Heat Spender Bonding via Thermal Interface and Capillary Adhesive
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Solution Overview
Problem
Existing semiconductor device assemblies require careful process control to achieve the desired interface between the heat sink and the die, as well as the heat sink and the mold compound, which can be challenging due to the need for precise bonding and adhesive attachment.
Innovation Solution
The method involves decoupling the control of heat sink to die bonding from the adhesive attachment to the mold compound by applying a thermal interface material to the die surface and then attaching the heat spreader, followed by dispensing an adhesive through vent openings in the heat spreader to fill the gap between the heat spreader and the mold compound, allowing for independent control of the interface and adhesive application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive material is applied to the mold compound surface before heat spreader attachment, then the heat spreader can be bonded to both the die and mold compound, but the interface control between heat spreader and die becomes difficult to achieve precisely
Solution Approach 1:
The patent segments the bonding process into two independent stages: first bonding the heat spreader to the die using thermal interface material, then separately bonding the heat spreader periphery to the mold compound using adhesive material applied through vent openings. This segmentation allows independent optimization and control of each bonding interface, resolving the contradiction between achieving reliable bonding and maintaining precise interface control.
Solution Approach 2:
The patent performs preliminary action by first attaching the heat spreader to the die before applying adhesive to the mold compound. This sequence ensures that the critical heat spreader-die interface is established with precise control first, and then the secondary heat spreader-mold compound interface is formed separately, allowing each interface to be optimized independently.
2Strength
If adhesive material is applied around the entire heat spreader periphery, then the heat spreader is securely attached to the mold compound, but the adhesive may interfere with the thermal interface between heat spreader and die
Solution Approach 1:
The patent extracts the adhesive application from the thermal interface area by applying adhesive only through vent openings located away from the die-heat spreader interface. This ensures that adhesive material is confined to the periphery and does not contaminate or interfere with the thermal interface between the heat spreader and die, maintaining both attachment strength and thermal interface reliability.
Solution Approach 2:
The vent openings serve as intermediaries that allow adhesive material to be delivered to the heat spreader periphery without directly contacting the thermal interface area. This intermediary mechanism enables separate control of the adhesive bonding process while protecting the thermal interface from contamination.
3Ease of manufacture
If the heat spreader is attached directly to the mold compound without separate adhesive application, then the process is simpler, but the gap filling between heat spreader and mold compound is insufficient
Solution Approach 1:
The patent employs capillary action to enable the adhesive material to automatically flow and fill the gap between the heat spreader and mold compound through the vent openings. This self-service mechanism eliminates the need for complex external application equipment or manual intervention, maintaining process simplicity while achieving precise gap filling through the natural capillary flow of the adhesive material.
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 enables tighter control over the interface between the heat spreader and the die, improving manufacturing precision and thermal performance while ensuring reliable attachment of the heat spreader to the semiconductor device assembly.
Implementation Method 1
a thermal interface material to the die surface and then attaching the heat spreader
Implementation Method 2
dispensing an adhesive through vent openings in the heat spreader to fill the gap between the heat spreader and the mold compound
Data Source
AI summary
A method includes providing an integrated circuit (IC) die assembly that includes a substrate and an IC die mounted on a portion of a major surface of the substrate, dispensing an interface material on the IC die, positioning a portion of a heat spreader in contact with the interface material, and dispensing an adhesive between one side of the heat spreader facing the IC die assembly and exposed portions of a major surface of an encapsulant on the substrate.