JPS62206433A - Substrate for inspection - Google Patents

Abstract

PURPOSE:To obtain a substrate for inspection forming a mimic foreign matter free from deformation by cleaning or the like, by providing a substrate having a part worked in a concave or convex on the surface thereof by etching while a thin film pattern and a reflecting film are formed thereon. CONSTITUTION:A substrate 13 for inspection includes a substrate 15 having a part 14 worked in a concave by etching, a thin film pattern 16 only formed on the topmost surface 15a of the substrate 15 and a reflecting film 17 formed on the thin film pattern 16 and on an exposed surface 14a within the part 14 worked in a concave thereof 15. The substrate 15 made of soda lime glass, the thin film pattern 16, of chromium and the reflecting film 17, of tantalum. In addition, the substrate for inspection has a concave pattern 18 with a shape corresponding to the part 14 worked in a concave. This concave pattern 18 serves as mimic foreign matter which scatters a laser light 2 irradiated from a laser light source 1 of a substrate surface inspector.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to inspection substrates, and in particular, to inspection of the number and size of foreign particles present on substrates such as photomask blanks and silicon wafers. The present invention relates to an inspection substrate suitable for use as a detection signal calibration substrate of a substrate surface inspection device.

[Conventional technology]

Substrates such as photomask blanks and silicon wafers used in semiconductor device manufacturing processes are required to be of high quality and free from foreign matter such as dust and minute defects such as scratches on the surface of the substrate.

Therefore, in order to inspect the number, size, etc. of minute defects on the substrate surface, a substrate surface inspection apparatus using, for example, a laser beam is used. As shown in FIG. 5, this substrate surface inspection apparatus emits a laser beam 2 from a laser light source 1 to a substrate to be inspected.
The light receiving device 6 detects the scattered laser light 5 scattered by the foreign matter 4 present on the surface. The light amount of the laser scattered light 5 corresponds to the size of the foreign object 4, and the magnitude of the detection signal generated from the light receiving device 6 that detected the laser scattered light 5 also corresponds to the size of the foreign object 4. That is, the sharpness of the detection signal generated from the light receiving device 6 that detects the laser scattered light 5 scattered by a foreign object 4 of a predetermined size (e.g., spherical dust with a diameter of 1 μm) also corresponds to the size of the foreign object 4. It becomes a predetermined value. However, in different substrate surface inspection devices, this predetermined value differs due to differences in the characteristics of the light receiving device 6, and even in the same substrate surface inspection device, this predetermined value differs due to changes in the usage environment, etc. come. Therefore, it is necessary to select and determine a predetermined value corresponding to a foreign substance of a predetermined size in different board surface inspection equipment, or to select and decide a predetermined value in the same board surface inspection equipment when the usage environment changes, etc. This is necessary.

In order to select and determine this predetermined value, for example, a diameter of 1 μm
A detection signal calibration substrate is used that has a pseudo foreign object formed thereon that generates a detection signal corresponding to spherical dust particles. Then, using this detection signal calibration board, predetermined values in each of the above-mentioned cases are selected and determined, and the board surface inspection apparatus is calibrated.

Conventionally, as a detection signal calibration board, Figs. 6(a) to (e)
) is used. In other words, a positive photoresist on the silicon substrate 7]
8 is applied (FIG. 6(a)), and then UV light 10 is exposed from above the positive type photoresist 8 through an exposure mask 9 to obtain a desired pattern (FIG. 6(b)).
. Next, the exposed portion of the positive photoresist 8 is removed by developing with a developer, and a resist pattern 11 consisting of the unexposed portion is formed on the silicon substrate 7 (FIG. 6(C)).

Next, using an etching solution suitable for the silicon substrate 7, the portion of the silicon substrate 7 exposed from the resist pattern 11 is etched to form a silicon substrate 7' (FIG. 6(d)). Next, the resist pattern 11 is peeled off using a stripping solution to form a silicon pattern 7a as a pseudo foreign substance on the silicon substrate 7' (FIG. 6(e)).

