JPS5921024A - Inspecting device for photo-mask - Google Patents

Abstract

PURPOSE:To discover a pattern chipping, a data missing, a common defect, etc. easily by providing means, which can change the magnification of observation of the photo-mask mutually independently, and comparing and inspecting parts of different magnification such as a reticle and a master. CONSTITUTION:The photo-mask 11 prepared is placed on a right measuring base, and the reticle 12 is placed on a left measuring base. Beams from a light source 2 are transmitted and illuminated from the upper sections of the master mask 11 and the reticle 12 in illumination. Objectives are given variable power functions, the magnification of the right objective 3a is made the same as conventional one, and the magnification of a left variable power lens 6 is made one tenth as large as right magnification. An image having the same magnification as the image of the master mask 11 is obtained by the variable power lens 6 regarding the image of the reticle 12 having magnitude decuple as large as the image of the master mask 11. The images having the same magnification acquired in this manner are conformed through prisms, etc. The magnification of a conformed image is changed by a variable power lens 4, an output from the image reaches eyepieces 5a, 5b, and the mutually different photo-masks can be observed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for comparatively inspecting ζ photomasks with different magnifications. Recently, there has been an increasing demand for high-precision white clay for photomasks.

An example of a conventional glaze photomask inspection apparatus is schematically shown in FIG. 1 and will be described. In the figure, 0a).

(1b) is the prepared photomask, and the photomasks (la) and (lb) are placed on the soil of a measurement stand (not shown), and the light from the light source (2) is transmitted and illuminated from the top of the photomask. Then, this transmitted light weight 1 is passed through objective lenses (3a) and (3b) installed under the measuring table, respectively.
The optical path is changed using a prism, etc. to match the transmitted images. The matched image has its magnification changed by 9 times through a variable magnification lens (4), and its output is sent to an eyepiece (5a).

(5b) is configured so that it can be observed.

However, in such a photomask inspection device, the left and right photomasks (1m) and (lb) must have the same magnification υ, and it is impossible to measure photomasks with different magnifications. It was possible. Therefore, it has the disadvantage that, for example, it is impossible to perform a comparative inspection between a 1x master mask and a 10x reticle.

On the other hand, recently, it has become possible to easily and accurately produce master masks and reticles of various magnifications using electron beam exposure equipment. 1. A master mask is created from a photorepeater with great precision.

However, comparative inspection of photomasks with the same magnification is the first step.
Although this was possible with the apparatus shown in the figure, it was impossible to perform a comparative inspection of the first masks (with different h4 ratios), and there was no effective inspection means available. Therefore, when creating a redicle for use in a wafer stepper, etc.,
There was no guarantee that it would match the pattern theta.

In addition, in conventional inspection methods, an artificial observation operation such as observation using a microscope is required, which requires the measurement and inspection of a large number of photomasks, which requires an extremely large amount of labor and time. There is a drawback.

In view of the above points, the present invention has been made in order to solve such problems and eliminate such drawbacks. .

To provide a photomask inspection device that can easily detect missing data, common defects, etc., and that can easily perform inspections that conventionally took a long time using a human microscope in a short time. be.

In order to achieve such an object, the present invention includes means for changing the observation magnification of the seven otomasks independently of each other,
The present invention is designed to enable comparative inspection of masks with different magnifications, such as a reticle and a master.Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a block diagram schematically showing an embodiment of a photomask inspection apparatus according to the present invention, and only the parts necessary for explanation are shown.

In Fig. 2, the same numbers as in Fig. 1 indicate corresponding parts, θυ is the photomask (master mask) placed on the measurement table on the right side, (13 is the reticle placed on the measurement table on the left side) , (6) is the objective lens (variable magnification lens) inserted into the optical path system of reticle Q21.
For example, the objective lens (3a) on the right side has a variable magnification function with a magnification of 1/□0.

Next, the operation of the embodiment shown in FIG. 2 will be explained. First, the created photomask (master mask) aυ is placed on the right measuring table, and the reticle a3 is placed on the left measuring table. As for illumination, the light from the light source (2) is transmitted through the upper part of the master mask Ov and the reticle H, as in the case of FIG. 1 described above. The transmitted image obtained by passing through this master mask aυ and reticle a21 is the objective lens (3a) and the variable magnification lens (6
), but here, as mentioned above, this objective lens has a variable magnification function, and the right objective lens (3a
) has the conventional magnification, and the variable magnification lens (6) on the left has a magnification of 1/1° of the magnification on the right. The image of the reticle Q4, which is 10 times the size of the image of the master mask 0υ, is obtained by the variable magnification lens (6) (objective lens) with the same magnification as the image of the master mask 0υ.

The images of the same magnification obtained in this way are provided with a prism or the like to match the images. The matched image changes its magnification through the variable magnification lens (4), and its output is sent to the eyepiece (5a) #
Until (5b), different photomasks can be observed.

