JP3404319B2 - Method for measuring surface shape and thickness of semiconductor wafer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a semiconductor for precisely measuring the front surface shape and thickness of the silicon wafer or the like
The present invention relates to a wafer surface shape measuring method and a wafer thickness measuring method.

[0002]

2. Description of the Related Art In general, a silicon wafer, which is a base material for semiconductors, is required to have extremely high flatness in order to prevent defocusing when a circuit pattern is exposed on the surface of the silicon wafer.

The effective area between the wafer maker and the user is FQA (Focal Qu-ality Area).
And the standard of flatness in this region is applied. Specifically, for example, the range of 3 mm from the outer circumference of the silicon wafer is not applicable. That is, generally, the surface of a practically used silicon wafer is polished to a mirror surface, but it is not easy to polish the outer peripheral portion to a uniform flatness, and the range of 3 mm from the outer circumference is , Is out of the scope of the standard.

However, it is expected that the excluded region on the outer periphery will become narrower in the future, and the demand for flatness will become more and more strict. In order to meet such a demand, it is necessary to measure and evaluate the surface shape of the outer peripheral edge portion of the silicon wafer with high accuracy, and set the processing conditions based on this measurement and evaluation.

On the other hand, conventionally, the surface shape of a silicon wafer is measured by, for example, measuring the surface of the silicon wafer 1 in a concentric pattern as shown in FIG.

[0006]

However, such a conventional measuring method has a problem that it is difficult to measure the surface shape of the outer peripheral edge portion 1a of the silicon wafer 1 with high accuracy.

That is, generally, in the polishing processing of the silicon wafer 1, a polishing machine having a mechanism for rotating or revolving the silicon wafer 1 itself is often used, and as a result, the surface shape of the silicon wafer 1 is
The shape is often rotationally symmetric with the center of the silicon wafer 1 as the center. Therefore, the silicon wafer 1
When measuring the surface of the concentric circles, the density of the measured data becomes coarser in the direction where the shape change is large,
It becomes difficult to accurately obtain the surface shape of the outer peripheral edge portion 1a.

The present invention has been made to solve the above conventional problems, and provides a surface shape measuring method and a thickness measuring method for a semiconductor wafer , which can measure the surface shape of a semiconductor wafer with high accuracy. The purpose is to

[0009]

A semiconductor wafer according to claim 1, wherein:
Surface shape measuring method of C is configured to rotatably support the semiconductor wafer, measuring means for measuring a distance to the first surface opposite the one surface of the semiconductor wafer, the semiconductor
It is arranged parallel to one surface of the body wafer and movably toward the center, and while the semiconductor wafer makes one rotation,
In synchronization with the rotation of the semiconductor wafer, the measuring means ,
It is characterized in that the semiconductor wafer is reciprocated a number of times over the outer peripheral edge of the semiconductor wafer to measure the surface shape of the outer peripheral edge of the one surface.

[0010]

According to a second aspect of the present invention, there is provided a first method for measuring a thickness of a semiconductor wafer , wherein the semiconductor wafer is rotatably supported and the distance to the one surface and the other surface is measured so as to face the one surface and the other surface of the semiconductor wafer . And a second measuring means arranged parallel to the semiconductor wafer and movably toward the center, and while the semiconductor wafer makes one rotation, the first and second measuring means are synchronized with the rotation of the semiconductor wafer. The second measuring means is the outer circumference of the semiconductor wafer.
And many times reciprocated across the edge, measuring the surface shape of the outer periphery of the one surface and the other surface, said semiconductor web
It is characterized by measuring the thickness of the ha .

[0012] (Function) In the surface shape measuring method for a semiconductor wafer according to claim 1, half
While the conductor wafer rotates once, by multiple reciprocating measuring means in synchronism with the rotation of the semiconductor wafer, the half
The outer peripheral edge of one surface of the conductor wafer is measured in a zigzag shape.

