel-type first and second grinding wheels that simultaneously grind the substrate without changing its position, with the first wheel performing coarse grinding and the second wheel performing finish grinding, reducing the size of the device and grinding time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single grinding wheel is used for substrate grinding, then the device complexity is reduced, but the manufacturing precision deteriorates due to inability to perform both coarse and finish grinding simultaneously

Engineering Contradiction:

Improvenumber of grinding wheelsVSAvoidgrinding accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent combines two grinding wheels (first grinding wheel for coarse grinding and second grinding wheel for finish grinding) into a single substrate grinding device, allowing both coarse and finish grinding to be performed simultaneously on the same substrate without requiring separate devices or sequential processing steps

Inventive Principle:

Principle #5Merging (Combining)

2Manufacturing precision

If multiple grinding devices are used for coarse and finish grinding, then the manufacturing precision is improved, but the device complexity increases

Engineering Contradiction:

Improvegrinding accuracyVSAvoidnumber of grinding devices

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the functionality of separate coarse grinding device and finish grinding device into a single integrated substrate grinding device with multiple grinding wheels, eliminating the need for multiple independent devices while maintaining both coarse and finish grinding capabilities

Inventive Principle:

Principle #5Merging (Combining)

3Manufacturing precision

If sequential grinding (coarse then finish) is performed, then the manufacturing precision is improved, but the processing time increases

Engineering Contradiction:

Improvegrinding accuracyVSAvoidgrinding time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent enables continuous simultaneous grinding by operating both the first grinding wheel (coarse grinding) and second grinding wheel (finish grinding) at the same time on the substrate, eliminating the idle time between sequential coarse and finish grinding operations

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The first grinding wheel performs coarse grinding to remove material and prepare the substrate surface in advance, while the second grinding wheel simultaneously performs finish grinding, so that by the time coarse grinding is complete, finish grinding is already underway or complete

Inventive Principle:

Principle #10Preliminary action

4Ease of manufacture

If traditional substrate grinding method is used, then the processing is simple, but the productivity deteriorates due to long processing time

Engineering Contradiction:

Improveprocess simplicityVSAvoidgrinding efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent maintains process simplicity while dramatically improving productivity by enabling continuous simultaneous grinding with multiple wheels, where both coarse and finish grinding operations occur concurrently rather than sequentially, reducing total processing time without complicating the overall process flow

Inventive Principle:

Principle #20Continuity of useful 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

The method allows for efficient and high-accuracy grinding of large-size substrates with reduced grinding time and grinding wheel wear, achieving a ½ reduction in processing time and ⅓ reduction in wheel costs compared to single-wheel grinding methods.

Implementation Method 1

a work table rotatable with the work table sucking and holding a substrate

Methodology Applied

Scientific EffectSuction: Suction

Implementation Method 2

a cup wheel-type first grinding wheel configured to grind the rotating substrate while rotating

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentUS12358095B2Substrate grinding device and substrate grinding method

Publication Date: 2025.07.15 OKAMOTO MACHINE TOOL WORKS LTD

AI summary

Provided is a substrate grinding device including: a work table rotatable with the work table sucking and holding a substrate; a cup wheel-type first grinding wheel configured to grind the rotating substrate while rotating, the substrate being held by the work table; and a cup wheel-type second grinding wheel configured to grind the substrate along with grinding by the first grinding wheel while rotating in a close vicinity of the substrate.