Backside Contact Pedestal for Semiconductor Package Thermal Management
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Solution Overview
Problem
Existing semiconductor packaging techniques face challenges in achieving high density due to the need for large heat transfer devices and inability to accommodate die of varying thicknesses, especially in designs requiring backside electrical and thermal contacts, which often require resource-intensive processing steps and compromise device density.
Innovation Solution
The method involves attaching conductive pedestals to the backside of die prior to encapsulation, using a conductive adhesive, and exposing them through a grinding or polishing process to provide effective thermal and electrical access without increasing package size, allowing for die of varying thicknesses to be accommodated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If large heat spreader or heat sink is provided to enhance thermal transfer from embedded die, then thermal transfer capability is improved, but package size increases and device density decreases
Solution Approach 1:
The patent transitions from planar heat spreading (2D) to vertical heat conduction (1D) by attaching heat transfer elements directly to the backside of the die. This dimensional change allows efficient thermal management without increasing the package footprint, as heat is conducted vertically through the thickness of the package rather than requiring large lateral heat spreaders.
Solution Approach 2:
The heat transfer elements are attached to the backside of the die before the die is mounted in the package. This preliminary action allows the thermal path to be established in advance, enabling efficient heat conduction from the die backside without requiring additional space in the final package configuration.
2Ease of operation
If packaging techniques such as redistributed chip packaging (RCP) are used, then electrical contact to both sides of die is enabled, but die of varying thicknesses cannot be accommodated without damaging the device die or involving significant additional processing steps
Solution Approach 1:
The patent introduces a compliant underfill material as an intermediary between the die and the package substrate. This underfill accommodates thickness variations in the die by providing a compliant interface that can deform to match different die heights, preventing damage during the RCP process while maintaining electrical contact integrity.
Solution Approach 2:
The patent changes the mechanical properties of the interface materials (using compliant underfill and flexible adhesives) to allow accommodation of varying die thicknesses. This parameter change in material compliance enables the packaging process to handle die with different thicknesses without requiring precise thickness control or additional processing steps.
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 efficient thermal and electrical access to die backside contacts while conserving package space, simplifying processing and maintaining device density, and allows for the use of die with varying thicknesses in the same package.
Implementation Method 1
The conductive pedestals are made of electrically or thermally conductive material and coupled to the device die contact using an electrically and/or thermally conductive adhesive
Data Source
AI summary
A method and apparatus for forming a backside contact, electrical and/or thermal, for die encapsulated in a semiconductor device package are provided. Die of varying thicknesses can be accommodated within the semiconductor device package. Embodiments of the present invention provide a conductive pedestal coupled to a backside contact of a die, where the coupling is performed prior to encapsulating the die within the package. In addition, conductive pedestals coupled to varying die within a semiconductor device package are of such a thickness that each conductive pedestal can be exposed on the back side of the package without exposing or damaging the backside of any encapsulated die. Embodiments of the present invention provide for the conductive pedestals being made of electrically or thermally conductive material and coupled to the device die contact using an electrically and/or thermally conductive adhesive.