Substrate Thinning Liquid Seal Vacuum Leakage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in semiconductor device manufacturing is the warpage and damage caused by varying coefficients of thermal expansion during the fabrication process, leading to issues like vacuum leakage, unacceptable total thickness variation, and yield loss due to grinding processes.
Innovation Solution
A method and system for thinning semiconductor devices using a liquid seal to manage warpage and secure the substrate during grinding, involving a chuck with a liquid supply unit to seal gaps and maintain uniform vacuum suction, preventing over-grinding and enhancing surface uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a conventional grinding process is used to thin the semiconductor device, then the thickness is reduced, but vacuum leakage occurs at the edge due to warpage
Solution Approach 1:
A liquid sealant is introduced as an intermediary substance between the substrate edge and the chuck surface to fill gaps caused by warpage. The liquid sealant creates a reliable vacuum seal even when the substrate is warped, preventing vacuum leakage during the grinding process.
Solution Approach 2:
The system dynamically adjusts the vacuum pressure parameters and liquid sealant flow rate to maintain effective sealing. By changing these parameters in response to detected warpage conditions, the system maintains reliable vacuum sealing throughout the thinning process.
2Length of moving object
If the final thickness of the semiconductor device is reduced, then the device size is smaller, but damage caused by the grinding process increases
Solution Approach 1:
A feedback control system continuously monitors the substrate thickness and warpage during grinding. Based on this real-time information, the system automatically adjusts grinding parameters such as wheel pressure, rotation speed, and feed rate to prevent over-grinding and structural damage while achieving the target thickness.
Solution Approach 2:
The system applies partial grinding actions with multiple passes rather than removing all material in a single aggressive pass. This approach allows for careful removal of material while maintaining structural integrity, with each pass removing only a controlled amount and allowing inspection between passes.
3Length of moving object
If the structure thickness is reduced, then the device is smaller, but the structure becomes warped at its periphery and easily cracked during grinding
Solution Approach 1:
The liquid sealant acts as a counterbalancing force at the substrate periphery, providing support that counteracts the warpage forces. This prevents the edges from warping during grinding and reduces the risk of cracking, maintaining surface uniformity even in thin structures.
Solution Approach 2:
The liquid sealant is applied beforehand to create a cushioning effect at the substrate-chuck interface. This cushioning layer prevents direct mechanical contact that could cause cracking in thin, warped regions, and provides gradual support as the grinding process progresses.
4Length of moving object
If a grinding process is performed to reduce thickness, then the device is thinned, but over-grinding may occur and cause damage leading to yield loss
Solution Approach 1:
A feedback control system with real-time thickness monitoring prevents over-grinding by automatically adjusting or stopping the grinding process when the target thickness is approached. This ensures consistent dimensional control and prevents damage that would reduce yield.
Solution Approach 2:
The grinding process is divided into multiple partial removal stages rather than attempting to remove all excess material in one aggressive pass. This allows for careful approach to the target thickness with inspection opportunities, preventing over-grinding and associated yield loss.
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 approach effectively reduces warpage-related vacuum leakage and achieves precise thinning with minimal total thickness variation, improving the yield and quality of semiconductor devices by securely holding the substrate during the thinning process.
Implementation Method 1
a first liquid supply unit adapted to deliver a liquid to cover a sidewall of the substrate
Implementation Method 2
a chuck adapted to secure the substrate placed thereon
Data Source
AI summary
A system for thinning a substrate includes a chuck and a first liquid supply unit. The chuck includes a base portion and a frame portion disposed on the base portion, where the substrate is configured to be placed on a carrying surface of the chuck. The first liquid supply unit extends along sidewalls the frame portion and the base portion, an outlet of the first liquid supply unit is disposed next to the carrying surface of the chuck, the first liquid supply unit delivers a first liquid from a bottom of the chuck to the outlet, and the first liquid discharges from the outlet to cover a sidewall of the substrate.