Composite Carrier Laser De-Bonding with Absorption Layer Reuse
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Solution Overview
Problem
Current methods for de-bonding permanently bonded wafers in integrated circuit packaging are inefficient, as they require destructive processes like chemical mechanical polish, grinding, or etching, which can damage the carrier and are time-consuming, limiting reuse and increasing costs.
Innovation Solution
A composite carrier structure with a transparent base carrier and an absorption layer, such as titanium nitride, is used, where a laser beam with specific wavelengths and power density is applied to ablate the absorption layer, allowing for non-destructive de-bonding without damaging the base carrier, enabling its reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If destructive processes like chemical mechanical polish, grinding, or etching are used to de-bond permanently bonded wafers, then the bonding can be broken, but the carrier is damaged and the process is time-consuming
Solution Approach 1:
The carrier is segmented into multiple layers with distinct functions: a transparent base carrier layer and an absorption layer. This segmentation allows the absorption layer to be selectively removed by laser ablation while preserving the base carrier, enabling fast de-bonding without damaging the reusable carrier.
Solution Approach 2:
An absorption layer is introduced as an intermediary between the base carrier and the package component. This intermediary layer absorbs laser energy and can be selectively ablated, serving as a sacrificial element that enables controlled de-bonding without transmitting harmful energy to the base carrier or package component.
2Ease of manufacture
If destructive processes are used to remove the carrier, then the wafer can be de-bonded, but the process damages the carrier and increases costs
Solution Approach 1:
The absorption layer is pre-applied to the base carrier before bonding to the package component. This preliminary action creates a built-in de-bonding mechanism that enables rapid, non-destructive separation later, eliminating the need for time-consuming destructive removal processes and allowing carrier reuse.
3Device complexity
If a single-layer carrier is used, then the structure is simple, but the de-bonding process must be destructive and time-consuming
Solution Approach 1:
The carrier is constructed as a composite structure combining a transparent base carrier material with an absorption layer having different optical properties. This composite structure enables selective laser ablation of the absorption layer while preserving the base carrier, achieving fast de-bonding without increasing overall device complexity.
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
The laser de-bonding process is faster, more cost-effective, and improves uniformity by limiting the de-bonding interface to the absorption layer, allowing for efficient separation of the base carrier from the package component without damaging it, thus reducing costs and improving throughput.
Implementation Method 1
an absorption layer over the base carrier, wherein the absorption layer is between the base carrier and the package component; projecting a laser beam onto the composite carrier, wherein the laser beam penetrates through the base carrier to ablate the absorption layer
Implementation Method 2
a base carrier, wherein the base carrier is transparent to the laser beam; projecting a laser beam onto the composite carrier, wherein the laser beam penetrates through the base carrier to ablate the absorption layer
Implementation Method 3
projecting a laser beam onto the composite carrier, wherein the laser beam penetrates through the base carrier to ablate the absorption layer; separating the base carrier from the package component
Data Source
AI summary
A method includes bonding a package component to a composite carrier. The composite carrier includes a base carrier and an absorption layer, and the absorption layer is between the base carrier and the package component. A laser beam is projected onto the composite carrier. The laser beam penetrates through the base carrier to ablate the absorption layer. The base carrier may then be separated from the package component.