[0013] In the surface shape measuring method for a semiconductor wafer according to claim 2, while the semiconductor wafer rotates once, the semiconductor c
By multiple reciprocating the first and second measuring means in synchronism with the rotation of the Eha, the outer peripheral edge of one surface and the other surface of the semiconductor wafer is measured in a zigzag shape, the semiconductor wafer on the basis of the data Is measured.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. 1 and 2 are half of the present invention.
1 shows an embodiment of a surface shape measuring method of a conductor wafer , and FIG. 3 shows a surface shape measuring apparatus used in this embodiment. In FIG. 3, reference numeral 11 indicates a rectangular base member whose upper surface is horizontally arranged.

The base member 11 is made of granite. Further, the base member 11 is supported by the support column 15 via the air spring 13, and the influence of disturbance vibration is suppressed. A thin disk 17 made of a silicon wafer is arranged above the upper surface of the base member 11.

The disc 17 is rotatably supported by a support means 19 in one vertical plane. The support means 19 has an annular fixed member 21 and a rotary member 23. The fixing member 21 includes a brushless D (not shown).
A coil for a C motor is built in, and a magnet 25 for a brushless DC motor is built in the rotating member 23, whereby a brushless DC motor is configured.

Inside the rotary member 23, a plurality of support members 27 for supporting the disc 17 at a predetermined angle are arranged. On one side and the other side of the vertical plane containing the disc 17,
The first guide shaft 29 and the second guide shaft 31 are arranged horizontally. First guide shaft 29 and second guide shaft 31
Are arranged parallel to the vertical plane and parallel to each other.

The first guide shaft 29 and the second guide shaft 31 are fixed to the upper surface of the base member 11 via a bracket 33. The first guide shaft 29 and the second guide shaft 31 have a very high straightness. The first guide shaft 29 includes a first guide shaft 29 that moves along the first guide shaft 29.
Slider 35 is arranged.

The first slider 35 is provided with a first measuring means 37 for measuring the distance to one surface of the disc 17. Further, the second guide shaft 31 is provided with a second slider 39 that moves along the second guide shaft 31. A second measuring means 41 for measuring the distance to the other surface of the disc 17 is arranged on the second slider 39.

In this embodiment, non-contact laser displacement gauges are used for the first measuring means 37 and the second measuring means 41. The first slider 35 and the second slider 39 are air slides having a built-in linear motor. In this embodiment, the first guide shaft 29 and the second guide shaft 31, the first slider 35 and the second guide shaft
The same parts are used for the slider 39, the first measuring means 37, and the second measuring means 41, respectively.

In this embodiment, vertical moving means 4 for moving the disc 17 in the vertical direction is provided on both sides of the disc 17 in the radial direction.
3 are arranged. The vertical moving means 43 has a third guide shaft 45 fixed vertically to the upper surface of the base member 11. On the third guide shaft 45, the third slider 4 is attached.
7 is movably arranged, and on the third slider 47,
The fixing member 21 of the supporting means 19 for supporting the disc 17 is connected.

A bracket 47 is attached to the third slider 47.
a is formed, and this bracket 47a is used for the ball screw 4
9 is screwed together. The ball screw 49 is the base member 1
1 is disposed perpendicular to the upper surface of the base member 1 and
It is rotationally driven by a motor 51 fixed to the upper surface of 1. In this embodiment, the upper ends of the third guide shaft 45 and the ball screw 49 are supported by the reinforcing member 53.

Further, in this embodiment, the first measuring means 37 and the second measuring means 41 are positioning means for positioning them on the same axis line which is perpendicular to the vertical plane including the disk 17. A block member 55 is arranged. The block member 55 is fixed to the inner circumference of the rotating member 23. An embodiment of the method for measuring the surface shape of a disc of the present invention using the above-mentioned surface shape measuring apparatus is performed as described below.

