Resistor Array Dummy Active Regions CMP Dishing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The dishing effect during the chemical-mechanical polishing (CMP) process in semiconductor manufacturing leads to instability in passive resistor connections and unpredictable resistance variations, affecting the performance and productivity of semiconductor devices.
Innovation Solution
A resistor array is designed with dummy active regions formed in the semiconductor substrate, which act as an anti-polishing medium to prevent the dishing effect, comprising isolation regions, unit resistors, and a dielectric layer to maintain flatness without increasing the occupation area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive resistors are formed on the semiconductor substrate surrounded by insulating materials, then the resistance stability and leakage current performance are improved, but the dishing effect during CMP process causes unpredictable resistance variation and connection instability
Solution Approach 1:
A dummy active region is introduced as an intermediary structure between the passive resistor and the semiconductor substrate. This dummy active region serves as a mediator that absorbs the dishing effect during CMP processing, preventing the polishing-induced deformation from directly affecting the passive resistor. The dummy active region is positioned adjacent to the passive resistor and is removed or isolated afterward, having served its protective function during the polishing process.
Solution Approach 2:
The dummy active region is formed in advance before the CMP process to preemptively counteract the dishing effect. By having this protective structure in place prior to polishing, the system prepares a counter-measure that prevents the harmful dishing effect from occurring in the first place, rather than trying to correct it afterward.
2Shape
If multiple CMP processes are performed to achieve desired flatness, then the global planarization is improved, but the dishing effect occurs during polishing due to material distribution variations
Solution Approach 1:
The dummy active region acts as a sacrificial intermediary that absorbs the differential polishing forces during CMP. By having this additional structure present during polishing, the material distribution becomes more uniform across the polishing surface, preventing the dishing effect while still achieving the desired global flatness through the CMP process.
3Reliability
If the occupation area is increased to prevent dishing effect, then the CMP process stability is improved, but the chip area increases
Solution Approach 1:
Instead of uniformly increasing the structure across the entire chip area, the dummy active region is strategically placed only in the local area adjacent to the passive resistor where the dishing effect occurs. This localized approach provides the necessary protection against dishing while minimizing the additional area occupied, maintaining high chip area utilization.
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 solution effectively prevents the dishing effect during CMP, enhancing the stability and accuracy of resistance values in semiconductor devices, thereby improving productivity and performance without increasing the chip area.
Implementation Method 1
A chemical-mechanical polishing (CMP) process, which is one conventional planarization method, is widely used to realize desired flatness.
Implementation Method 2
The plurality of dummy active regions are configured to function as an anti-polishing medium
Data Source
AI summary
A resistor array includes a semiconductor substrate, a plurality of isolation regions, a plurality of dummy active regions and a plurality of unit resistors. The plurality of isolation regions are formed in the semiconductor substrate. The plurality of dummy active regions are formed in the semiconductor substrate between the plurality of isolation regions. The plurality of unit resistors are formed on the plurality of dummy active regions.