Wafer Carrier Substrate Demounting via Segmented Bonding
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Solution Overview
Problem
Current methods for debonding ultrathin semiconductor wafers from carriers are slow, prone to wafer breakage, and cause internal device damage due to high thermal and mechanical stresses, limiting throughput and device yield.
Innovation Solution
A method involving a temporary wafer bonding structure where a first substrate is bonded to a second substrate using an intermediate layer with a low bonding interface, allowing for separation by applying a peeling motion with a ring clamp or adhesive film, minimizing mechanical force and stress on the device wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal or chemical debonding processes are used to separate ultrathin wafers from carriers, then the wafer can be released from the carrier, but high thermal and mechanical stresses cause internal device damage and reduce device yield
Solution Approach 1:
The bonding interface is segmented into two distinct regions: a first peripheral region with strong bonding for secure attachment during processing, and a second peripheral region with weak bonding for easy release. This segmentation allows the wafer to be firmly held during fabrication while enabling stress-free separation afterward, eliminating internal device damage caused by uniform strong bonding.
Solution Approach 2:
Different bonding strengths are applied to different regions of the carrier wafer perimeter. The first peripheral region maintains strong bonding properties for secure handling, while the second peripheral region is modified to have weak bonding properties for easy release. This local differentiation of bonding quality enables selective separation without applying stress across the entire wafer structure.
2Productivity
If conventional debonding methods are used, then separation can be achieved, but the process is slow and reduces manufacturing throughput
Solution Approach 1:
The bonding mechanism is extracted and differentiated into two functional regions: one for secure attachment and one for easy release. By removing the uniform bonding characteristic and replacing it with spatially varying bonding strengths, the release process becomes rapid and simple, eliminating the time-consuming thermal or chemical treatments required by conventional methods.
Solution Approach 2:
Instead of using strong uniform bonding that requires complex thermal or chemical processes for release, the invention inverts the approach by using weak bonding in the release region from the outset. This allows spontaneous, rapid separation without energy input, completely reversing the conventional paradigm of strong bonding requiring weak release mechanisms.
3Strength
If strong uniform bonding is used across the entire carrier surface, then secure attachment during processing is achieved, but separation requires high forces that cause wafer breakage
Solution Approach 1:
The bonding interface is divided into strong-bonding regions for secure attachment and weak-bonding regions for easy release. This segmentation allows the wafer to be firmly held during fabrication processes while enabling low-force separation, eliminating wafer breakage caused by uniform strong bonding that requires high release forces.
Solution Approach 2:
Different bonding strengths are localized to different peripheral regions of the carrier. The first peripheral region maintains strong bonding for secure handling during processing, while the second peripheral region is modified to provide weak bonding for gentle release. This local quality differentiation enables secure attachment without requiring high forces for separation.
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
Enables efficient and low-stress separation of ultrathin wafers, reducing the risk of breakage and improving throughput by using a peeling motion to release the wafer from the carrier, maintaining the integrity of the device wafer during processing.
Implementation Method 1
bonded to one another by an intermediate layer with a low bonding interface
Implementation Method 2
separating the first substrate and second substrate by applying a peeling motion
Data Source
Figure 1~2(d)
Figure 3(a)~3(d)
Figure 4(a)~4(d)
AI summary
New demounting methods and apparatuses for separating temporarily, permanently, or semi-permanently bonded substrates and articles formed from those methods and apparatuses are provided. The methods comprise demounting a device wafer from a carrier wafer or substrate that have only been strongly bonded at their outer perimeters. The edge bonds are chemically, mechanically, acoustically, or thermally softened, dissolved, or disrupted to allow the wafers to be easily separated with very low forces and at or near room temperature at the appropriate stage in the fabrication process. A clamp for facilitating separation of the bonded substrates is also provided.