Patterned Die Backside Layer for Warpage-Controlled Package Assembly
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Solution Overview
Problem
The use of thick die backside layers with higher thermal expansion coefficients than silicon in integrated circuits leads to die warpage during thermal compression bonding, causing issues like solder bridging and joint opens.
Innovation Solution
Implementing patterned die backside layers with unfilled grooves, support features, and non-uniform interconnect structures to mitigate warpage during assembly, using materials with higher Young's modulus and optimized opening patterns to manage thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thick die backside layers are used to improve heat dissipation and warpage control, then thermal conductivity and warpage control are improved, but die warpage during thermal compression bonding worsens due to CTE mismatch
Solution Approach 1:
The die backside layer is segmented into multiple regions with different thicknesses, creating a non-uniform structure that compensates for thermal expansion differences and reduces warpage during bonding
Solution Approach 2:
Different regions of the die backside layer are assigned different thicknesses to provide localized mechanical support and thermal management, with thicker regions providing additional support where needed
2Temperature
If thick die backside layers are used to improve heat dissipation, then thermal conductivity is improved, but manufacturing precision worsens due to solder bridging and joint opens
Solution Approach 1:
The backside layer is divided into multiple thickness regions that prevent excessive warpage, thereby avoiding solder bridging at die corners and joint opens at die center regions during assembly
Solution Approach 2:
The non-uniform thickness distribution is designed in advance to counteract the expected warpage forces during thermal compression bonding, preventing manufacturing defects before they occur
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
Reduces die warpage and prevents solder bridging and joint opens, improving assembly yield and product performance by enhancing mechanical support and heat dissipation.
Implementation Method 1
Die backside layers, either metallic or composite, may exhibit high thermal conductivities and thus can benefit package heat dissipation
Implementation Method 2
the die backside layers may possess a coefficient of thermal expansion (CTE) that is larger than that of silicon. This CTE mismatch can result in die warpage during TCB
Data Source
AI summary
Microelectronic die package structures formed according to some embodiments may include a substrate and a die having a first side and a second side. The first side of the die is coupled to the substrate, and a die backside layer is on the second side of the die. The die backside layer includes a plurality of unfilled grooves in the die backside layer. Each of the unfilled grooves has an opening at a surface of the die backside layer, opposite the second side of the die, and extends at least partially through the die backside layer.