Flexible IC Adhesion Control via Selective Laser Treatment
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Solution Overview
Problem
Current wafer integration techniques require additional handling steps and incur costs due to the need for transferring flexible plastic substrates from glass carriers to adhesive films, with challenges in controlling adhesion strength for secure shipping and handling while allowing for easy removal of integrated circuits (ICs).
Innovation Solution
A process using non-uniform electromagnetic radiation treatment to selectively change the adhesion strength between flexible substrates and carriers at specific locations, allowing for direct transfer of ICs from the carrier to contact pads without an intermediate adhesive film, utilizing focused or defocused radiation to create regions of varying adhesion for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electromagnetic radiation treatment is applied to reduce adhesion between flexible substrate and carrier, then IC removal becomes easier, but adhesion strength becomes insufficient for secure shipping and handling
Solution Approach 1:
The patent applies electromagnetic radiation treatment selectively at specific locations (e.g., corners or edges) of the flexible substrate rather than uniformly across the entire substrate. This creates localized regions with modified adhesion properties, allowing the IC to be easily removed from specific pickup points while maintaining strong adhesion in other areas for secure handling and shipping.
2Reliability
If uniform adhesion strength is maintained across the entire flexible substrate, then shipping security is improved, but additional handling steps and intermediate adhesive films are required for IC removal
Solution Approach 1:
The patent segments the adhesion strength across the flexible substrate by applying electromagnetic radiation treatment to specific locations only. This creates distinct zones with different adhesion characteristics: treated zones allow easy IC removal while untreated zones maintain strong adhesion for shipping security, thereby eliminating the need for intermediate adhesive films and reducing handling steps.
3Ease of manufacture
If electromagnetic radiation is applied at fixed discrete intervals, then processing is simplified, but uniform and balanced release control becomes difficult with narrow process window
Solution Approach 1:
The patent modifies the electromagnetic radiation treatment parameters by applying radiation at specific locations with controlled duration and intensity. This allows precise control over the degree of adhesion modification at each treated location, enabling balanced release control while maintaining processing simplicity through targeted application rather than uniform treatment.
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 ensures the positional integrity of diced flexible ICs during handling and shipment, eliminating intermediate transfer steps and related costs by allowing direct picking from the carrier, while maintaining sufficient adhesion for storage and handling.
Implementation Method 1
changing the adhesion force between the flexible substrate and the carrier at one or more selected locations by non-uniform treatment of the interface between the flexible substrate and the carrier with an electromagnetic radiation source
Implementation Method 2
The mechanism will depend on whether the electromagnetic radiation source causes predominantly a photonic ablation (through absorption) or a thermal process
Implementation Method 3
The mechanism will depend on whether the electromagnetic radiation source causes predominantly a photonic ablation (through absorption) or a thermal process (e.g. heat-release)
Data Source
AI summary
One exemplary aspect relates to a process and apparatus for selectively changing adhesion strength between a flexible substrate and a carrier at specific locations to facilitate shipping and subsequent removal of the flexible substrate from the carrier. The process includes providing a flexible substrate comprising a plurality of integrated circuits thereon providing a carrier for the flexible substrate and adhering the flexible substrate to the carrier by creating an interface between the flexible substrate and the carrier. The process further includes changing the adhesion force between the flexible substrate and the carrier at selected locations by non-uniform treatment of the interface between the flexible substrate and the carrier with an electromagnetic radiation source (e.g. a laser, flashlamp, high powered LED, an infrared radiation source or the like) so as to decrease or increase the adhesion force between a portion of the flexible substrate and the carrier at the selected location.