Ceramics Substrate via Bonding Strength
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Solution Overview
Problem
Ceramics substrates used in electrostatic chucks for semiconductor manufacturing often have reduced insulation resistance at elevated temperatures due to the presence of sintering aids, which can compromise the bonding strength between the substrate body and vias, leading to inadequate retention of wafers during processing.
Innovation Solution
A ceramics substrate is developed with a substrate body made of sintering aid-free aluminum oxide, where the vias and electrostatic electrodes are formed using electric conductor pastes containing molybdenum, nickel oxide, and silicon dioxide, enhancing bonding strength without the need for sintering aids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sintering aid is contained in alumina ceramics, then sintering process is facilitated, but insulation resistance decreases at elevated temperatures
Solution Approach 1:
The invention extracts and removes sintering aids from the alumina ceramics composition to eliminate the source of insulation resistance degradation at elevated temperatures, while maintaining sintering feasibility through alternative means
Solution Approach 2:
The invention changes the chemical composition parameters of the ceramics by using high-purity alumina without sintering aids, and adjusts sintering temperature parameters to achieve proper densification while maintaining electrical insulation properties
2Reliability
If sintering aid-free alumina ceramics is used, then insulation resistance is maintained at elevated temperatures, but bonding strength between substrate body and vias cannot be secured
Solution Approach 1:
The invention introduces an intermediary substance (glass frit or bonding agent) that mediates between the sintering aid-free alumina substrate and the vias, providing bonding functionality without compromising the insulation resistance of the substrate body
Solution Approach 2:
The invention creates a composite structure where sintering aid-free alumina is combined with bonding-promoting materials at the interface regions, achieving both high insulation resistance in the bulk and strong bonding at the via-substrate interfaces
3Reliability
If electric conductor paste containing only molybdenum is used, then electrical conductivity is achieved, but bonding strength with substrate body is insufficient
Solution Approach 1:
The invention creates a composite electric conductor paste material combining molybdenum powder with glass frit and/or bonding agents, where molybdenum provides electrical conductivity and the additional components provide bonding strength to the substrate body
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 configuration improves the bonding strength between the substrate body and vias, maintaining high insulation resistance across temperature variations and ensuring effective retention of wafers during semiconductor processing.
Implementation Method 1
a substrate fixing device that adsorbs and retains a wafer by an electrostatic chuck mounted on a base plate
Implementation Method 2
an electrically conductive paste containing metal powder high in melting point such as tungsten (W), molybdenum (Mo) or a molybdenum-manganese (Mo—Mn) alloy, a resin binder, etc. is formed on a ceramics green sheet by a screen printing method or the like, and fired
Data Source
AI summary
A ceramics substrate includes: a substrate body; an electric conductor layer that is built in the substrate body; and a via that is built in the substrate body to be electrically connected to the electric conductor layer. The substrate body is made of ceramics containing aluminum oxide. The via is made of a fired body of an electric conductor paste. The electric conductor paste contains molybdenum as a main component and further contains nickel oxide, aluminum oxide, and silicon dioxide.