JPH0524005Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an apparatus for measuring the thickness of a wafer. More specifically, it is possible to freely change the position of the wafer that is the object of measurement, and to measure wafers of several sizes without having to change the jig for positioning the wafer or change its mounting position. It is possible to measure the thickness of
Furthermore, the present invention aims to provide a measuring stand that enables highly accurate measurements.

[Prior art] For example, the thickness of an IC board wafer, etc. is measured without touching the object using a displacement sensor that measures the distance between the object and the object by measuring capacitance. A conventional device is shown in FIG. 7 and will be explained. A is a side view, and b is a plan view.
A wafer 22 is placed on a surface plate 21, its position is determined using a stopper 23, and the thickness of the wafer 22 is measured by sandwiching the wafer 22 between an upper displacement sensor 25 and a lower displacement sensor 26 without contact.

FIG. 8 shows another conventional example, in which a is a side view and b is a plan view. The thickness of the wafer 22 was measured by placing the wafer 22 on a three-ball seat 24 provided on the surface plate 21 and sandwiching the wafer 22 between the upper and lower displacement sensors 25 and 26.

[Problems to be solved by the invention] With such conventional measuring devices, when measuring the thickness of a wafer at multiple measurement points, it is necessary to pinch the wafer with tweezers each time. The position had to be changed, and for example, when measuring the thickness at five locations, the above operation had to be repeated five times.

Therefore, a large number of measurement steps were required, and a long time was required for measurement, resulting in poor measurement efficiency. Therefore, there are many opportunities to touch the wafer, which is the object to be measured, using tweezers or the like, which makes it easy to scratch, resulting in quality problems.

In addition, as the wafer moves, it is difficult to obtain parallelism of the wafer to the surface plate due to the presence of dust on the surface plate, warpage of the wafer, and its unevenness, and other equipment such as vacuum suction is required. It was hot.

Since it is difficult to obtain parallelism of the wafer to the surface plate, it is also difficult to obtain parallelism to the opposing surfaces of the displacement sensors installed above and below the wafer, resulting in poor measurement reproducibility and insufficient measurement accuracy. There was a problem that it could not be done.

In order to carry out such measurements quickly and without damaging the wafer, a considerable level of skill is required, and without this skill it is difficult to achieve efficient and highly accurate measurements.

Furthermore, when measuring the thickness of each point on a wafer of different size, if the device is one that places the wafer directly on a surface plate (Fig. 7), the positional relationship with the displacement sensor must be adjusted. Therefore, the position of the stopper had to be changed each time. In addition, in the case of a device that measures the wafer by placing it on a three-ball holder (Figure 8), the three-ball holder itself must be replaced each time with one that is compatible with the size of the wafer, which requires a large amount of measurement man-hours. In addition to the poor measurement efficiency, a three-ball seat of a size corresponding to the size of the wafer was required, which had to be prepared separately.

As described above, conventional thickness measuring devices using displacement sensors have problems in that they are inefficient in measurement, and have large errors and variations in measured values for each measurement, making it difficult to achieve accurate thickness measurements. The dot was hot.

[Means for solving the problem] In order to solve the problem, the present invention provides a means for moving the wafer.
The purpose is to efficiently and accurately measure the thickness of a wafer.

For this purpose, a pair of displacement sensors supported by upper and lower mounting means, and a plurality of guide parts that hold only the peripheral portions of wafers of various sizes are used to place wafers of various sizes whose thickness is to be measured by the displacement sensors. A swivel base that can rotate in 90° steps, a movable base that can freely move back and forth (or left and right) on which the swivel base is placed, and a guide means for sliding the movable base are provided. The structure is such that it can be combined with a base.

[Function] With this structure, the swivel table and the moving table can change the position of the entire wafer by a combination of their operations without touching the wafer and without changing the positional relationship of the wafer itself with respect to the guide surface of the guide means. The wafers can be placed on the same plane so that they can be set as desired, and the swivel table can mount wafers of several sizes.