As described above, a detection signal calibration substrate 12 having a silicon pattern 7a formed on a silicon substrate 7' as shown in FIG. 6(f) was manufactured and used as a test substrate.

[Problem that the invention seeks to solve]

However, since the detection signal calibration substrate 12 consisting of the silicon substrate 7' and the silicon pattern 7a is made of silicon crystal, it has the disadvantage that it is extremely fragile due to its crystal structure. Therefore, especially when cleaning the detection signal calibration substrate 12 by a scrub cleaning method in which the object to be cleaned is cleaned using a cleaning brush or the like, the detection signal calibration substrate 12 is easily damaged.

Further, since the detection signal calibration substrate 12' made of silicon crystal is easily oxidized, the shape and size of the silicon pattern 7a formed as a pseudo foreign object are also likely to change due to oxidation. When the shape and size of the silicon pattern 7a change in this way, the amount of laser scattered light 5 scattered from the silicon pattern 7a also changes, and the light receiving device 6
The detection signal generated in this case also changes. That is, in the detection signal calibration substrate 12 on which a silicon pattern 7a is formed as a pseudo foreign substance that generates a detection signal corresponding to spherical dust particles having a diameter of 1 μm, for example, the silicon pattern 7a whose shape and size have changed due to oxidation has a diameter A detection signal corresponding to spherical dust particles of 1 μm cannot be generated. As described above, it is not possible to accurately calibrate a substrate surface inspection device using a detection signal calibration substrate that has a silicon pattern whose shape and size have changed due to oxidation. Cannot be used as a test board.

51 The present invention has been made in view of the above-mentioned circumstances, and aims to provide an inspection substrate that is not easily damaged during cleaning, etc., and has pseudo foreign matter formed thereon that does not change in shape or size. purpose.

[Means for solving problems]

The present invention has been made to achieve the above-mentioned objects, and provides a substrate having a concave or convex portion formed on the surface thereof by etching, and a substrate that is resistant to etching and that is resistant to etching. The inspection substrate is characterized by comprising a thin film pattern formed only on the uppermost surface of the substrate, and a reflective film formed on the thin film pattern and on the exposed surface of the substrate.

[For production]

In the inspection substrate of the present invention, the substrate has a thin film resistant to etching, and the thin film has a substrate resistant to etching.

〔Example〕

FIG. 1 is a perspective view showing a test board according to an embodiment of the present invention, and FIG. 2 is a sectional view showing each culm of the method for manufacturing the test board according to the same embodiment.

A test substrate 13 according to an embodiment of the present invention is shown in FIG.

As shown in FIGS. 2(f) and 2(0), there is a substrate 15 having a concave portion 14 (see FIG. 2(f)) formed on the surface of the substrate by etching, and the outermost portion of the substrate 15. A thin film pattern 16 formed only on the upper surface 15a, and a concave portion 1 on the thin film pattern 16 and on the substrate 15.
4, and a reflective film 17 formed on the exposed surface 14a of the inside. Note that the substrate 15 is made of soda lime glass, the thin film pattern 16 is made of chromium, and the reflective film 11 is made of tantalum. Furthermore, this inspection substrate 13 is provided with a concave pattern 18 having a shape corresponding to the concavely processed portion 14, and this concave pattern 18 is exposed to the laser beam irradiated from the laser light source 1 of the substrate surface inspection apparatus described above. It becomes a pseudo foreign object that scatters.

Next, a method for manufacturing the test substrate 13 will be explained using FIG. 2.

