Mold Release Film for Semiconductor Packaging
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Solution Overview
Problem
Existing mold release films for semiconductor elements are inadequate in releasability against cured resin, prone to contamination, and have insufficient peeling properties, leading to defects such as discoloration and adhesive residue during the production of semiconductor elements with exposed surfaces.
Innovation Solution
A film comprising a substrate with an adhesive layer made from a reaction-cured product of an acrylic polymer and a polyfunctional isocyanate compound, specifically designed to have a storage elastic modulus of 10-100 MPa at 180°C, with a composition that balances hydroxy and carboxy groups and isocyanate ratios to ensure excellent releasability and low migration properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the clamping pressure of the mold is increased to strongly press the mold to the exposed portion, then leakage of curable resin is reduced, but the exposed portion is likely to be dented or damaged
Solution Approach 1:
A mold release film is introduced as an intermediary layer between the mold and the exposed portion of the semiconductor chip. This film prevents direct contact while maintaining adequate clamping pressure, thereby preventing resin leakage without causing damage to the exposed portion. The film acts as a buffer that distributes the pressure uniformly.
Solution Approach 2:
The invention uses a thin film structure with specific mechanical properties (storage elastic modulus of 10-1000 MPa at 180°C) that allows it to deform under pressure and conform to the mold surface while protecting the underlying exposed portion. The film's flexibility enables it to absorb clamping pressure without transmitting excessive stress to the semiconductor chip.
2Strength
If the clamping pressure is reduced to prevent damage to the exposed portion, then the exposed portion integrity is maintained, but resin leakage increases
Solution Approach 1:
The mold release film serves as a mediator that enables effective resin leakage prevention even at reduced clamping pressures. By placing the film between the mold and the exposed portion, the system can achieve adequate sealing without applying excessive force that would damage the chip.
Solution Approach 2:
The invention changes the physical parameters of the interface between mold and exposed portion by introducing a film with specific mechanical properties. The storage elastic modulus range (10-1000 MPa at 180°C) is carefully selected to optimize both protection and leakage prevention functions under various clamping pressure conditions.
3Object-affected harmful factors
If conventional mold release films are used, then resin leakage is reduced, but releasability against cured resin and peeling properties are insufficient
Solution Approach 1:
The invention optimizes the storage elastic modulus parameter of the mold release film within the range of 10-1000 MPa at 180°C. This parameter control ensures that the film maintains adequate rigidity to prevent resin leakage while remaining sufficiently compliant to allow easy peeling after curing. The specific modulus range balances the conflicting requirements of leakage prevention and peeling ease.
Solution Approach 2:
The mold release film is constructed as a composite structure with a substrate and an auxiliary layer having different mechanical properties. The auxiliary layer has a compression elastic modulus lower than the substrate film, creating a gradient structure that optimizes both the leakage prevention capability (through the stiffer substrate) and the peeling property (through the more compliant auxiliary layer).
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 film provides superior releasability and peeling properties, reducing contamination and adhesive residue, and is suitable for producing semiconductor elements with exposed surfaces, enhancing productivity and surface quality.
Implementation Method 1
a film comprising a substrate and an adhesive layer provided on one surface of the substrate... excellent releasability and peeling properties, reducing contamination and adhesive residue
Implementation Method 2
the storage elastic modulus at 180° C. of the substrate is from 10 to 100 MPa... providing releasability from a molded article
Data Source
AI summary
To provide a film which is excellent in releasing property with respect to a resin sealed portion and excellent in low migration property and peeling property with respect to a semiconductor chip, a source electrode or a sealing glass and which is suitable as a mold release film for producing a semiconductor element having a part of the surface of a semiconductor chip, source electrode or sealing glass exposed. A film 1 which comprises a substrate 3 and an adhesive layer 5, wherein the storage elastic modulus at 180° C. of the substrate 3 is from 10 to 100 MPa, and the adhesive layer 5 is a reaction cured product of a composition for adhesive layer comprising a specific acrylic polymer and a polyfunctional isocyanate compound, wherein the number of moles MOH of hydroxy groups and the number of moles MCOOH of carboxy groups, derived from the acrylic polymer, and the number of moles MNCO of isocyanate groups derived from the polyfunctional isocyanate compound, satisfy a specific relation, and which is suitable as a mold release film for producing a semiconductor element.