Semiconductor Device Manufacturing via CMP Protrusion and Diffusion Bonding
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Solution Overview
Problem
The miniaturization of stacked semiconductor devices is limited by the short-circuiting of adjacent through-silicon-vias (TSVs) due to protrusions formed during the melting of metal bumps in the micro-bump method, which restricts the reduction of the minimum pitch between TSVs.
Innovation Solution
A semiconductor device manufacturing method involving chemical mechanical polishing (CMP) to form connection electrodes that protrude from the substrate surface, followed by diffusion bonding at a temperature below the melting point of the electrode material, preventing melting and subsequent short-circuiting, while increasing the contact area and bonding strength between electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the micro-bump method is used to bond TSVs by melting metal bumps, then bonding between electrodes is achieved, but protrusions from the melted bumps cause short-circuiting of adjacent TSVs and limit miniaturization
Solution Approach 1:
The invention changes the bonding mechanism from melting-based (micro-bump method) to diffusion bonding at temperatures below the melting point. This parameter change in bonding temperature and mechanism eliminates protrusion formation while maintaining bonding strength, thereby preventing short-circuits between adjacent TSVs and enabling device miniaturization.
Solution Approach 2:
The invention replaces the thermal-melting mechanism with a diffusion bonding mechanism. Instead of relying on melting and solidification of metal bumps, the process uses atomic diffusion at elevated temperatures to create bonds, fundamentally substituting the physical mechanism to eliminate harmful protrusions.
2Productivity
If the pitch between TSVs is reduced to enable miniaturization, then device density increases, but adjacent TSVs become more prone to short-circuiting from bump protrusions
Solution Approach 1:
By changing the bonding temperature parameter to be below the melting point and using diffusion bonding instead of melting, the invention eliminates protrusion formation. This allows adjacent TSVs to be positioned closer together without risk of short-circuiting, thereby enabling pitch reduction and increased device density.
3Manufacturing precision
If diffusion bonding is used at temperatures below the melting point, then short-circuiting is prevented and pitch between electrodes is reduced, but bonding strength must be maintained
Solution Approach 1:
The invention optimizes diffusion bonding parameters including temperature (below melting point), pressure, and time to achieve sufficient bonding strength while preventing protrusion formation. By carefully controlling these parameters, the process achieves both small pitch between electrodes and adequate bonding strength.
Solution Approach 2:
The invention performs preliminary preparation of electrode surfaces and control of bonding conditions before the actual bonding process to ensure that diffusion bonding achieves both precise pitch control and sufficient bonding strength. This includes surface treatment and parameter optimization prior to bonding.
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 reduces the pitch between connection electrodes, enhances bonding strength, and prevents short-circuiting, allowing for the miniaturization of semiconductor devices without compromising the integrity of the connections.
Implementation Method 1
The substrate is polished by chemical mechanical polishing (CMP) under conditions that a polishing rate of the metal is less that of the region surrounding the metal
Implementation Method 2
The connection electrodes, in a facing arrangement with each other, are bonded by heating to a temperature that is below the melting point of the metal of the connection electrodes
Data Source
AI summary
A method of manufacturing a semiconductor device includes forming an opening in a first substrate and filling the opening with a metal to form a first connection electrode. The first substrate is then polished by chemical mechanical polishing under conditions such that a polishing rate of the metal is less that of the region surrounding the metal. The chemical mechanical polishing thereby causes the first connection electrode to protrude from the surface of the first substrate. The first substrate is stacked with a second substrate having a second connection electrode. The first and second connection electrodes are bonded by applying pressure and heating to a temperature that is below the melting point of the metal of the first connection electrode.