That is, in this embodiment, first, as shown in FIG.
And as shown in FIG. 2, the first and second guide shafts 2
First and second sliders 35, 39 along 9, 31
Is moved, and the center P of the measuring portion of the first and second measuring means 37, 41 is located at a position P slightly outside the outer circumference of the disc 17.
Located in 1. In this state, the first measuring means 3
The center P of the measuring unit 7 and the center P of the measuring unit of the second measuring unit 41 are located on the same straight line.

The center P of the measuring portion of the first measuring means 37 and the center P of the measuring portion of the second measuring means 41 are located on a horizontal line H passing through the center of the disc 17. Then, from this state, the disc 17 is rotated, and at the same time, the disc 1 is rotated.
In synchronization with the rotation of 7, the first and second measuring means 37, 4
1 is moved toward the center O of the disc 17.

By the movement of the first and second sliders 35 and 39, the center P of the measuring portion of the first and second measuring means 37 and 41 is moved to the inside of the disc 17 by a predetermined distance L,
When located at the position P2, the first and second sliders 3
5, 39 are moved in the opposite direction, and the first and second measuring means 37, 41 are moved toward the outer side of the disc 17 to the first position P1.

By repeating this reciprocating motion, the surface shape of the outer peripheral edge portion 17A of the disk 17 is measured in a zigzag shape as shown by solid lines K1, K2, K3 and K4 in FIG. The measurement of a part of the circular ring portion on the circular plate 17 is completed when the circular plate 17 rotates once. That is, when the measurement is completed, as shown in FIG. 4, the entire area of the outer peripheral edge portion 17A of the disc 17 is measured in a zigzag shape.

In this embodiment, the disc 17 is rotated once per minute, for example, and the first and second measuring means 37 and 41 are reciprocated 60 times, for example. Further, the movement of the center P of the measuring portion of the first and second measuring means 37 and 41 to the inside of the disc 17 is, for example, a position 0.5 mm away from the FQA shown by the chain double-dashed line in FIG. To be done.

The data thus measured is input to a microcomputer and processed as shown in FIG. 5, for example. That is, in FIG. 5, (a)
Shows the detailed shape of the disk 17 on the one surface 17a side, (b) shows the detailed shape of the disk 17 on the other surface 17b side, and (c) shows the thickness of the disk 17.

The uppermost curves A1, B1 and the thickness C1 correspond to the data obtained in the first measurement locus K1 shown in FIG. 1, and the lowermost curves A2, B2 and the thickness C2 are: This corresponds to the data obtained on the measurement locus K2 next to the first measurement locus K1 shown in FIG. In the method for measuring the surface shape of the semiconductor wafer described above, the first and second measuring means 37, 41 are reciprocated many times in synchronization with the rotation of the disc 17 while the disc 17 makes one revolution. Therefore, it becomes possible to measure the outer peripheral edge portion 17A of the disc 17 in a zigzag shape, and it is possible to measure the surface shape of the outer peripheral edge portion 17A of the disc 17 with high accuracy, easily, and reliably in a short time. You can

Therefore, it becomes easy to set the processing conditions when processing the outer peripheral edge portion 17A of the disk 17 which has been difficult in the past, and the processing accuracy can be improved. Before the exposure of the circular plate 17 made of a silicon wafer, the outer peripheral edge portion 17
The success or failure of the exposure can be easily and surely determined from the evaluation result of A. Further, since the measurement is performed in the radial direction of the circular plate 17, more effective information in the radial direction including the roughness can be obtained.

In the above-described embodiment, an example in which the surface shape of the outer peripheral edge portion 17A of the disc 17 is measured has been described, but as a related technique, for example, as shown in FIG. 6, the annular portion 17B of the disc 17 is shown. Can also be applied to the measurement at any width with respect to, and can also be applied to the measurement at any width with respect to the central portion of the disc 17.

