Wafer Bonding Adhesive Placement Recess
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Thinned semiconductor device wafers with a thickness of 50 μm or smaller are difficult to handle due to chipping and reduced rigidity, and the deposition of adhesive on the device surface can lead to device failures, especially in wafers with MEMS devices and optical devices, as it is challenging to remove adhesive from minute concavities and convexities and high-temperature processes can cause adhesive-related defects.
Innovation Solution
A method involving a carrier wafer with a recessed area for adhesive placement, ensuring the adhesive is applied only to the outer circumferential region, preventing its deposition on the device region, and subsequent thinning and peeling steps to maintain wafer integrity and prevent adhesive-related failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive is applied to the device wafer surface for bonding to carrier wafer, then wafer bonding is achieved, but adhesive deposits on device region causing device failures
Solution Approach 1:
The wafer surface is divided into device region and excessive outer circumferential region. Adhesive is applied only to the excessive outer circumferential region, segmenting the bonding area from the device area to prevent adhesive contamination of devices while maintaining bonding functionality.
Solution Approach 2:
Different regions of the wafer are given different properties: the excessive outer circumferential region receives adhesive for bonding, while the device region is kept free of adhesive. This local differentiation ensures bonding occurs only where needed without contaminating sensitive device areas.
2Manufacturing precision
If wafer is thinned to 50 μm or smaller to improve device performance, then device functionality is enhanced, but handling difficulty increases due to chipping and reduced rigidity
Solution Approach 1:
The thinned device wafer is bonded to a carrier wafer, merging the two structures into a composite assembly. The carrier wafer provides mechanical support and rigidity to the thin device wafer, enabling safe handling and subsequent processing without compromising the thinned wafer's precision.
Solution Approach 2:
The carrier wafer acts as an intermediary structure that supports the thinned device wafer during handling and processing. This mediator provides the necessary mechanical strength and rigidity that the thin device wafer lacks, while allowing the device wafer to maintain its precise thinned dimensions.
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
Prevents device failures by ensuring the adhesive does not contact the device surface during processing, maintaining wafer rigidity, and allowing for successful high-temperature processes without adhesive-induced defects, thereby enhancing handling and processing reliability.
Implementation Method 1
an adhesive placing step of placing an adhesive in said recess so as to project from the front surface of said carrier wafer; after performing said adhesive placing step, a wafer bonding step of bonding the front surface of said carrier wafer and the front surface of said device wafer to each other with said adhesive
Implementation Method 2
a thinning step of thinning said device wafer to a predetermined thickness by grinding or polishing a rear surface of said device wafer
Data Source
AI summary
A method of processing a device wafer includes the carrier wafer preparing step of preparing a carrier wafer including an excessive carrier region on a surface thereof which is disposed in a position corresponding to an excessive outer circumferential region on a surface of the device wafer, the recess forming step of forming a recess in the excessive carrier region the carrier wafer, after the recess forming step, the adhesive placing step of placing an adhesive in the recess so as to project from the surface of the carrier wafer, after the adhesive placing step, the wafer bonding step of bonding the surface of the carrier wafer and the surface of the device wafer to each other, thereby securing the device wafer to the carrier wafer with the adhesive, and after the wafer bonding step, the thinning step of thinning the device wafer to a predetermined thickness by grinding or polishing a reverse side of the device wafer.