Compression Molding IC Die Packaging Using Reinforced Adhesive Film
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Solution Overview
Problem
Conventional chips-first packaging techniques face issues with temperature-sensitive thermal release tapes causing IC die drift and complexity, along with high costs and reliability concerns due to the use of costly and short-shelf-life liquid compounds.
Innovation Solution
The method employs a flexible structurally reinforced single-sided adhesive film and granular epoxy resin for compression molding, eliminating the need for a support substrate and thermal release tape, thereby simplifying the process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If thermal release tape is used to facilitate release of cured encapsulated structure from support substrate, then release is enabled, but adhesion properties are drastically reduced at elevated temperatures causing IC dies to drift from desired location
Solution Approach 1:
The patent removes the thermal release tape from the packaging process entirely. Instead of using thermal release tape to facilitate release, the invention uses a support substrate with a release layer that allows release without requiring thermal release tape, thereby eliminating the adhesion loss and IC die drift problem at elevated temperatures during compression molding
Solution Approach 2:
The patent introduces a release layer as an intermediary between the support substrate and the encapsulated structure. This release layer (such as a fluoropolymer coating) provides the necessary release properties without the temperature-sensitive adhesion characteristics of thermal release tape, enabling release while maintaining IC die placement accuracy
2Reliability
If conventional chips-first packaging technique with support substrate and thermal release tape is used, then IC dies can be mounted and encapsulated, but the process becomes complex and costly with multiple material layers and processing steps
Solution Approach 1:
The patent eliminates the thermal release tape layer and the associated adhesion control steps from the packaging process. By removing this problematic intermediate layer, the process complexity is reduced while maintaining reliable encapsulation through the use of a simplified support substrate with an integrated release layer
Solution Approach 2:
The patent combines the support substrate and release layer into an integrated structure, where the release layer is applied directly to the support substrate. This merging eliminates the need for separate thermal release tape application and removal steps, simplifying the overall packaging process while maintaining reliability
3Reliability
If liquid epoxy resin is used as molding material, then encapsulation can be achieved, but the material has short shelf life and requires costly storage and handling
Solution Approach 1:
The patent changes the physical state of the molding material from liquid to granular or preformed solid form. This parameter change allows the material to have a long shelf life and be stored at ambient temperatures, while still achieving reliable encapsulation through compression molding that densifies the granular material or consolidates the preformed structure
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 approach provides better control over IC die placement, reduces production complexity and time, and lowers manufacturing costs while ensuring high reliability by using a low-cost, long-shelf-life granular molding compound and eliminating the need for complex thermal release tape adhesion.
Implementation Method 1
The IC dies and the granular epoxy compound within the mold cavity undergo compression molding to form a molded encapsulant layer over the IC dies
Implementation Method 2
a mold frame and adhesive material are attached to a support substrate to form a mold cavity
Data Source
AI summary
A structure (46) for holding an integrated circuit (IC) die (50) during packing includes a flexible structurally reinforced silicone adhesive film (22) and a mold frame (44). The mold frame (44) adheres to an adhesive side (38) of the film (22). A method (20) of packaging the IC die (50) includes placing the IC die (50) on the adhesive film (22) with its active surface (52) and bond pads (54) in contact with an adhesive side (38) of the film (22). A molding compound (58) is dispensed over the IC die, and the IC die (50) is encapsulated using compression molding to form a compression molded encapsulant layer (70). IC die (50) is subsequently released from the film (22) as a panel (72) of IC dies (50).