First, measure the soda lime glass to the specified dimensions (e.g. 5x5xO
, 09 inches), the amphibatic surfaces of this soda lime glass are polished, washed with pure water, isopropyl alcohol, etc., and dried to obtain a substrate 19 made of soda lime glass. A thin film 20 (thickness: 1000 mm) of chromium is deposited on the surface of this substrate 19 by sputtering.
Next, on the thin film 20, a positive photoresist 21 (for example, Ml" 135 manufactured by Silapray) is formed.
0. A film thickness of 5,000 ml was applied by a spin code method (FIG. 2(a)). Note that the thin film 20 made of chromium
is not etched by the substrate 19 etching means described later. That is, the thin film 20 is resistant to etching of the substrate 19. Next, in order to obtain a predetermined pattern, the positive type resists 1 to 21 are exposed through an exposure mask 22.
Far ultraviolet light or ultraviolet light 23 (wavelength: 200~
450 nm) (Fig. 2(b)). Next, the exposed portion of the positive photoresist 21 is removed by developing with a developing solution (e.g., Developer for HP-1350) for a predetermined period of time (e.g., 70 seconds), and the resist pattern 24 consisting of the unexposed portion is formed into a thin film. 20 (Fig. 2 (C)
)).

Next, apply an etching solution suitable for the thin film 20 (e.g. nitric acid dichloromethane).
Etching is performed for a predetermined time (for example, 40 seconds) using a mixed aqueous solution of cerium ammonium and perchloric acid to form a thin film pattern 16 (FIG. 2(d)). At this time, the substrate 19 is not etched with the etching solution suitable for the thin film 20. Next, the resist pattern 24 is peeled off using a stripping solution (e.g. hot concentrated sulfuric acid at 90° C.), then immersed in sulfuric acid at room temperature to lower the temperature, and then soaked in water.

A thin film pattern 16 is formed on the substrate 19 by ultrasonic cleaning in isopropyl alcohol and drying in Freon vapor (FIG. 2(e)).

Next, a substrate etching liquid (e.g., a mixed solution of hydrofluoric acid and ammonium fluoride aqueous solution) corresponding to the substrate 19 is applied.
By etching the exposed portion of the substrate 19 for a predetermined time (for example, 3 minutes) using an etching method, a concave portion 14 is formed on the surface of the substrate 19, and the substrate 15 is manufactured.

At this time, the thin film pattern 1 is formed only on the uppermost surface 15a of the substrate 15.
6 will be formed. (Figure 2(f)). Also,
The thin film pattern 16 is not etched with a substrate etching solution suitable for the substrate 19. Next, thin film pattern 1
A reflective film 17 (thickness: 100 mm) made of tantalum having reflective and light-shielding properties is deposited on the exposed surface 14a of the concave portion 14 of the substrate 15 by sputtering. , a concave pattern 18 having a shape corresponding to the portion 14 is formed to manufacture the test substrate 13 (FIG. 2(g)). This concave pattern 18 acts as a pseudo foreign object on the inspection substrate 13.

According to the test board 13 of this embodiment, this test board 1
3 comprises a substrate 15 made of soda lime glass, and a reflective film 17 formed on the thin film pattern 16 and on the exposed surface 14a of the substrate 15 to cover the substrate 15.
The test substrate 13 is not easily damaged during cleaning or the like. Furthermore, since this inspection substrate 13 is not easily susceptible to chemical changes such as oxidation, the shape and size of the concave pattern 18 as a pseudo foreign object is also extremely difficult to change. Therefore, this inspection substrate 13 is particularly suitable for use as a detection signal calibration substrate of the above-mentioned substrate surface inspection apparatus. Note that this test substrate 13 is particularly suitable for use as a detection signal calibration substrate, but it goes without saying that it may be used for other purposes.

The present invention is not limited to the embodiments described above.

The pseudo foreign matter may be a convex pattern 25, as shown in FIGS. 3(a) and 3(b), in addition to the concave pattern 18 shown in the embodiment. In this case, the inspection substrate 26 includes a substrate 28 having a convex portion 27 formed on the surface of the substrate by etching, and a top surface 2 of the substrate 28.
The thin film pattern 29 is formed only on the thin film pattern 8a, and the reflective film 30 is formed on the thin film pattern 29 and on the exposed surface 28b of the substrate 28. Then, a portion of the reflective film 30 that covers the convexly processed portion 27 and the thin film pattern 29 formed only on the uppermost surface 28a of the substrate 28 forms a convex pattern 25.

