Trench Isolated Capacitor Integration Without New Masks
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Solution Overview
Problem
Existing semiconductor processing methods face challenges in integrating high-density trench capacitors into existing flows without adding complexity or requiring new masks, especially when trench structures are already present in integrated circuits.
Innovation Solution
A method to form a high-density trench capacitor simultaneously with a substrate contact using an existing process, which involves forming a trench, depositing dielectrics and polysilicon layers, and implanting dopants, adding minimal processing steps and no new masks to the existing flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If trench capacitors are added to existing substrate contact flows, then high density capacitance is achieved, but process complexity increases due to additional masks and flows
Solution Approach 1:
The patent combines the formation of trench capacitors with the existing substrate contact fabrication process. The same trench etching, dielectric deposition, and doping steps are used for both substrate contacts and trench capacitors, eliminating the need for separate process flows and masks. This merging approach achieves high density capacitance while avoiding additional process complexity.
Solution Approach 2:
The patent creates a universal process flow that serves dual purposes: forming both substrate contacts and trench capacitors. The trenches serve multiple functions - as contact structures in some regions and as capacitor containers in other regions. This multi-functionality allows the same process steps to produce different device types, reducing overall process complexity while maintaining high capacitance density.
2Adaptability or versatility
If new process masks are introduced for trench capacitor formation, then capacitor integration is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent employs a universal masking approach where the same masks used for substrate contact definition also define trench capacitor locations. The process uses existing mask sets that serve multiple purposes - defining both contact trenches and capacitor trenches. This eliminates the need for dedicated capacitor masks, maintaining manufacturing simplicity while achieving full capacitor integration capability.
3Quantity of substance
If existing trench structures are modified to accommodate capacitors, then high density capacitance is achieved, but existing trench structures may be impacted
Solution Approach 1:
The patent segments the wafer into different regions with different functions - some trenches become substrate contacts while others become trench capacitors. This segmentation is achieved through selective doping and fill processes after common trench formation. By segmenting the process rather than modifying existing structures, the integrity of substrate contact trenches is preserved while capacitor trenches are created with appropriate dielectric and conductive 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
Enables the integration of high-density trench capacitors with minimal additional processing steps and no new masks, simplifying the integration process while maintaining existing flow complexity, thereby addressing the need for high-density capacitance in integrated circuits.
Implementation Method 1
performing an anisotropic etch of the first dielectric to expose silicon at the bottom of the trench
Implementation Method 2
implanting a dopant into exposed silicon at the bottom of the trench
Data Source
AI summary
An integrated trench capacitor and method for making the trench capacitor is disclosed. The method includes forming a trench in a silicon layer, forming a first dielectric on the exposed surface of the trench, performing an anisotropic etch of the first dielectric to expose silicon at the bottom of the trench, implanting a dopant into exposed silicon at the bottom of the trench, forming a first polysilicon layer over the first dielectric, forming a second dielectric over the first polysilicon layer, and forming a second polysilicon layer over the second dielectric to fill the trench.