Die-to-Die First Bond for Semiconductor Package Thermal Conductivity
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Solution Overview
Problem
Conventional semiconductor packaging methods face limitations in efficiently bonding semiconductor die to interposers, leading to suboptimal thermal conductivity, mechanical stability, and electrical connectivity, particularly in large panel formats and stacked die configurations.
Innovation Solution
A method and system for a semiconductor device package with a die-to-die first bond, involving bonding semiconductor die to an interposer die using underfill materials and mold encapsulation, with micro-bumps for electrical contact, and thermal compression or mass reflow processes for bonding, allowing for flexible assembly and improved connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional semiconductor packaging methods are used, then the bonding process is simpler, but thermal conductivity and mechanical stability deteriorate
Solution Approach 1:
The bonding process is divided into two distinct stages: first bonding semiconductor die to each other (die-to-die bonding), then bonding the assembled die stack to the interposer (die-to-interposer bonding). This segmentation allows optimization of each bonding stage independently, enabling the use of advanced bonding techniques like Cu-Cu diffusion bonding for die-to-die connections to achieve superior thermal conductivity, while maintaining manageable process complexity through systematic organization of steps.
Solution Approach 2:
The semiconductor die are bonded to each other in advance before being mounted to the interposer substrate. This preliminary die-to-die bonding creates a pre-assembled die stack with optimized thermal pathways established early in the process, ensuring high thermal conductivity is achieved before the final interposer bonding step.
2Reliability
If conventional packaging methods are used, then the manufacturing process is faster, but electrical connectivity and mechanical stability worsen
Solution Approach 1:
The manufacturing process is segmented into parallel tracks: die-to-die bonding operations can be performed on multiple die simultaneously, and these can be prepared in advance while other die are being processed. This segmentation enables overlapping of process steps, improving electrical connectivity through optimized bonding sequences without proportionally increasing overall manufacturing cycle time.
Solution Approach 2:
Die-to-die bonding is performed as a preliminary step before final interposer attachment. This allows electrical connections between die to be established and verified early, ensuring high reliability of electrical connectivity while enabling subsequent steps to proceed in parallel, thereby maintaining manufacturing efficiency.
3Temperature
If die-to-die first bond method is used, then thermal conductivity improves, but device complexity increases
Solution Approach 1:
The assembly process is segmented into modular stages: die preparation, die-to-die bonding, underfill application, and interposer bonding. Each stage is independently optimized and can be performed by specialized equipment, managing the complexity of achieving superior heat dissipation through systematic breakdown of the overall process into manageable, repeatable modules.
Solution Approach 2:
An underfill material is introduced as an intermediary substance between the die stack and interposer during bonding. This underfill layer facilitates thermal management by providing additional thermal pathways, while also simplifying the bonding process by acting as a compliant interface that accommodates thermal expansion differences, thereby managing process complexity while enhancing heat dissipation.
4Reliability
If stacked die configurations are used, then electrical connectivity improves, but mechanical stability worsens
Solution Approach 1:
An underfill material is applied as an intermediary between the stacked die and the interposer substrate. This underfill acts as a mechanical cushion and stress-distributing layer that maintains the structural integrity of the stacked die configuration, preventing delamination and reducing mechanical stress concentrations, thereby preserving mechanical stability while enabling the electrical connectivity benefits of stacked die.
Solution Approach 2:
The package structure utilizes composite materials including the underfill material (which may be epoxy-based or polymer-based) combined with the semiconductor die and interposer substrate. This composite construction provides both the electrical connectivity of closely-spaced die stacks and the mechanical stability of a unified, stress-distributed structure, as the different materials complement each other's properties.
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
Enhances thermal conductivity, mechanical stability, and electrical connectivity, enabling efficient heat dissipation and reliable connections in large panel formats and stacked die configurations, while simplifying the bonding process and improving yield.
Implementation Method 1
The underfill material may be applied utilizing a capillary underfill process
Implementation Method 2
The one or more semiconductor die may be bonded to the interposer die utilizing a mass reflow process or a thermal compression process
Implementation Method 3
The one or more semiconductor die may be bonded to the interposer die utilizing a mass reflow process
Data Source
AI summary
Methods for a semiconductor device package with a die-to-die first bond are disclosed and may include bonding one or more semiconductor die comprising electronic devices to an interposer die. An underfill material may be applied between the semiconductor die and the interposer die, and a mold material may be applied to encapsulate the semiconductor die. The interposer die may be thinned to expose through-silicon-vias (TSVs). The bonding of the semiconductor die may comprise adhering the semiconductor die to an adhesive layer, and bonding the semiconductor die to the interposer die. The semiconductor die may comprise micro-bumps for coupling to the interposer die, wherein the bonding comprises: positioning the micro-bumps in respective wells in a layer disposed on the interposer die; and bonding the micro-bumps to the interposer die. The semiconductor die may be bonded to the interposer die utilizing a mass reflow process or a thermal compression process.