Wafer Pattern Registration Control for Semiconductor Manufacturing
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Solution Overview
Problem
Current methods for controlling pattern positioning in manufacturing processes, such as semiconductor device production, rely on overlay measurements that only provide relative positions, limiting the ability to predict and correct the placement of patterns in subsequent layers, and require specialized metrology targets that are not feasible for functional patterns.
Innovation Solution
A method that conducts registration measurements on patterns using tools like IPRO series, SEM, or HIM to determine their position in a common coordinate system, allowing for feed-forward control and direct measurement of functional patterns, thereby enabling precise placement and reducing errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If overlay measurements are used to control pattern positioning, then relative position information can be obtained, but feed-forward control is not possible and only specially designed metrology targets can be measured
Solution Approach 1:
The patent applies universality by enabling the measurement system to handle both specially designed metrology targets and functional patterns using the same registration tool and methodology. The system is made multi-functional by removing the restriction that limited measurements to only dedicated OVL targets, allowing the same apparatus to measure any pattern type including actual functional structures.
Solution Approach 2:
The patent uses copying by creating a digital representation (coordinate data) of the measured pattern positions that can be stored and reused for feed-forward control. The registration measurement results are copied into a usable format that informs subsequent lithography steps, eliminating the need for repeated physical measurements of the same features.
2Loss of information
If overlay measurements are performed after layers are placed and patterned, then relative position information is available, but the information cannot be used to predict or correct positions of patterns yet to be placed
Solution Approach 1:
The patent applies preliminary action by performing registration measurements on previously formed patterns before the subsequent lithography step is executed. The measurement results are obtained in advance and used to calculate and apply corrections to the lithography tool setup, preventing positioning errors before they occur in the next layer rather than detecting them after the fact.
Solution Approach 2:
The patent implements feedback by using the registration measurement results from previous layers to adjust and control the positioning in subsequent lithography steps. The measured position information feeds back into the lithography tool control system, creating a closed-loop process that continuously corrects positioning drift and ensures accurate pattern placement across multiple layers.
3Ease of manufacture
If metrology targets are used for OVL measurements, then measurement capability is provided, but the targets are larger than 10 μm by 10 μm and cannot be placed in the vicinity of functional patterns
Solution Approach 1:
The patent applies parameter changes by fundamentally altering the size parameter of the measurement targets from the conventional 10 μm by 10 μm metrology targets to much smaller dimensions. This parameter change enables the placement of measurement references in close proximity to functional patterns where they are actually needed, without occupying excessive area or interfering with device 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 approach improves manufacturing yield, reduces reaction time to process excursions, and simplifies control by allowing direct measurement and correction of individual pattern placements, increasing efficiency and accuracy.
Implementation Method 1
The registration measurement may be an optical registration measurement, done for example with a registration tool of the IPRO series available from KLA Tencor
Implementation Method 2
The registration measurement may also be based on a particle beam, employing methods like Scanning Electron Microscopy (SEM) or Helium Ion Microscopy (HIM)
Implementation Method 3
OVL metrology based on optical images and/or on optical scatterometry
Data Source
AI summary
In a method for controlling the positioning of patterns on a substrate in a manufacturing process at least one registration measurement is conducted with a registration tool on at least one pattern formed in at least one layer on the substrate by a previous process step of the manufacturing process. From the registration measurement a position of the at least one pattern in a coordinate system is determined. The determined position of the at least one pattern is fed into an automatic process control of a manufacturing system for controlling a setup of the manufacturing system for a subsequent process step of the manufacturing process. The manufacturing process may be a wafer manufacturing process with a silicon substrate. Complementary information may be collected in addition to performing the registration measurement and fed to the automatic process control. The process steps may for example include lithography steps, etching steps, layer deposition.