JPH03218044A - Standard wafer - Google Patents

Abstract

PURPOSE:To avoid the adherence of any foreign matter to the wafer surface after every measurement by a method wherein a surface protector whereon a transparent film is formed is bonded onto the wafer surface whereon standard particles are bonded. CONSTITUTION:A surface protector 11 comprising a frame body whereon a transparent film 13 is formed is bonded onto a standard wafer 1 on whose mirror wafer 2 standard particles 3 are bonded to protect the surface of the wafer 1 so that any foreign matters may adhere to the surface of the protector 11 not to adhere to the surface of the wafer 1. Accordingly, the measuring light is focussed on the particles 3 of the wafer 1 regardless of the foreign matters while enabling the foreign matters adhering to the protector 11 to be removed easily so that the standard wafer 1 having no foreign matters adhered to the surface at all after every measurement may be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a standard wafer used in calibrating the detection sensitivity of a foreign object inspection device used in a semiconductor manufacturing process.

[Conventional technology]

FIG. 3(a) is an external view showing a conventional standard wafer.

In this figure, 1 is a standard wafer, 2 is a clean mirror wafer constituting this standard wafer 1, and 3 is a standard particle deposited on this mirror wafer 2. Fig. 3(b)
are the output signals when the standard wafer 1 is measured by the scattering type foreign particle inspection device, and 4 is the dot 1 indicating the detected foreign particle (in this case, the standard particle 3).

FIG. 4(a) is an external view showing the standard wafer when it is contaminated; 1 to 3 are the same as in FIG. 3(a), and 5 is a foreign substance attached to the standard wafer 1.

FIG. 4(b) is an output map when the standard wafer 1 in FIG. 4(a) is measured. be.

Next, the operation will be explained. Standard particles 3 (
Boristyrene latex 0.1 to 10 μm, number 10 to 1
When a standard wafer 1 with 0.000 wafers/wafer attached to one half is measured using a foreign matter inspection device (for example, Hitachi Electronic Engineering Co., Ltd. [{LD, LS-5000, former LIS, Tencor Co., Ltd. Surface Scan, etc.]), The standard particle 3 on the mirror wafer 2 is detected and displayed as a dot 4 on the map of FIG. 3(b). At this time, standard wafer 1
If the wafer is in a clean state, the only foreign matter to be detected is the standard particle 3, which appears only on one side of the wafer as shown in FIG. 3(b).

When using it to calibrate the sensitivity of a foreign object inspection device, measure the standard wafer 1 with the sensitivity as a preliminary standard, then remeasure it over time, and if there is a change in the number of particles detected, make sure to match the original number. Adjust the sensitivity of the device.

FIG. 4(a) shows a case where the standard wafer 1 is contaminated, and shows that foreign matter 5 is attached to the standard wafer 1. The output map obtained by measuring this with a foreign particle inspection device is shown in Figure 4 (b), and in addition to the standard particles 3, foreign particles 5 with a size larger than the standard particles 3 are also detected, so not only on one side of the wafer but also on the entire wafer surface. Dots 1-4 are displayed. In this case, even if the sensitivity of the device itself is the same, the number of detections will increase.

[Problem to be solved by the invention]

Since the conventional standard wafer 1 is constructed as described above, if dirt and foreign matter 5 become attached after being used many times, the number of detected particles will decrease even if the same standard wafer 1 is measured with the same sensitivity. As a result, sensitivity calibration based on the number of objects becomes impossible.

Furthermore, if the standard wafer 1 is cleaned or cleaned, the standard particles 3 as well as the foreign matter 5 will be removed.
There were problems such as once contaminated, it could not be regenerated.

This invention was made in order to solve the above-mentioned problems, and no matter how many times the measurement is performed, foreign matter does not adhere to the wafer surface, so the number of detected particles does not change, and the standard particles are removed. The purpose is to obtain a standard wafer from which only foreign matter can be removed.

[Means to solve the problem]

The standard wafer according to the present invention has standard particles attached to a clean wafer surface, and a surface protector on which a transparent film is formed is placed in contact with the wafer surface to protect this surface. It is composed of

[Effect]

The standard wafer in this invention prevents foreign matter from directly adhering to the standard wafer by a surface protector bonded onto the wafer surface. In addition, regarding foreign matter attached directly above the surface protection, since the foreign matter on the standard wafer and the 7-year-old debris are detected together, the surface protection equipment does not detect the foreign matter on the surface protector, and the standard wafer is Washing the protective equipment removes only the foreign matter and does not remove the standard particles.

〔Example〕

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

FIGS. 1(a) and 1(b) are views showing one embodiment of the present invention, where FIG. 1(a) is a perspective view of a surface protector bonded onto the wafer surface, and FIG. 1(b) is a perspective view of a surface protector bonded onto the wafer surface. FIG. 1 is an external view showing a standard wafer to which the surface protector of FIG. 1(a) is attached. In Figure 1, 1 to 3 are the same as in Figures 3 and 4,
Reference numeral 11 indicates the surface protection odor of the present invention, which is composed of a frame 12 and a transparent film 13 attached to one side of the frame 12.

