Patterned Bonding Layer for Thinned Wafer Support and Dicing
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Solution Overview
Problem
Thinned semiconductor wafers are prone to bowing and warping during processing steps like CMP and ion implantation, and existing temporary bonding/debonding technologies are complex and costly.
Innovation Solution
A method involving a patterned bonding layer formed on the scribe line region of the device wafer, allowing a handle wafer to be bonded and then diced simultaneously, eliminating the need for redundant debonding steps and reducing processing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wafer thinning is performed on thinned wafers, then the semiconductor device can be fabricated, but the wafer becomes frangible and vulnerable to bowing and warping during subsequent processing steps
Solution Approach 1:
A carrier wafer is introduced as an intermediary substrate to support the thinned device wafer during processing. The carrier wafer provides mechanical strength and structural stability to the fragile thinned wafer, preventing bowing and warping during subsequent steps such as CMP, etching, and ion implantation.
Solution Approach 2:
The bonding layer is patterned into discrete regions aligned with scribe lines, separating the bonding function from the device active areas. This segmentation allows the bonding layer to be removed during dicing without affecting the device structures, enabling easy separation of the device wafer from the carrier wafer.
2Reliability
If temporary bonding/debonding technology is used to support thinned wafers, then wafer stability is improved, but the process becomes complex and costly
Solution Approach 1:
The bonding layer is selectively removed by dicing along the scribe lines, extracting the bonding function only where needed for separation. This eliminates the need for a separate debonding step, simplifying the overall process while maintaining wafer stability during processing.
Solution Approach 2:
The dicing process is merged with the bonding layer removal step. By aligning the bonding layer with the scribe lines, a single dicing operation simultaneously separates the device wafer from the carrier wafer and removes the bonding layer, reducing the number of process steps.
3Productivity
If a patterned bonding layer is used to bond the handle wafer, then the dicing process can remove the bonding layer simultaneously, but additional patterning steps are required
Solution Approach 1:
The scribe lines serve multiple functions: they define the dicing paths for separating individual devices and simultaneously define the pattern for the bonding layer. This multi-functionality eliminates the need for separate patterning steps, as the bonding layer pattern is derived from the existing scribe line geometry.
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 simplifies the semiconductor device fabrication process, reduces costs, and prevents wafer damage by allowing direct separation of dices from the handle wafer without additional debonding, enhancing processing efficiency.
Implementation Method 1
performing a photo-resist development process to remove a portion of the photo-resist layer
Implementation Method 2
a handle wafer is bonded to the device wafer by the patterned bonding layer
Implementation Method 3
the dicing process is a laser dicing process
Implementation Method 4
the dicing process is a saw-dicing process
Implementation Method 5
wafer thinning steps are carried out on the backside of the device wafer
Data Source
AI summary
A method for fabricating a semiconductor device, wherein the method comprises steps as follows: Firstly, a device wafer is provided and a patterned bonding layer is then formed within a scribe line region of the device wafer. Subsequently a handle wafer is bonded to the device wafer by the patterned bonding layer. Next, a dicing process is performed along the scribe line region in order to divide the device wafer into a plurality of dices and remove the patterned bonding layer simultaneously, whereby the divided dices can be separated from the handle wafer.