[Embodiment] Hereinafter, the configuration of an embodiment of the present invention will be described as shown in FIGS. 1 to 5.

FIG. 1 is a side view, FIG. 2 is a plan view, and FIGS. 3 and 4 are partial side sectional views.

25 is an upper displacement sensor, and 26 is a lower displacement sensor, which are attached to the upper mounting part 2A and the lower mounting part 2B. Upper and lower mounting parts 2A, 2
B has a pinion 3 and a rack 4 engaged with each other, and can move up and down by rotating the pinion 3, and upper and lower displacement sensors 2
Adjust the measurement positions in the vertical direction of 5 and 26. The mechanism for making fine adjustments up and down using the combination of the pinion 3 and the rack 4 is the same as, for example, the mechanism for moving the lens barrel of a microscope up and down.

Reference numeral 5 denotes a turning table on which the wafer 22 is mounted, and as shown in Fig. 2, it is formed into a disk shape. As shown in FIG.
A cross-shaped hollow portion 7 larger than the maximum diameter of the guide portion 6a is formed to avoid the upper and lower displacement sensors 25 and 26.

Further, on the lower surface, a raceway groove 8 for a three-point support ball bearing seat 10 having balls 27 at three points is provided in an annular shape.

By providing guide portions 6a, 6b, 6c, and 6d with several different diameters, wafers 22 with different diameters can be
Since a cross-shaped hollow part 7 (FIG. 2) larger than the maximum diameter of the guide part 6a is formed, this hollow part 7
Insert tweezers etc. into the guide parts 6a-6.
The wafer 22 mounted on the guide portion 6a (in FIG. 4) can be easily taken out. In FIG. 2, swivel base guides 15 are provided at four locations around the swivel base 5 to ensure smooth rotation of the swivel base 5.

Reference numeral 9 denotes a movable table on which the swivel table 5 is placed and moves back and forth, which is formed into a rectangular shape as shown in FIG. 3, and a three-point support ball bearing seat 10 shown in FIG. The swivel base 5 is mounted in such a state that this and the raceway groove 8 on the lower surface of the swivel base 5 fit together. Since the swivel base 5 is thus supported by the three-point support ball bearing seat 10, the swivel base 5 can freely rotate left and right in 90° steps.

Furthermore, as shown in FIG.
has been established.

Reference numeral 12 denotes a base of the measuring device, on the top of which two guide rails 13 are installed in parallel as shown in FIG. It is placed in 13. Since the movable base 9 is supported by the guide rail 13, the position of the movable base 9 on which the swivel base 5 is mounted is adjusted to the third position.
You can freely change it forward or backward in the diagram.

To explain the operating procedure, the wafer 22 is first positioned at the left end of the moving stage 12 in FIG. 1, and then placed on the guide portion 6a having a diameter corresponding to the diameter of the wafer 22 to be measured as shown in FIG.

Next, move the moving table 9 rightward on the drawing of FIG. 1 to move the center point A of the wafer 22 shown in FIG.
is positioned directly below the upper displacement sensor 25. Once the positions are determined, the measurement positions of the upper and lower displacement sensors 25 and 26 are adjusted appropriately by rotating the pinions 3 of the upper and lower mounting parts, and the measurement positions of the wafer 22 and the upper and lower displacement sensors 25 and 26 are adjusted as appropriate.
Set the gap between the two to an appropriate value. This completes the preparation for measurement.

If the measurement points are five points A to E on the wafer 22 as shown in FIG.

(b) Next, move the moving table 9 to the right in FIG.
, and measure the thickness at point B.

(c) Further, the movable stage 9 is moved to the left in the drawing of FIG. 1, and the thickness of the wafer 22 at the point C is measured by positioning the wafer 22 so that the point C is directly below the upper displacement sensor 25.

