Vitrified Bond Grindstone Composition for Low-Temperature Sintering
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Solution Overview
Problem
Vitrified bond grindstones used in grinding apparatuses for semiconductor wafers face issues with abrasive grain deterioration due to high sintering temperatures, leading to reduced performance and inadequate self-sharpening, and are prone to water resistance and strength deficiencies when sintering assistant oxides like Na2O, CaO, K2O, and BaO are used, which are highly soluble in water.
Innovation Solution
Incorporating zinc oxide (ZnO) in a content of 11 to 15 wt% and optionally zirconium dioxide (ZrO2) into the bonding material, along with SiO2 as the main constituent, allows for a lower sintering temperature and enhances mechanical strength and water resistance, preventing abrasive grain deterioration and ensuring effective self-sharpening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sintering assistant oxides (Na2O, CaO, K2O, BaO) are added to lower sintering temperature, then self-sharpening occurs and abrasive grain deterioration is prevented, but water resistance and strength deteriorate due to high solubility in water
Solution Approach 1:
ZnO acts as an intermediary substance that mediates between the sintering assistant oxides and water. It reduces the solubility of sintering assistant oxides in water while maintaining the low sintering temperature benefit, thus preventing the harmful effect of water resistance deterioration
Solution Approach 2:
The bonding material is formulated as a composite containing multiple oxides (SiO2, ZnO, and sintering assistant oxides) in specific proportions. This composite structure allows the material to simultaneously achieve low sintering temperature, adequate self-sharpening, and improved water resistance through the synergistic effect of different components
2Reliability
If sintering temperature is lowered to prevent abrasive grain deterioration, then self-sharpening is enhanced, but mechanical strength and water resistance decrease
Solution Approach 1:
The chemical composition parameters of the bonding material are changed by adding ZnO at 11-15 wt% and adjusting sintering assistant oxide content to 20-29 wt%. This parameter change enables the material to achieve low sintering temperature (900-1000°C) while maintaining adequate mechanical strength and water resistance
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 modified grindstones maintain sufficient mechanical strength and water resistance, enabling effective grinding performance with appropriate self-sharpening, even at lower sintering temperatures.
Implementation Method 1
the mixed material being sintered. Since the sintering temperature in this instance is a high temperature on the order of 1,200° C. to 1, 300° C.
Implementation Method 2
a bonding material (a mixture of silicon dioxide (SiO2), aluminum oxide (Al2O3), and boron oxide (B2O3)) containing a vitreous material as a main constituent
Implementation Method 3
there occurs shelf-sharpening in which the bonding material is consumed appropriately and unused abrasive grains contained in the grindstone appear one after another from the bonding material
Data Source
AI summary
A vitrified bond grindstone includes abrasive grains and a bonding material for fixing the abrasive grains, the bonding material includes a parent material containing SiO2 as a main constituent, a sintering assistant oxide, and ZnO, and the content of ZnO is 11 to 15 wt % in weight ratio based on the bonding material. Preferably, the content of the sintering assistant oxide is 20 to 29 wt % in weight ratio based on the bonding material.