Siloxane Polymer Hybrid Bonding for Semiconductor Wafers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hybrid wafer bonding techniques require a dedicated thermo-compression tool to ensure mechanical stability and electrical interconnection between semiconductor wafers, limiting the flexibility and efficiency of the process.
Innovation Solution
The use of siloxane polymers that shrink when cured, such as SC-480, SC-200, SC-300, SC-400, SC-500, SC-700, SC-800, and their mixtures, allows for hybrid bonding without additional compression, as they spontaneously stick together during the curing process, eliminating the need for a thermo-compression tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated thermo-compression tool is used to bond semiconductor wafers, then mechanical stability and electrical interconnection are ensured, but device complexity and process cost increase
Solution Approach 1:
The adhesive layer performs self-alignment and self-bonding through its inherent properties. The protruding portions of the adhesive layer automatically align with recesses on the opposing wafer during bonding, and the adhesive cures to create mechanical interlocking without requiring external compression tools or complex alignment mechanisms.
Solution Approach 2:
The invention changes the physical and chemical parameters of the adhesive layer by using a curable adhesive that transitions from a viscous state to a solid state. This parameter change enables the adhesive to flow and fill gaps initially, then harden to provide strong mechanical bonding and electrical connection, eliminating the need for continuous compression during curing.
2Reliability
If traditional hybrid bonding methods with metal embedded in polymer are used, then electrical interconnection is achieved, but additional compression equipment is required
Solution Approach 1:
The invention extracts and eliminates the dedicated compression tool from the bonding process. By designing the adhesive layer with protruding portions that mechanically interlock with recesses on the opposing wafer, the method removes the requirement for expensive and complex thermo-compression equipment while maintaining reliable electrical and mechanical bonding.
Solution Approach 2:
Instead of using compression force to achieve bonding, the invention inverts the approach by using the adhesive layer's own structural features (protruding portions) to create mechanical interlocking. The bonding force comes from the adhesive's curing process and mechanical interlocking rather than external compression, fundamentally reversing the traditional bonding mechanism.
3Ease of manufacture
If siloxane polymer coating is applied to both wafers, then spontaneous bonding occurs during curing, but polymer material consumption increases
Solution Approach 1:
The adhesive layer is applied selectively to specific regions of the wafer surface rather than uniformly across the entire surface. The protruding portions of the adhesive are positioned only where mechanical interlocking with recesses on the opposing wafer is needed, optimizing material usage while ensuring bonding at critical locations.
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 method enables robust bonding of semiconductor wafers with excellent electrical continuity and mechanical stability, reducing the complexity and cost of the bonding process while allowing for the fabrication of three-dimensional integrated devices like 3D image sensors without the need for specialized equipment.
Implementation Method 1
a coating layer of siloxane polymer not yet cured is deposited... said siloxane polymer being of a type that shrinks when cured
Implementation Method 2
the adhesive layers are cured to make them well adhere one to the other
Implementation Method 3
baking the two semiconductor wafers together one coupled to the other in an oven at a temperature and for a time sufficient to cure at a same time the portions of said siloxane polymer
Data Source
AI summary
A method to perform hybrid bonding of two semiconductor wafers without using a dedicated tool for thermo-compression is disclosed. According to the herein disclosed technique, the semiconductor wafers to be bonded together may be placed in an oven simply staying one upon the other without applying any additional compression between them besides their own weight. This outstanding result has been attained using of a particular type of thermosetting materials, namely siloxane polymers of the type that shrink when cured. Among these siloxane polymers, the siloxane polymers of the type SC-480, siloxane polymers of the series SC-200, SC-300, SC-400, SC-500, SC-700, SC-800 and mixtures thereof are particularly suitable.