[0033]

Further, in the above-described embodiment, an example in which the disc 17 is supported in a vertical plane has been described, but the present invention is not limited to such an embodiment. For example, the disc 17 may be placed in a horizontal plane. You may make it support and arrange | position the 1st measuring means 37 and the 2nd measuring means 41 on this upper side and the lower side. Furthermore, in the above-described embodiment, an example in which a non-contact laser displacement meter is used for the first measuring means 37 and the second measuring means 41 has been described, but the present invention is not limited to this embodiment. For example, a displacement gauge such as a capacitance type displacement gauge can be used.

Further, in the above-described embodiment, one surface (for example, the main surface) and the other surface (for example, the back surface) of the disk 17 made of a silicon wafer are measured by the first measuring means 37 and the second measuring means 41. Although the measurement example has been described, the present invention is not limited to such an embodiment, and for example, only one surface or the other surface of the disc 17 may be measured.

[0036]

As described above, the semiconductor device of claim 1 is used.
In Eha disc surface shape measuring method, while the semiconductor wafer is rotated 1. Thus a large number of times reciprocating measuring means in synchronism with the rotation of the semiconductor wafer, a semiconductor-way
The outer peripheral edge portion of one surface of the wafer becomes possible to measure in a zigzag shape, it is possible to measure the surface shape of the outer peripheral edge of the semiconductor wafer with high accuracy.

[0037]

[0038] In the surface shape measuring method for a semiconductor wafer according to claim 2, while the semiconductor wafer rotates once, the semiconductor c
By multiple reciprocating the first and second measuring means in synchronism with the rotation of the Eha, one surface and the other surface of the outer peripheral edge portion of the semiconductor wafer is measured in a zigzag manner, the semiconductor wafer on the basis of the data The thickness can be measured, and the thickness of the outer peripheral edge portion of the semiconductor wafer can be measured with high accuracy.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of a semiconductor wafer surface shape measuring method of the present invention.

FIG. 2 is a top view of FIG.

3 is a perspective view showing a surface profile measuring apparatus used in the method for measuring the surface profile of the semiconductor wafer of FIG.

FIG. 4 is an explanatory diagram showing a measurement range in the method for measuring the surface shape of the semiconductor wafer in FIG.

5 is an explanatory diagram showing a state in which data measured by the surface shape measuring method for the semiconductor wafer of FIG. 1 is processed.

FIG. 6 shows a method for measuring the surface shape of a semiconductor wafer according to the present invention.
It is explanatory drawing which shows a related technique .

FIG. 7 is an explanatory diagram showing a conventional measuring method.

[Explanation of symbols]

17 discs 17A outer peripheral portion 17a One side 17b Other side 19 Supporting means 29 First guide shaft 31 Second guide shaft 35 First Slider 37 First Measuring Means 39 Second slider 41 Second measuring means

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-10-246621 (JP, A) JP-A-6-281449 (JP, A) JP-A-8-54204 (JP, A) JP-A-8- 152319 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01B 21/00-21/32

Claims (2)

(57) [Claims] 1. A while rotatably supporting a semiconductor wafer, the measurement means to face one surface of the semiconductor wafer for measuring a distance to said one surface, parallel to the one surface of the semiconductor wafer <br/>, and movably disposed toward the center, while the semiconductor wafer is rotated 1, wherein the semiconductor
It said measuring means in synchronism with the rotation of the wafer, the semiconductor
A surface shape measuring method for a semiconductor wafer , comprising reciprocating a large number of times over the outer peripheral edge of the wafer to measure the surface shape of the outer peripheral edge of the one surface. 2. When a semiconductor wafer is rotatably supported
Both face one side and the other side of the semiconductor wafer.
Measuring the distance to said one side and the other side, and
A second measuring means parallel to the semiconductor wafer, and
The semiconductor wafer is arranged so as to be movable toward the center.
Synchronize with the rotation of the semiconductor wafer during one rotation of c
Then, the first and second measuring means are connected to the semiconductor wafer.
-Move back and forth many times across the outer peripheral edge of the
And measuring the surface shape of the outer peripheral edge of the other surface,
Semiconductors, characterized in that measuring the thickness of a semiconductor wafer
Body wafer thickness measurement method.