Semiconductor Through-Connection via Insulating Trench and Via-Middle Process
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Solution Overview
Problem
Existing methods for producing electrical through-connections in microelectromechanical systems face challenges such as poor insulating layer quality, thermal damage due to differing expansion coefficients, and difficulties in grinding and metal smearing, particularly in via-last and via-middle processes.
Innovation Solution
A via-middle approach is adopted where a ring-shaped insulating trench is created on the semiconductor substrate's front side, filled with insulating material, and a contact hole is opened on the back side, allowing for metal deposition after the semiconductor wafer has been thinned, thus avoiding exposure to elevated back-end process temperatures and reducing the risk of thermal damage and metal smearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If insulating material is deposited in deep holes with high aspect ratio using low-temperature processes, then the deposition can be achieved, but the insulating layer quality is poor and thickness is limited
Solution Approach 1:
The patent performs the metal filling operation before the back-end grinding process, rather than after. This preliminary action allows the metal to be deposited when the wafer is still intact and accessible from both sides, avoiding the subsequent problems of metal smearing during grinding and thermal damage during high-temperature back-end processes. The through-connection structure is prepared in advance with proper insulation and barrier layers.
2Ease of operation
If the wafer is ground deeply to expose metal filling in via-middle processes, then contact areas can be accessed, but metal smearing over the oxide insulating surface occurs
Solution Approach 1:
The patent performs the metal filling operation before the back-end grinding process, rather than after. This preliminary action allows the metal to be deposited when the wafer is still intact and accessible from both sides, avoiding the subsequent problems of metal smearing during grinding and thermal damage during high-temperature back-end processes. The through-connection structure is prepared in advance with proper insulation and barrier layers.
3Manufacturing precision
If through-connections are produced in via-last approaches at the end of wafer process, then vertical contacts with small base area are achieved, but thermal damage occurs due to differing expansion coefficients during back-end processes
Solution Approach 1:
The patent performs the metal filling operation before the back-end grinding process, rather than after. This preliminary action allows the metal to be deposited when the wafer is still intact and accessible from both sides, avoiding the subsequent problems of metal smearing during grinding and thermal damage during high-temperature back-end processes. The through-connection structure is prepared in advance with proper insulation and barrier layers.
4Ease of operation
If grinding is performed to expose metal filling, then contact areas become accessible, but the process becomes difficult due to multiple materials needing to be ground simultaneously
Solution Approach 1:
The patent performs the metal filling operation before the back-end grinding process, rather than after. This preliminary action allows the metal to be deposited when the wafer is still intact and accessible from both sides, avoiding the subsequent problems of metal smearing during grinding and thermal damage during high-temperature back-end processes. The through-connection structure is prepared in advance with proper insulation and barrier layers.
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 through-connections with improved insulating layer quality, reduced risk of leakage currents and capacitive interferences, and simplified processing, while avoiding thermal damage and metal smearing issues, allowing for thicker insulating layers and adaptable volume resistance.
Implementation Method 1
the holes are completely or partially filled with a metal. The filling is carried out either with the aid of a chemical vapor deposition (CVD) process or by depositing a metal layer with the aid of an electroplating process
Implementation Method 2
the deposition of insulating material in the deep holes having a high aspect ratio may be achieved only in small thicknesses due to technical reasons
Data Source
AI summary
A method for manufacturing a component having an electrical through-connection is described. The method includes the following steps: providing a semiconductor substrate having a front side and a back side opposite from the front side, producing an insulating trench, which annularly surrounds a contact area, on the front side of the semiconductor substrate, filling the insulating trench with an insulating material, producing an electrical contact structure on the front side of the semiconductor substrate by depositing an electrically conductive material in the contact area, removing the semiconductor material remaining in the contact area on the back side of the semiconductor substrate in order to produce a contact hole which opens up the bottom side of the contact structure, and depositing a metallic material in the contact hole in order to electrically connect the electrical contact structure to the back side of the semiconductor substrate.