Configuring a Semiconductor Production Control System with National Instruments Products

Holographic lithography is quickly emerging as the preferred method for patterning semiconductor substrates. One of the more difficult challenges in semiconductor production and the lithography process is the alignment of the mask and the wafer. Typically, wafers must be maintained at a fixed position relative to the lithography mask by means of actuators. The variation in position must be less than 0.2 um for a successful etch. For successful automation of the semiconductor production process, this step must be carefully controlled.

National Instruments offers a wide variety of tightly integrated DAQ, motion and real-time controllers to effectively solve the automation of the semiconductor lithography process.

A Typical Semiconductor Production Control System

In a typical lithography process, there could be six or more systems or stages. These system or stages consist of:
1. Loading substrate
2. Pre-alignment
3. Auto-focus & Auto-alignment
4. Scanning stages
5. Microscope alignment
6. Unloading substrate

Loading the substrate consists of placing the substrate on an air cushion. Once on the air cushion, two retractable reference pins are used for pre-alignment to align the wafer on a third pin at which control of the wafer switches from the air cushion to a vacuum which clamps the wafer to a chuck. The table has two axes for the X/Y direction and 3 axes for the vertical movement. For high-precision auto-alignment of the wafer and chuck piezo-actuators are used and controlled via a real-time control system to position and maintain this position between the wafer and the auto-focusing system. Several motorized stages will be used to perform raster scanning to uniformly expose the plate, one for the UV beam and one for the focus beam. Both beams are tightly synchronized in hardware. To perform the final alignment, microscopes are used in conjunction with a vision system to ensure that alignment marks in the hologram and on the substrate align.


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Benefits of Using National Instruments Control System with Integrated Data Acquisition and Motion

Software

Package	Description
NI Developer Suite LabVIEW Professional Control Edition (776678-09)	With LabVIEW, you can rapidly create automation applications using intuitive graphical development. LabVIEW integrates measurements, vision, and motion into one platform. The Professional Control Edition includes the LabVIEW Real-Time and LabVIEW Data Logging and Supervisory Control modules.
LabVIEW Real-Time (777844-03)	LabVIEW Real-Time and RT Series hardware deliver deterministic, real-time control needed for machine monitoring and test systems. You can choose LabVIEW RT Series hardware targets based on PXI and FieldPoint depending on the performance and I/O requirements of your industrial machine monitoring and control system.
LabVIEW Data Logging and Supervisory Control (778311-03)	LabVIEW Data Logging and Supervisory Control offers data management tools, such as easy-to-use I/O configuration for large-channel-count applications, automatic data logging, full alarm management and event logging, and real-time and historical trending. With easy networking, including a networked database for distributed logging, built-in security, and OLE for process control (OPC) connectivity, the LabVIEW Data Logging and Supervisory Control Module provides tremendous ease of use to get your high-channel-count system up and running quickly

PCI based Configuration

Function	Signal	Solution	Product
Real-Time Auto-focus and Wafer Alignment	Interferometer Position	Digital Input (32-bits)	NI PCI-6534 (778287-01)
Control System	Piezo-Actuator Control (Fine Resolution)	Multifunction DAQ Board (Analog Output)	NI PCI-6225 (779295-01)
	Motion and Robot Control	Motion Controller	NI PCI-7344 (778916-04)
Host Computer, Scanning, General Alignment and Positioning	Vacuum Control and General Purpose I/O	Digital I/O	NI PCI-6509 (778792-01)
General Control and Monitoring Functionality	Sensor Measurements	Multifunction DAQ board	NI PCI-6225 (779295-01)

PXI based Configuration

Function	Signal	Solution	Product
Real-Time Auto-focus and Wafer Alignment	N/A	Real-Time Controller	NI PXI-8106 RT (779887-33)
		PXI Chassis for the RT Controller	NI PXI-1031      (778932-01)
Control System	Interferometer Position	Digital Input (32-bits)	NI PXI-6534 (778288-01)
	Piezo-Actuator Control (Fine Resolution)	Multifunction DAQ Board (Analog Output)	NI PXI-6225 (779296-01)
Host Computer, Scanning, General Alignment and Positioning,	N/A	PC (PXI) Controller	NI PXI-8106 (779887-01)
		PXI Chassis for the Host Controller	NI PXI-1042        (778636-01)
General Control and Monitoring Functionality	Motion and Robot Control	Motion Controller	NI PXI-7344 (777935-01)
	Vacuum Control and General Purpose I/O	Digital I/O	NI PXI-6509 (778858-01)
	Sensor Measurements	Multifunction DAQ board	NI PXI-6225 (779296-01)
	PXI Bus Expansion	PXI Bridge (if needed)	NI PXI-8330 (777945-01)

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