Silicon Wafer Separation via Doped Intermediate Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current techniques for fabricating multi-layered plates and thin wafers in micro-electronics and opto-electronics lack effective methods for separating substrates and superstrates while maintaining structural integrity and performance.
Innovation Solution
A method involving an intermediate layer with extrinsic atoms or molecules, such as phosphorus and boron, is used, where a heat treatment creates micro-bubbles or micro-cavities, weakening the layer and allowing for separation of substrates and superstrates through either applied forces or chemical attack, facilitating the production of silicon wafers and diverse applications like integrated circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If molecular wafer bonding is used to join substrate and superstrate, then bonding strength is improved, but separation difficulty increases
Solution Approach 1:
The intermediate layer is pre-doped with extrinsic atoms (phosphorus, boron) before bonding, so that during subsequent heat treatment these atoms create micro-bubbles that weaken the layer. This preliminary preparation enables easy separation later without compromising the initial bonding strength.
Solution Approach 2:
An intermediate layer composed of doped silica acts as a mediator between the substrate and superstrate. This layer provides sufficient bonding strength when intact, but contains hidden weakness (doped regions) that enable controlled separation when needed, thus resolving the contradiction between strong bonding and easy separation.
2Stability of the object's composition
If intermediate layer is made strong and intact, then structural integrity is improved, but separation capability deteriorates
Solution Approach 1:
The intermediate layer has non-uniform composition: most regions maintain structural integrity, while localized regions contain higher concentrations of extrinsic atoms that create micro-bubbles during heat treatment. This local variation enables both structural integrity and separation capability coexist.
Solution Approach 2:
The intermediate layer's physical and chemical parameters are changed through doping with extrinsic atoms. During heat treatment, these parameter changes cause phase separation and micro-bubble formation, transforming the layer from a strong intact structure to a weakened structure suitable for separation, thus enabling both states at different stages.
3Ease of manufacture
If heat treatment temperature is increased to create micro-bubbles, then separation ease is improved, but risk of substrate damage increases
Solution Approach 1:
The concentration of extrinsic atoms in the intermediate layer is optimized to create micro-bubbles at moderate heat treatment temperatures (typically 400-600°C). This parameter optimization enables sufficient micro-bubble formation for easy separation while keeping the temperature low enough to prevent substrate damage.
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 enables the efficient separation of substrates and superstrates, enhancing the structural integrity and performance of silicon wafers, and allows for the creation of thin wafers suitable for integrated electronic and opto-electronic circuits with reduced capacitance and potential for cooling fluid channels.
Implementation Method 1
applying a heat treatment to said structure so that, in the temperature range of said heat treatment, the intermediate layer is plastically deformable
Implementation Method 2
the intermediate layer is plastically deformable
Implementation Method 3
the presence of the selected extrinsic atoms or molecules in the selected base material causes the irreversible formation of micro-bubbles or micro-cavities in the intermediate layer
Data Source
AI summary
Method for fabricating a structure in the form of a plate, and structure in the form of a plate, in particular formed from silicon, including at least one substrate, a superstrate and at least one intermediate layer interposed between the substrate and the superstrate, in which the intermediate layer comprises at least one base material having distributed therein atoms or molecules termed extrinsic atoms or molecules which differ from the atoms or molecules of the base material, and in which a heat treatment is applied to said plate so that, in the temperature range of said heat treatment, the intermediate layer is plastically deformable and the presence of the selected extrinsic atoms or molecules in the selected base material causes the irreversible formation of micro-bubbles or micro-cavities in the intermediate layer.