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System and Methods for zero offset calibration of duplex manufacturing processes

IP.com Disclosure Number: IPCOM000223269D
Publication Date: 2012-Nov-15
Document File: 5 page(s) / 92K

Publishing Venue

The IP.com Prior Art Database

Abstract

This article comprises a new approach to control the alignment of a camera system for duplex measurement processes. Calibration of measurement processes from two sides.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 52% of the total text.

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System and Methods for zero offset calibration of duplex manufacturing processes

Background:

The technical area of this article is the enhancement of the calibration process of duplex manufacturing processes. Duplex means that a material is processed from two opposite sides.

Examples are:


• Silicon wafers for solar manufacturing


• Ceramic wafers for magnetic recording


• Micro-Electrical-Mechanical-Manufacturing (MEMS)

An example from the magnetic recording industry is shown in Fig 1, where the read/write head structure and it's serial number are located on the opposite side of a wafer.

In order to control and align the manufacturing process from two opposite sides an appropriate control mechanism with high precision is required.

Here we will layout a new measurement process to make this align and control mechanism easier, more reliable, more precise and better reproducible.

Fig 1: Example for a duplex manufacturing process from the magnetic recording industry.

Prior Art in summary exposes the following challenges:


• precise control of the opposite structures


• identify offsets to adjust the prior manufacturing process


• fast method


• possibility to easily reproduce the measurement

A Prior Art solution of the control measurement process is outlined in Fig 2 and Fig
3, Here Identical structures (ref 103 and 104) are generated on a calibration object on both sides.

The two cameras 101 and 102 measure the object from both sides. The object for calibration (100) is calibrated as a "gold" standard (e.g. at the PTB in Braunschweig). Fig 2 outlines a setup, where the top and bottom camera system is aligned without any offset.

Fig 3 outlines a setup where the top and bottom camera system is unaligned.

The identification of a mismatch depends here on the quality of the calibration of the "gold" standard.

Fig 4 outlines the design of such a gold standard. Here the two identical structures are created on both sides of the standard. The alignment here needs to be calibrated

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by an appropriate organization e.g. like the PTB in Braunschweig.

With a regular frequency the standard needs to be re-calibrated, in order to ensure that the standard did not change over time.

Fig 2: Prior Art calibration solution. Perfect aligned system.

Fig 3: Prior Art calibration process. Identification of a misaligned system using the gold standard.

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Fig 4: Prior Art design of a gold standard.

Summary:

This article comprises a new approach to control the alignment of a camera system for duplex measurement processes. Main differentiator to Prior Art solutions is a single object alignment instead of duplicated structure alignments on both sides.

A schematic outline of the solution is presented in Fig 5. Here two general approaches are described:

1. A transparent substrate is used for the standard (300). In this case the same structure can be used for both camera system calibrations.

2. U...