Contact Via Placement via DSA Hardmask Template
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Solution Overview
Problem
Current methods for forming contact vias through Directed Self Assembly (DSA) face challenges in achieving accurate pattern placement, which is crucial for advanced semiconductor devices and future CMOS integration processes.
Innovation Solution
A method involving a substrate with contact structures embedded in a dielectric layer, where a patterned template layer with evenly distributed openings of identical size is used to guide the DSA process, ensuring precise placement of contact vias by using a Block Copolymer material and a hardmask layer to control the etching process, thereby improving pattern placement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a template layer is used to define openings for DSA process, then the contact hole pattern can be formed, but the pattern placement accuracy is difficult to control
Solution Approach 1:
The hardmask layer is patterned in advance to define regions where contact holes should NOT be formed. This preliminary patterning guides the subsequent DSA process, ensuring that block copolymer material only assembles in desired locations. The pre-defined hardmask pattern serves as a negative template, simplifying the overall process control while achieving precise placement accuracy.
Solution Approach 2:
The hardmask layer acts as an intermediary between the substrate and the DSA process. It translates the desired contact hole placement pattern into a physical mask structure that guides block copolymer self-assembly. This intermediary layer enables precise pattern transfer while decoupling the complexity of DSA process control from the final pattern accuracy.
2Productivity
If Block Copolymer material is provided in all openings of the template layer, then self-assembly occurs, but unwanted via pattern transfer may occur
Solution Approach 1:
The hardmask layer is patterned in advance to prevent block copolymer material from assembling in unwanted regions. By creating a protective mask structure before the DSA process, the method proactively blocks potential erroneous via formation. This preliminary protective action ensures that even if block copolymer is provided in all template openings, only desired locations will result in actual via patterns after etching.
3Stability of the object's composition
If the template layer openings are evenly distributed, then uniform BCP filling occurs, but the process complexity increases
Solution Approach 1:
The uniformly distributed opening pattern in the template layer is copied to the hardmask layer through the DSA process. The block copolymer self-assembles in a pattern that replicates the template's uniform distribution, ensuring consistent via spacing and uniform material filling. This copying mechanism transfers the geometric uniformity from template to final pattern without requiring complex direct fabrication.
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 enhances the accuracy of contact via pattern placement, preventing unwanted via pattern transfer and ensuring uniform filling of the Block Copolymer material, thus supporting advanced semiconductor device integration.
Implementation Method 1
inducing polymer separation of the BCP in the openings
Data Source
AI summary
A method for forming contact vias includes providing a substrate comprising a plurality of contact structures embedded in a first dielectric layer, the contacts abutting an upper surface of the first dielectric layer. The method also includes providing a second dielectric layer on the upper surface of the first dielectric layer, and providing contact vias in the second dielectric layer by patterning the second dielectric layer at least at positions corresponding to the contact structures, wherein patterning the second dielectric layer comprises using a DSA patterning technique.