JPS6324407Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is designed to measure the flatness of the surface of the object to be measured (hereinafter referred to as
The present invention relates to an optical interference fringe measurement device that measures the flatness (referred to as flatness).

Optical interference fringe measurement devices that measure the flatness of objects to be measured, such as wafers, installed on a wafer fixing device include those in which the object to be measured is placed on a reference mirror surface provided in the main body of the measurement device, and those in which the object to be measured is placed on a reference mirror surface provided in the main body of the measurement device. There is one in which a reference mirror object is placed on the measurement object. Further, the reference mirror surface body and the object to be measured may be brought into contact by bringing their opposing surfaces into full contact with each other, or by interposing a protrusion or the like between the two to bring them into partial contact. Optical interference fringe measurement devices that employ a mechanism in which a reference mirror is placed on a protrusion on the object to be measured are most commonly used, but in either method, measurement accuracy is not guaranteed. In order to increase this, it is desirable to minimize the contact pressure of the reference specular body against the object to be measured to prevent occurrence of elastic strain on the surface to be measured of the object to be measured.

This invention was made in view of these points,
An object of the present invention is to provide an optical interference fringe measuring device that improves measurement accuracy by preventing the occurrence of elastic strain on a surface to be measured of an object to be measured.

Embodiments of the present invention will be described below with reference to the drawings.

The figure is a sectional view of one embodiment of the present invention. 1 in the figure is a cylindrical device main body. A locking member 2 is provided protruding from the inner circumferential surface of the opening 1a of the device body 1. A screw hole 4 a is bored in the locking member 2 along the longitudinal direction of the device main body 1 . Screw hole 4a
An adjustment screw 4 is fitted into the. Adjustment screw 4
A collar 4b for a spring receiver is provided in the middle of the
A spring member 3 is engaged thereon. The upper end of the adjustment screw 4 is passed through a hole 5a bored in the edge of a substantially dish-shaped holding member 5 housed within the device main body 1. A window 5b is opened in the center of the holding member 5, into which the upper part of the object to be measured 6 housed in the opening 1a of the apparatus main body 1 is inserted. A reference mirror body 7 is fitted into the dish-shaped recessed portion 5c of the holding member 5. The reference mirror body 7 is adapted to locally contact the surface to be measured 6a of the object to be measured 6 via a protrusion 7b formed on its lower surface 7a. The reference mirror body 7 is attached to a fixing member 8 provided on the upper part of the holding member 5.
Fixed by A holding member receiver 9 is attached to the locking member 2 directly below the edge of the holding member 5 so that its tip is close to the holding member 5.

Next, the operation of this device will be explained. first,
This device adjusts the position of the lower end of the spring member 3 using the adjustment screw 4 during manufacturing or prior to measurement work, and when the object to be measured 6 is not placed under the reference mirror surface 7 as shown in the figure, the holding member 5 and the holding member receiver 9 is determined to be zero or a small value. Note that even when this distance S is zero, the load of the holding member 5 acting on the holding member receiver 9 is slightly suppressed, and the setting is made such that the spring member 3 receives most of the load. In this setting, since the spring constant of the spring member 3 can be known in advance, the spacing S is gradually reduced by turning the adjusting screw 4 from the state where the spacing S exists, until the spacing S becomes zero. This is done by further turning the adjusting screw 4 by a predetermined amount from the relaxed state, and the holding member receiver 9 and the spring member are lowered by the lowering amount of the adjusting screw 4 which is lowered by further turning the distance S from the state where the distance S has become zero. It is possible to appropriately determine the load ratio of the holding member 5 that acts on the holding member 3.

Measurements are carried out with this device set up as described above. During measurement, the surface to be measured 6a of the object to be measured 6 is positioned within a predetermined height range from the top surface of the base 11, and the When the apparatus body 1 is placed on the base 11 so that the upper part of the object to be measured 6 enters the window 5b of the holding member 5, the surface to be measured 6a
comes into contact with the protrusion 7b of the reference mirror body 7 and lifts it so that the above-mentioned interval S is slightly increased from the above-mentioned initial state.

Therefore, if measurement is performed by positioning the reference mirror surface 7 on the object to be measured 6 and placing the main body 1 on the base 11 as described above, the surface to be measured 6a and the protrusion 7b
The object to be measured 6 is brought into contact with the reference specular body 7 reliably by lifting it, and the contact pressure increases as the distance S increases due to the lifting of the reference specular body 7, that is, the spring member 3 stretches. This is only the reduction in the load that the spring member 3 receives. The amount by which the load decreases due to the elongation of the spring member 3 is determined by the spring constant of the spring member 3 and the amount of elongation. By keeping the contact pressure within a relatively narrow range, the contact pressure can be set to a sufficiently small value.
In addition, in the initial state, when the holding member 5 is in contact with the holding member receiver 9 and this holding member receiver 9 receives part of the load of the holding member 5, the expansion of the spring member 3 In addition to the accompanying load, the load received by the holding member receiver 9 also acts between the surface to be measured 6a and the protrusion 7b. Therefore, adjusting screw 4
By adjusting the holding member receiver 9 as described above,
By appropriately determining the load that the holding member 5 receives, it is possible to easily bring the contact pressure close to a predetermined value most suitable for measurement.

Therefore, the measurement can be performed with almost no distortion occurring on the surface to be measured 6a, and the protrusions 7b and the surface to be measured 6a are brought into reliable contact with each other, and the flatness can be measured with extremely high accuracy.

As explained above, according to the optical interference fringe measuring device 10 according to the present invention, by adjusting the spring member provided between the holding member and the holding member receiver in advance with the adjustment screw, the reference mirror surface relative to the object to be measured can be adjusted. It is possible to ensure contact by reducing the contact force of the body to a smaller value, thereby preventing the generation of elastic strain on the surface to be measured, and making it possible to measure flatness with extremely high accuracy.

[Brief explanation of the drawing]

The figure is a sectional view of one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Device main body, 2... Locking member, 3... Spring member, 4... Adjustment screw, 5... Holding member, 5a...
...hole, 6... object to be measured, 7... reference specular object, 7a
...Lower surface, 7b...Protrusion, 8...Fixing member, 9
... Holding member receiver, 10 ... Optical interference fringe measuring device,
11... Base, 12... Monochromatic light.

Claims (1)

[Scope of utility model registration request] A reference specular body through which interference light passes, a holding member that holds the reference specular body, the holding member and the reference specular body are housed, and the reference specular body is attached to the object to be measured directly or through a protruding member. an apparatus main body having an opening for contacting and opposing each other; and a device body configured to support the holding member with zero to a small distance from the holding member along the direction in which the object to be measured and the reference mirror surface face each other. a holding member receiver formed on the apparatus main body; a spring member interposed between the holding member receiver and the holding member; An optical interference fringe measuring device characterized by comprising an adjustment screw for adjusting the distance between the receivers and the force acting on the spring member.