Stimulus-Responsive Adhesive Film for Fan-Out WLP Position Stability
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Solution Overview
Problem
During the manufacturing of electronic devices using the fan-out type WLP method, the adhesive film fails to effectively prevent position shifting of electronic components during the sealing process, leading to inaccuracies and potential defects.
Innovation Solution
An adhesive film with a base material layer and two adhesive resin layers, where one layer has a decreased adhesive force upon external stimulus, specifically designed to suppress position shifting by maintaining adequate tack strength values (F2.5 and F30) to prevent floating and outgas-related issues, and includes a heat-expandable component for easy peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an adhesive film is used to temporarily fix electronic components on a support substrate during sealing, then the electronic components can be positioned and sealed in batch, but position shifting of electronic components occurs during the sealing step
Solution Approach 1:
The adhesive resin layer (B) is designed to change its adhesive properties in response to external stimuli (temperature, humidity). During sealing, the adhesive maintains sufficient tack strength to prevent position shifting. After sealing, the external stimulus causes the adhesive force to decrease, enabling easy peeling. This parameter change resolves the contradiction by providing both position stability during sealing and ease of removal afterward.
Solution Approach 2:
The adhesive film transitions from a static adhesive state to a dynamic state where adhesive force can be modulated by external stimuli. The adhesive resin layer (B) dynamically adjusts its adhesive properties: maintaining high adhesion during sealing to prevent position shifting, then reducing adhesion after sealing to enable peeling. This dynamic behavior resolves the contradiction between position stability and ease of removal.
2Manufacturing precision
If the adhesive force of the adhesive resin layer (B) is strong to prevent position shifting, then component placement accuracy is maintained, but peeling from the support substrate becomes difficult
Solution Approach 1:
The adhesive resin layer (B) is designed with stimulus-responsive adhesive properties. During the sealing process, the adhesive maintains strong bonding to ensure accurate component placement. After sealing is complete, application of an external stimulus (temperature or humidity change) causes the adhesive force to decrease significantly, enabling easy peeling from the support substrate. This parameter change resolves the contradiction between strong adhesion for positioning and easy adhesion release for peeling.
Solution Approach 2:
The adhesive film transitions from a static high-adhesion state during sealing to a low-adhesion state after sealing through external stimulus. The adhesive resin layer (B) dynamically adjusts its bonding strength: maintaining strong adhesion during the sealing process to prevent position shifting, then reducing adhesion after sealing to enable easy peeling operations. This dynamic behavior resolves the contradiction between placement accuracy and peeling ease.
3Ease of operation
If the adhesive film is designed with heat-expandable components for easy peeling, then detachment from support substrate is simplified, but the adhesive force may be insufficient to prevent floating during sealing
Solution Approach 1:
The adhesive resin layer (B) is designed with stimulus-responsive adhesive properties that maintain sufficient tack strength during sealing to prevent floating and position shifting. After sealing is complete, application of an external stimulus (temperature or humidity change) causes the adhesive force to decrease, enabling easy peeling. This parameter change resolves the contradiction by providing both adhesive stability during sealing and ease of removal afterward.
Solution Approach 2:
The adhesive film transitions from a static high-adhesion state during sealing to a low-adhesion state after sealing through external stimulus. The adhesive resin layer (B) dynamically adjusts its bonding strength: maintaining strong adhesion during the sealing process to prevent floating and position shifting, then reducing adhesion after sealing to enable easy peeling operations. This dynamic behavior resolves the contradiction between adhesive stability during sealing and peeling ease.
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 adhesive film effectively suppresses position shifting of electronic components during sealing, ensuring accurate placement and easy detachment from the support substrate, thereby enhancing manufacturing precision and efficiency.
Implementation Method 1
the adhesive resin layer (B) includes at least one selected from a gas generating component and a heat-expandable microsphere
Implementation Method 2
an adhesive resin layer (B) provided on a second surface side of the base material layer and in which an adhesive force is decreased by an external stimulus
Data Source
AI summary
An adhesive film includes a base material layer; an adhesive resin layer (A) provided on a first surface side of the base material layer; and an adhesive resin layer (B) provided on a second surface side of the base material layer and in which an adhesive force is decreased by an external stimulus, in which, as measured by method 1, an integrated tacking force value (F2.5) of the adhesive resin layer (B) is 1.0 gf/sec or more at a test speed of 2.5 mm/min and a test temperature of 130° C., and an integrated tacking force value (F30) of the adhesive resin layer (B) is 7.0 gf/sec or more at a test speed of 30 mm/min and a test temperature of 130° C.