JP2003322520A - Flatness and shape measuring device for surface plate for surface grinding/polishing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems that an article used as a measurement reference is required to be carried in a device or separately, and that the article is large and very expensive and must be managed and stored, while keeping its accuracy, and that movement is required in order to perform both measurement of the reference article and measurement of a surface to be measured, to thereby deteriorate remarkably the measurement accuracy. <P>SOLUTION: The flatness and the surface shape are determined by using a mechanism for moving in parallel with the measuring surface, a measuring device having a measurement criterion inside the device capable of calculating a deflection/shape change caused by the self-weight or exerting no influence on the measurement accuracy, for measuring the reference surface, distance information to the measuring surface or the reference surface, the deflection quantity caused by the self-weight of the reference surface determined by calculation, and the horizontal direction moving quantity to the measuring surface. A wire rod having a small sectional area or a thin plate material is used as the reference article for measurement and stored compactly inside the device. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to flatness of surface plate and pad surface (measurement surface) of a surface grinding / polishing device for semiconductor wafers, liquid crystal glass, glass disks for hard disks, aluminum disks for hard disks, crystal oscillators and the like. And a measuring device for measuring a shape.

[0002]

2. Description of the Related Art In a conventional surface grinding / polishing device, two surface plates which are arranged to face each other and rotate relative to each other or one surface plate which rotates only on one side and a workpiece are held (pressed and held) and held. In the device (FIGS. 1 and 2) for processing the workpiece sandwiched by the tool, each of the surface plates (processing surface and processing reference surface) or the polishing pad / polishing grindstone (processing surface) attached to each surface plate is used. Flatness has a great influence on the processing accuracy of the workpiece. These surface grinding / polishing devices are used, for example, for flattening semiconductor wafers, liquid crystal glass, hard disk glass, and the like.

In recent years, the demands on the flatness of semiconductor wafers, liquid crystal glass, etc. have become extremely high, and in order to meet these demands, the surface plate (processing surface and processing standard of a surface grinding / polishing device is required. The flatness of the surface is an important factor. That is, the shape of the surface plate is controlled to be flat or slightly changed to be convex or concave, but the flatness of the workpiece is improved.

As the shape of the surface plate becomes important,
It is required to precisely measure the flatness of the surface plate. Therefore, various devices for measuring flatness and shape have been proposed.

For example, Japanese Patent Application Laid-Open No. 8-61949 proposes a surface shape measuring device for a surface plate and a polishing pad. In this device, a means for measuring the distance to the surface plate or the polishing pad and a surface plate are used as the measuring means. The shape is measured by means of moving means for moving them substantially in parallel and means for processing distance information to the surface plate or the polishing pad stuck on the surface plate obtained by these means.

However, all of these devices are
Before measuring or when the device is manufactured, the device stores the standard of flatness and shape on the stone surface plate and straight edge, which are the standard of flatness and shape, and the device is based on the stored data. The flatness or shape is measured by moving it onto the surface plate to be measured and measuring the distance to the surface plate and the polishing pad. For this reason, these devices have a standard (flat stone, straight edge, etc.) that serves as a standard for flatness and shape, and must be stored and managed so that the accuracy of these standards is maintained. In addition, the criteria for the flatness and shape are very expensive and not easy to manage.

Also in the convenience of use, after the reference data is measured and stored according to the reference, the measuring device is moved based on the data, and the device is moved onto the surface plate or the polishing pad attached to the surface plate. Since it is measured afterwards, the flatness and shape will be significantly affected by the distortion of the frame and the installation environment such as whether the measuring device is placed horizontally depending on the condition of measuring the reference data and the condition of moving the measuring device. It is thought to affect.

Moreover, in recent years, due to the large size of the equipment, the diameter of the surface plate has become very large (φ2000 mm or more), so that the criteria for flatness and shape have become large, which is very expensive and easy to manufacture. Difficult to use and manage storage.

[0009]

Conventionally, a device (stone surface plate, straight edge, etc.) is always used as a measurement reference when measuring the flatness and shape of a surface plate and a polishing pad attached to the surface plate. It must be held inside or separately, and the reference item is very expensive, and the reference item must be stored and managed with high accuracy.

Further, the state measured by a reference and the state actually measured by moving onto the surface plate and the polishing pad vary depending on the installation environment, and the measurement accuracy is remarkably deteriorated.

[0011]

[Objective] The present invention has been made in view of the above problems, and serves as a reference for the flatness and shape separately from the apparatus when measuring the flatness and shape of the surface plate and the polishing pad attached on the surface plate. On the surface plate and surface plate, there is no object (stone surface plate, straight edge, etc.), and a standard surface plate that is cheap and easy to manage is used on the surface plate to be measured and the polishing pad attached to the surface plate. It is an object of the present invention to provide a device capable of measuring the flatness of a polishing pad attached to a substrate with higher accuracy.