Further, in the embodiment, a thin film 20 is provided on one main surface of the substrate 19.
A positive photoresist 21 is formed on the thin film 20.
First, a positive photoresist 21 is directly applied onto one main surface of the substrate 19, and then this positive photoresist 21 is exposed and developed to form a thin film as shown in FIG. A resist pattern 21a having a shape is formed, and then the substrate 19 is etched to form a concave portion 14 on the surface.
The inspection substrate 32 having the concave pattern 18 serving as a pseudo foreign object may be manufactured by manufacturing the substrate 31 having the above-mentioned structure, and then depositing the reflective film 17 thereon.

In this embodiment, the substrate 19 is made of soda lime glass, but it may be made of materials such as aluminosilicate glass, quartz glass, aluminum, etc., and its size and shape may be determined as necessary. Although the thin film 20 is formed using chromium as a film-forming material, it may be made of any material that is resistant to etching of the substrate 19, such as titanium or aluminum.

The film may be formed by appropriately selecting a film forming material from silicon, tungsten, tantalum, aluminum, molybdenum, etc., or their oxides, nitrides, carbides, borides, etc. Furthermore, although a mixed aqueous solution of ceric ammonium nitrate and perchloric acid was used as the etching solution for the thin film 20 made of chromium, if another film-forming material was selected as the film-forming material for the thin film 20, An etching solution compatible with the film forming material may be used. Furthermore, a thin film different from thin film 20 may be interposed between one main surface of substrate 19 and thin film 20. In addition, if a reflective film is deposited from chromium, an inspection substrate is manufactured through a prescribed process, and the substrate surface inspection device is calibrated using this as a detection signal calibration substrate, it is possible to eliminate the presence of particles on the chromium film. The board surface can be properly inspected for foreign substances and the like.

In addition, as a method for forming the thin film 20 and the reflective film 11, other than the sputtering method, a vacuum evaporation method or an ion blasting method may be used. The resist may be a type photoresist, a positive type or a negative type electron beam resist, and a coating method such as a roll coating method may be used as the resist coating method. Further, as the exposure method, an exposure method using X-rays, electron beams, etc. may be adopted. As the etching method, in addition to the wet etching method employed in the examples, a dry etching method such as a sputter etching method or a plasma etching method may be employed.

〔Effect of the invention〕

According to the test board of the present invention, this test board.

is not easily damaged, and furthermore, the shape and size of the concave or convex pattern as a pseudo foreign object is extremely difficult to change. Therefore, especially when this inspection substrate is used as a detection signal calibration substrate of a substrate surface inspection device, the substrate surface inspection device can always be calibrated with high precision.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a perspective view showing a test board according to an embodiment of the present invention, and FIG. 2 is a perspective view of a test board manufacturing method according to the same embodiment.
FIG. 3 is a cross-sectional view showing the culm, and FIG. 3 is a diagram showing a test board according to a modification of the embodiment. FIG. 3A is a perspective view showing the test board, and FIG. FIG. 4 is a cross-sectional view showing an inspection board according to a modified example of the embodiment, and FIG.
The figure shows a state in which the surface of a substrate to be inspected is inspected using a substrate surface inspection device, and FIGS. 6(a) to 6(e) show various methods of manufacturing a detection signal calibration substrate as a conventional inspection substrate. A sectional view showing the process and FIG. 6(f) are a perspective view showing a conventional test board. 13.26.32... Inspection substrate, 14... Concavely processed portion, 14a, 28b --- Exposed surface,
15゜31...Substrate having a concave portion,
15a, 28a, 31a...the top surface of the substrate,
16.29... Thin film pattern, 17.30... Reflective film, 18... Concave pattern, 21a... Thin film resist pattern, 25... Convex pattern, 27...
Convexly processed portion, 28...Substrate having a convexly processed portion

Claims (1)

[Claims] (1) A substrate having a concave or convex portion on the surface of the substrate by etching, a thin film pattern that is resistant to etching of the substrate and formed only on the uppermost surface of the substrate, and the thin film. An inspection substrate comprising a reflective film formed on the pattern and on the exposed surface of the substrate.