As the transparent M13, a transparent film mainly composed of 21-cellulose is used. However, other polymer compounds may be used as long as the same level of transmittance (90% or more) can be obtained. The film thickness is, for example, approximately 0.8 μm to 6 μm. FIG. 2(a) is an external view of a dirty standard wafer 1, and FIG. 2(b) is a cross-sectional view of FIG. 2(a). Figure 2 (
c) is an output map when a dirty standard wafer 1 is measured by a foreign matter inspection device. 1 to 5 and 11 to 13 in FIG. 2 are the same as those in FIG. 1, FIG. 3, and FIG. 4.

Next, the operation will be explained.

In Figure 1, a clean mirror wafer 2 (for example, a round wafer 0.3
The standard particles 3 were attached to the surface of foreign matter of mφ or more (less than 10 particles/wafer) in a clean environment (class
1 to 100), a surface protector (similar to a pellicle attached to a mask used in the photolithography process) with a transparent film 13 is attached to the frame 12, and a standard A wafer 1 is prepared. When foreign matter adheres to the standard wafer 1, the foreign matter 5 adheres to the transparent film 13 of the surface protector 11 as shown in FIGS. Does not adhere directly, can this be measured with a foreign substance inspection device?
Then, since the focus of the foreign matter inspection device is set on the surface of the Mt wafer 2, the foreign matter 5 attached to the transparent film 13 is not focused and is not detected. In other words, even if foreign matter 5 adheres to the standard wafer 1, only the standard particles 3 in the standard wafer The reliability is increased, and the numbers can be easily compared. Further, handling of the standard wafer 1 is also easy. Furthermore, even if a foreign object 5 large enough to be detected even out of focus adheres to the transparent film 13, only the foreign object 5 can be washed away without removing the standard particles 3, or a blank scrubber (blanket cleaner, etc.) can be used. It can be removed with .

In the above embodiment, the standard particles 3 are attached to the mirror wafer 2 to form the standard wafer 1. However, instead of the mirror wafer 2, %(At', SiO
A wafer with a wafer (si, etc.) or a wafer with a vacuum is used as a standard wafer for a wafer inspection device with a membrane/putter 7.

The following three types of wafers are mainly considered as sensitivity test/substrate wafers for the wafer inspection equipment with film/vacuum.

(i) The film to be measured is deposited on the fi-plane wafer with the desired film thickness, and standard particles are attached on top of it (#
(11) Standard particles are attached to a wafer in a certain process during the fabrication of actual devices (for inspection of wafers with a button) (Ill) A thin film is deposited on a mirror wafer, and a particle of a certain size is deposited on a mirrored wafer. Several types of holes are opened at certain locations (e.g. V
Standard wafer 1420 (manufactured by LSI Standard Inc.) These wafers are similar to the case of mirror-finished wafer 2.If other foreign matter adheres to these wafers, the number of detections increases and it becomes impossible to check the positive F% degree. This problem can be solved by applying the surface protector 11 to the standard wafer 1.

Moreover, although the shape of the frame 12 is preferably circular,
Other shapes are also acceptable.

〔Effect of the invention〕

As explained above, in this invention, a standard wafer is constructed by bonding a surface protector on which a transparent film is formed on the surface of the wafer 1, so that foreign matter does not directly adhere to the wafer surface. , the foreign matter adheres to the transparent ridge of the surface protector. Therefore, when measuring with a foreign matter inspection device, the focus of the foreign matter inspection device is on the wafer surface, so the foreign matter on the transparent crotch is not detected and the wafer Only standard particles attached to the surface are detected. Therefore, no matter how many times the same wafer is used over a long period of time, the number of detected particles remains constant, increasing the reliability of the calibration of the foreign particle inspection device, and making the calibration easy by simply comparing the number of particles. Furthermore, handling becomes easier because it is not necessary to be as careful as in the past regarding foreign matter adhering to the wafer.

In addition, even if a large amount of foreign matter or a large amount of foreign matter adheres to the transparent film, it is possible to remove only the foreign matter without removing the standard particles, making it possible to efficiently use standard Ueno. It will be done.

[Brief explanation of drawings]

FIG. 1(a) is an external perspective view of a protective device showing an embodiment of the present invention, FIG. 1(b) is a view of the protective device of FIG. 1(a) glued together, FIG. 2(a) 2(b) is a sectional view of FIG. 2(a); FIG. 2(C) is a diagram showing an output map during measurement;
FIG. 3(a) is an external perspective view showing a conventional standard wafer, FIG. 3(bl) is a diagram showing an output map when measuring a conventional standard wafer, and FIG. Fig. 4(b) is a perspective view of the external appearance when foreign matter is attached to the wafer, and Fig. 4(b) is a diagram showing the output map during measurement. is a dot, 5 is a foreign object, 11 is a surface protector, 1
2 is a frame body, and 13 is a transparent film. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A standard wafer comprising: a surface protector having a transparent film formed thereon adhered to the wafer surface to protect the wafer surface to which standard particles are attached.