[0012]

In the measuring device according to the present invention, by making the cross-sectional area of a reference object small, the deflection / shape change due to its own weight does not affect the measurement accuracy, or the measurement can be performed. Therefore, it can be installed inexpensively and compactly in the device. This measuring device is a means for pulling horizontally a wire rod having a small cross-sectional area and a uniform material or a thin plate material having a flattened measurement surface as a reference surface for measurement with a constant tension (the above-mentioned reference) And a means for measuring the length by contacting or separating from the reference surface, and a length measuring instrument such as a linear scale that comes into contact with the surface plate of the surface grinding / polishing device or the polishing pad (measurement surface) attached to the surface plate, Alternatively, a laser displacement sensor or the like for measuring the distance to the upper end of the probe in contact with the measurement surface is provided, and means for moving these in parallel to the reference surface / measurement surface is provided. Further, it is provided with a signal processing means for obtaining the flatness and the surface shape by using the distance information to each of the reference surface and the measurement surface, the amount of deflection of the wire and thin plate material obtained by calculation, and the amount of horizontal movement with respect to the measurement surface. There is.

[0013]

EXAMPLE An example of the measuring apparatus of the present invention is shown in FIGS.
It will be described based on.

In this example, the laser length measuring device in FIG. 4 and FIG. 5 is used, and the horizontal wire rod position is used as a reference. Depending on the accuracy required and the object to be measured, any length measuring device such as a linear scale or eddy current type can be used. Whether the wire rod is used for the reference plane depending on the horizontal movement distance and the selected measuring device is used. No. 3: It is optional to use a plate material. The length measuring device may measure the reference surface (wire material / plate material) and the measurement surface (surface plate, etc.) simultaneously (in this example) or individually.

In this example of the apparatus, first, the deflection of the wire serving as the reference surface is calculated, and the result is stored in the computer. This device is installed on the object to be measured, and the motor for moving the length measuring device is driven in the horizontal direction to scan the measurement surface. The motor rotation amount at this time is used as position information of the non-measurement object, and length measurement data (reference plane / measurement plane distance) is taken in synchronization with this. Since the shape of the object to be measured can be calculated in real time from the difference between the reference surface distance and the measurement surface distance, it is not necessary to measure the reference surface as in the conventional case, and highly accurate measurement can be performed with one scan. The results are output to a display / printer.

When a plate material is used, it is impossible to calculate the flatness of the plate material measurement surface by calculation. Therefore, it is necessary to save the result of the precise measurement in advance in the computer. However, when a contact type linear scale etc. is selected as the length measuring device, or when the horizontal movement distance is short, etc.
Cost performance is superior to that using a laser length measuring machine.

FIG. 7 shows an example of the result of measuring the surface plate surface using the apparatus of the present invention. In the graph, the horizontal axis is the measurement position (mm) in the diameter direction of the surface plate, and the vertical axis is the flatness (μm) of the surface plate.
Respectively.

[0018]

According to the present invention, since a highly accurate flatness reference surface can be realized inexpensively and compactly, it is inexpensive regardless of the size of the surface grinding / polishing device surface plate requiring planarization. It is possible to provide a device that is easy to use, can be easily stored and managed, can perform highly accurate measurement, and can measure the flatness of a surface grinding / polishing device surface plate that is larger.

[Brief description of drawings]

FIG. 1 Surface grinding / polishing device 1 (functional schematic)

[Fig. 2] Surface grinding / polishing device 2 (functional schematic)

[Fig. 3] Flatness profile measuring instrument 1 (outline)

FIG. 4 Flatness shape measuring instrument 2 (outline view)

FIG. 5 Detailed view of measuring unit 2

[Figure 6] Control function block diagram

FIG. 7: One measurement result

Claims (4)

[Claims] 1. A measuring device for measuring the flatness and shape of a surface plate and a pad surface (measurement surface) of a surface grinding / polishing device, which comprises a surface plate and a pad surface (measurement surface) of the surface grinding / polishing device.
There is a measuring instrument that can measure the length measurement of the device, and a measurement standard that can calculate the deflection and shape change due to its own weight or that does not affect the measurement accuracy inside the device. And a mechanism for moving the measuring instrument of the above-mentioned surface plate surface and the pad surface and the measuring instrument that serves as the reference for measurement or a device that can measure them at the same time in parallel to the measuring surface, and the above-mentioned surface plate surface and the pad surface or the reference surface A flatness and shape measuring instrument having signal processing means for obtaining flatness and surface shape using distance information to an object, a deflection amount due to its own weight of a reference object obtained by calculation, and a horizontal movement amount with respect to a measurement surface. 2. By having a measuring reference and its measuring device inside the apparatus, it is not necessary to separately provide a surface plate, a straight edge or the like as a measuring reference separately from the apparatus. 3. A wire rod having a small cross-sectional area and a uniform material, or a thin plate material having a flattened measurement surface is used as a reference for measurement, and the wire is flexed by its own weight by horizontally pulling them with a constant tension. Shape change does not affect measurement accuracy,
Alternatively, the device can be manufactured inexpensively and compactly because it can be calculated, and by changing the length of the device, a long measuring device, which has been difficult to manufacture in the past, can be manufactured inexpensively and easily. 4. The measurement can be performed at the same measurement position as the measurement of the reference surface and the actual measurement of the surface plate and the pad surface, and it is not necessary to move the device. Therefore, movement of the frame causes a difference in the installation environment and the like. Since it does not affect the measurement result, accurate measurement is possible.