# US 9,429,922 B2 · Method of process stability

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- Number: US 9,429,922 B2
- Document ID: US9429922B2
- Status: Granted
- Kind: B2
- Application number: 13/748,681
- Filed: 2013-01-24
- Published: 2014-07-24
- Granted: 2016-08-30
- Earliest claimed: 2013-01-24
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Co., Ltd.
- Inventors: Chih-Wei Hsu
- Web page: https://patentgrep.com/patent/US9429922B2

## CPC

- G05B 13/042: {in which a parameter or coefficient is automatically adjusted to optimise the performance}
- G05B 17/02: electric
- Y02P 90/02: Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

The present disclosure relates to an APC method and tool architecture to elaborate process stability, comprising a two-loop architecture for fine tuning by an APC loop and recovery tuning by an equipment performance optimization (EPO) loop of one or more process parameters. Fine tuning by the APC loop comprises neutralization of systematic drifts from manufacturing tool or the manufacturing process itself. Recovery tuning by the EPO loop comprises aligning processing tool conditions with their tool baseline configuration. The APC method and tool architecture establishes switching criteria for fine tuning of process parameters and recovery tuning of equipment parameters. A synergy mechanism is further established between the two loops, wherein adjustments to equipment parameters made by the EPO loop are recognized by the APC loop to avoid double-tuning. The APC method and tool architecture results in manufacturing process stability within a manufacturing process module.

## Claims

### Claim 1

A process control architecture, comprising:
an advanced process control (APC) loop configured to iteratively adjust a manipulated parameter value of a manufacturing tool within an APC tuning range based upon a process model, a pre-module inspection value, and a post-module inspection value, wherein the manipulated parameter value corresponds to a process parameter of a manufacturing process performed by the manufacturing tool;
an equipment performance optimization (EPO) loop configured to restore an equipment parameter value to a tool baseline value within a tool tuning range of the manufacturing tool if the pre-module inspection value or the post-module inspection value results from the manipulated parameter value falling outside the APC tuning range, wherein the EPO loop is configured to automatically restore the equipment parameter value to the tool baseline value without taking the manufacturing tool offline; and
a first switch configured to divert the post-module inspection value from the APC loop to the EPO loop if the post-module inspection value falls outside the APC tuning range of the APC loop, wherein the EPO loop comprises a kernel configured to receive the post-module inspection value from the first switch and to automatically determine a restoration value to the equipment parameter which restores the tool baseline value, and wherein the kernel is independent of the process model.

### Claim 2 (depends on 1)

The process control architecture of claim 1, configured to:
disable the EPO loop and enable the APC loop when a predicted manipulated parameter value determined by the process model, the pre-module inspection value, or the post-module inspection value is within the APC tuning range; and
disable the APC loop and enable the EPO loop when the predicted manipulated parameter value determined by the process model, the pre-module inspection value, or the post-module inspection value is outside the APC tuning range.

### Claim 3 (depends on 2)

The process control architecture of claim 2, wherein the post-module inspection value is determined upon completion of the restoration of the equipment parameter value to the tool baseline value and fed back to the APC loop to iteratively adjust the manipulated parameter value.

### Claim 4 (depends on 3)

The process control architecture of claim 3, the APC loop further comprising:
a process modeler configured to model process deviation from a process baseline value of the manipulated parameter value;
a filter configured to receive the post-module inspection value and the manipulated parameter value and produce a target delta value from a comparison of the post-module inspection value to a process target value derived from the manipulated parameter value; and
a controller configured to determine the manipulated parameter value from a first input comprising a pre-module inspection result and a second input comprising the target delta value received from the filter.

### Claim 5 (depends on 4)

The process control architecture of claim 4, wherein the kernel is configured to automatically identify a shift in the equipment parameter value from the post-module inspection value, and wherein the kernel is further configured to send the restoration value to one or more fabrication tools to restore the equipment parameter value to the tool baseline value.

### Claim 6 (depends on 5)

The process control architecture of claim 5, the EPO loop further comprising:
the first switch configured to divert the post-module inspection value from the filter to the kernel; and
a second switch configured to select between the target delta value and the restoration value as the second input to the controller;
wherein the first switch and the second switch are configured to switch simultaneously between the APC loop and the EPO loop.

### Claim 7

A process control architecture comprising an advanced process control (APC) loop, the APC loop comprising:
a process modeler configured to model process deviation from a process baseline value of a manufacturing process result controlled by a manipulated parameter, and to derive a post-module inspection value based on a manipulated parameter value of the manipulated parameter;
a filter configured to:
receive the post-module inspection value derived from the manipulated parameter value;
receive the manipulated parameter value;
derive a process target value from the manipulated parameter value, the process target value being a desired outcome of a manufacturing process; and
produce a target delta value from a comparison of the post-module inspection value to the process target value; and
a controller configured to determine the manipulated parameter value from a first input comprising a pre-module inspection value or a second input comprising the target delta value received from the filter;
wherein a first switch is configured to divert the post-module inspection value from the filter to an equipment performance optimization (EPO) loop configured to restore an equipment parameter to a tool baseline value if the post-module inspection value falls outside an APC tuning range of the APC loop, wherein the EPO loop comprises a kernel configured to receive the post-module inspection value from the first switch and to automatically determine a restoration value to the equipment parameter which restores the tool baseline value, wherein the kernel is independent of the process modeler.

### Claim 8 (depends on 7)

The process control architecture of claim 7, wherein the kernel is configured to send the restoration value to one or more fabrication tools to restore the equipment parameter of the one or more fabrication tools to the tool baseline value.

### Claim 9 (depends on 7)

The process control architecture of claim 7, wherein the EPO loop further comprises a second switch configured to select between the target delta value and the restoration value as the second input to the controller.

### Claim 10 (depends on 9)

The process control architecture of claim 9, wherein the first switch and the second switch are configured to switch simultaneously between the APC loop and the EPO loop.

### Claim 11 (depends on 10)

The process control architecture of claim 10, wherein the first switch is configured to send the post-module inspection value to the filter while the second switch is configured to simultaneously send the target delta value to the controller in an APC control loop mode, and wherein the first switch is configured to send the post-module inspection value to the kernel while the second switch is simultaneously configured to send the restoration value to the controller in an EPO control loop mode.

### Claim 12 (depends on 7)

The process control architecture according to claim 7, wherein the EPO loop is configured to automatically restore the equipment parameter to the tool baseline value without taking a manufacturing tool controlled by the APC loop offline.