(d) Next, move the movable table 9 to the right in the drawing of FIG. 1, position it so that the center point (point A) of the wafer 22 is directly below the upper displacement sensor 25, and then move the swivel table 5 to the right. or 90° to the left
Rotate and measure the thickness at point D and point E, respectively.

(e) Once the thickness measurement at each point is completed, move the movable table 9 to the left end in the drawing of FIG.
The wafer 22 is taken out from the rotating table 5, and the measurement work for the wafer 22 is completed.

In the above, a pair of upper and lower displacement sensors 1, 2
As suitable examples, the pinion 3 and rack 4 are engaged as a mounting means, the three-point ball bearing seat 10 is used as a support for the swivel base 5, and the rail 13 is used as a guide means for the movable base 9. However, the present invention is not limited to these.

[Effects of the invention] As explained above, according to the invention, the wafer can be positioned freely by combining the operations of the rotating table and the moving table, and it is possible to avoid means such as tweezers that cause scratches. In addition, the swivel table can be equipped with guides of several sizes to handle wafers of different sizes, and the thickness can be measured without changing the positional relationship of the wafer itself with respect to the guide surface. (a) Compared to conventional measuring devices, it is possible to significantly reduce the number of measurement steps, resulting in high measurement efficiency.

Measurements can be made without damaging the wafer surface, meeting quality control requirements.

C. Wafers of several sizes can be easily measured without the need for any special equipment or accessories, improving operability and reducing management man-hours.

(2) The entire wafer can be rotated or moved in parallel at all times, greatly improving measurement accuracy and reproducibility.

e) As a result of being easy to operate, no particular skill in operation is required, there is little variation in measured values between operators, and a high level of precision as a measuring device can be obtained.

Therefore, the effects of the present invention are extremely large.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway right side view showing the configuration of an embodiment of the present invention, Fig. 2 is a plan view of the embodiment,
FIG. 3 is a partial cross-sectional view as seen from the front, FIG. 4 is a cross-sectional view of the swivel table and three-point support ball bearing seat with a wafer mounted in the same embodiment, and FIG. A plan view of the bearing seat, FIG. 6 is a diagram showing measurement points on a wafer, FIG. 7 is a side view and a plan view of a conventional example,
FIG. 8 is a side view and a plan view showing another conventional example. 2A...Top mounting part, 2B...Bottom mounting part, 3
...Pinion, 4...Rack, 5...Swivel base, 6
a, 6b, 6c, 6d...Guiding part, 7...Hollow part, 8...Race groove, 9...Moving table, 10...Three-point support ball bearing seat, 11...Race groove, 1
2...Base, 13...Guide rail, 15...Swivel table guide, 21...Surface plate, 22...Wafer, 2
3...Stopper, 24...Three ball seat, 25...Upper displacement sensor, 26...Lower displacement sensor, 27...
ball.

Claims (1)

[Claims for Utility Model Registration] (1) It has a pair of displacement sensors facing each other in the vertical direction, and a wafer is placed between the pair of displacement sensors and the wafer is moved by the pair of displacement sensors without touching the wafer. An apparatus for measuring thickness at each point includes a pair of displacement sensors each supported by a mounting means, and a peripheral portion of the wafer on which wafers of various sizes are placed for thickness measurement by the displacement sensors. a rotatable turning means provided with a plurality of guide parts for support; a linear movement means capable of linearly moving on a plane with the turning means placed thereon; and a guide for sliding and supporting the linear movement means. A wafer thickness measuring stand comprising: a base provided with means; (2) The mounting means for the pair of displacement sensors is one in which a pinion and a rack are meshed together, and each displacement sensor can be slid in the vertical direction by rotating and adjusting the pinion. A wafer thickness measuring table according to claim 1 of the utility model registration claim. (3) The wafer thickness measuring table according to claim 1, wherein the rotating table has a plurality of concentric guide portions provided in a stepped manner. (4) The wafer thickness measuring table according to claim 1, wherein the swivel table is supported by a three-point ball bearing.