Wafer Reinforcement Ring Bonding for High-Temperature SiC Processing
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Solution Overview
Problem
Existing methods for thickening the outer periphery of wafers, particularly those made of hard materials like SiC, face challenges in grinding and are not suitable for high-temperature treatment processes due to adhesive material limitations.
Innovation Solution
A method involving bonding a ring-shaped frame to the wafer's outer peripheral portion using atom irradiation to form an amorphous layer, which enhances bonding strength and allows for high-temperature processing without intermediate materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a reinforcement ring is fastened to a semiconductor substrate using an adhesive member, then the strength of the semiconductor substrate is kept and warping/cracking is prevented, but the adhesive member may not be resistant to high temperature environment
Solution Approach 1:
An amorphous layer is introduced as an intermediary between the semiconductor substrate and the reinforcement ring. This amorphous layer is formed by irradiating the bonding surfaces with ions (such as Ga ions) to create a reactive surface that enables direct bonding without requiring adhesive members. The amorphous layer acts as a mediator that provides both bonding strength and high-temperature resistance, resolving the contradiction between needing strong bonding and withstanding high temperatures.
Solution Approach 2:
The conventional mechanical bonding method using adhesive members is replaced with a physical-chemical bonding method. By irradiating the bonding surfaces with ions to form an amorphous layer, the bonding is achieved through atomic-level interactions rather than mechanical adhesion. This substitution eliminates the temperature limitation imposed by adhesive materials while maintaining strong bonding between the substrate and reinforcement ring.
2Strength
If the back surface of a device region is thinned by grinding to thicken the outer periphery, then the wafer strength is improved and warping/cracking is prevented, but it is technically difficult to grind only a back surface of a device region made of hard material such as SiC
Solution Approach 1:
The wafer structure is segmented into different regions with different thicknesses: the device region maintains its original thin thickness while the outer peripheral portion is thickened by bonding a reinforcement ring. This segmentation allows the outer periphery to provide mechanical strength and prevent warping/cracking, while the device region remains intact for proper device operation. The reinforcement ring acts as a separate structural element that compensates for the thinness of the device region.
Solution Approach 2:
Instead of removing material from the back surface of the device region through grinding (the conventional approach), the invention adds material to the outer peripheral portion by bonding a reinforcement ring. This inverted approach achieves the same goal of thickening the outer periphery to prevent warping and cracking, but avoids the technical difficulties of selective grinding of hard materials like SiC.
3Strength
If adhesive members are used to bond the reinforcement ring to the wafer, then bonding is achieved, but the adhesive member may not be resistant to high temperature treatment process
Solution Approach 1:
The amorphous layer formed by ion irradiation serves as an intermediary bonding interface between the semiconductor substrate and the reinforcement ring. This amorphous layer creates a direct atomic-level bond that is resistant to high temperatures, eliminating the need for temperature-sensitive adhesive members. The intermediary layer enables the system to withstand high-temperature treatment processes while maintaining strong bonding.
Solution Approach 2:
The bonding mechanism is changed from chemical adhesion (using adhesive members) to physical-chemical bonding through amorphous layer formation. By changing the bonding parameter from organic-based adhesion to inorganic amorphous layer bonding, the system gains high-temperature resistance while maintaining adequate bonding strength for the reinforcement application.
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 effectively prevents warping and cracking of wafers during processing, enabling their use in high-temperature treatments and reducing manufacturing costs by eliminating the need for complex grinding processes.
Implementation Method 1
activating a surface layer of the outer peripheral portion of the wafer and a surface layer of the frame by atom irradiation
Implementation Method 2
sandwiching the wafer and the frame between the stage and the chuck part and pressure-bonding the activated surface layers of the wafer and the frame using the pressure-bonding mechanism
Data Source
AI summary
According to the present disclosure, A method for manufacturing a semiconductor apparatus bonds a ring-shaped frame to an outer peripheral portion of a wafer, and comprises the steps of installing one of the wafer and the frame on a stage, holding another of the wafer and the frame in a chuck part in a pressure-bonding mechanism, activating a surface layer of the outer peripheral portion of the wafer and a surface layer of the frame by atom irradiation, and sandwiching the wafer and the frame between the stage and the chuck part and pressure-bonding the activated surface layers of the wafer and the frame using the pressure-bonding mechanism. An amorphous layer is formed on a bonding interface between the wafer and the frame pressure-bonded to each other.