In addition, in the conventional method, since the photomask with the same magnification was observed, it was sufficient to move the left and right measurement tables at the same time.
In the embodiment shown in FIG. 2, since the magnifications of the left and right photomasks are different, the measurement table must move independently on the left and right sides and in accordance with the magnification (in this embodiment).

In this way, a comparative inspection of a reticle with a magnification of 1/1o and a master mask with a magnification of 1x can be performed independently or with L2
Variable magnification possible ifs lens (6) (objective l/lens)
,! The stage can be operated independently [,2, and at a rate of 31 Furthermore, since the pickle is used as oil, it is easy to find holes, missing patterns, missing data, and common defects.
Inspections that used to take a long time due to manual observation using a microscope now become easier and shorter? '7' is over.

FIG. 3 is a schematic diagram showing another embodiment of the present invention;
Only the parts that are cheap to F15 and Akira are shown.

In this figure 3, the same part as ``C2〆j is
” and omit the explanation.

(3b) is the objective lens inserted into the optical path thread of Retekno L (1:!J), (7Jij, installed in the front stage of this objective lens (3b) &ff1il small lens (modified false 1 nons)
So, the variable magnification lens (7) is attached to the reticle (on the measuring stand on the left side where 121 is mounted).
,! ) Ll-zot) Reduction rates r, l, 'Ao.

(Created as shown in 2) C1 - First, create h/c - Master mask 0
Place the υ on the measuring stand on the 4th side, and place the reticle (L2J) on the soil of the measuring stand on the /l- side. reduction l/ns) (
In this case, if the reduction rate is 1/i0), then 1//l
19 Therefore, an image similar to the master mask (lυ) appears on each pair of proboscises (lυ). (3a),
The images are matched via (3b). .

In steps 1 to 1, the magnification of the matched image is changed by the variable magnification lens (4), as in the case of second step 1. , the outputs reach the eyepiece lenses (5a) and (5b), allowing observation of photomasks with different magnifications.

This makes it easy to compare and inspect photomasks with different 4M ratios. 4. Figure 4 is a small block diagram schematically showing still another embodiment of the present invention, and shows only the parts necessary for explanation. Only shown.

In the apparatus of the embodiment shown in Fig. 2, it was necessary for the measuring table to move independently to the left and also in proportion to the magnification, but in the case of the measuring table shown in Fig. 4, The movement is the same as the conventional one, and the fins are designed to be easy to detect. .

j in Figure 4, t41 with the same symbol as Figure 3
The corresponding parts are shown 1. -1 (J3ni reticle with a magnification of 10x, (143 is the master mask. -fL, image formed into a primem shape by the variable magnification lens (7) (reduction lens) and the master mask (Since the image formed in 1, 1 and 1 is formed on the same plane, observation is easy, and the movement of the 6111 fixed table can be the same as that of the conventional one. -FReporter In the embodiment, a case was explained in which a variable magnification lens (objective lens (6) and reduction lens (7j) were installed after light entered the photomask that is the measurement object, but the present invention However, the present invention is not limited to this, but each of these variable magnification lenses may be installed before light enters the photomask so that the observation magnification can be changed independently from each other, and the function can be formed to form an image on the photomask surface. In addition, in each of the above embodiments, the objective lens (
3b) before entering the light, a variable magnification lens (objective lens (61,
Although the explanation has been given by taking as an example the case where a lens (7)) is installed, the present invention is not limited to this, and each of these variable magnification lenses is installed after the light enters the objective lens (3b). It is also possible to have a function that allows observation magnification to be changed independently of each other.

Furthermore, in each of the embodiments, the case of a 10x magnification and a 1x master mask was explained as an example, but the present invention is not limited to this, and may be applied to other magnifications. , for example, a 5-buddha reticle may be used, and the same effect can be achieved.

As is clear from the above description, the present invention has a simple structure that includes means for changing observation magnifications of photomasks independently of each other without using complicated means. Inspection can be carried out, and patterns such as missing data, data omissions, and common defects can be easily discovered, so the practical effect is extremely large. Furthermore, since the present invention eliminates the need to rely on manual observation operations as in the past, all kinds of inconveniences caused by this can be solved, and manual microscopic observation takes a long time. It is also extremely effective in that an inspection that previously required +1jj can be performed easily and in a short time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram schematically showing an example of a conventional photomask inspection device, FIG. 2 is a block diagram schematically showing an embodiment of a photomask inspection device according to the present invention, and FIG. 3 is a block diagram schematically showing an example of a photomask inspection device according to the present invention. FIG. 4 is a block diagram schematically showing another embodiment of the present invention. (21... Light source, (3m), (3b)... Objective lens, (4)... Variable magnification lens, (5a), (5
b)...eyepiece, (6)...variable magnification lens (
objective lens), (71... variable magnification lens (reducing lens), aIJ... photomask (master mask),
(l Enoki, 03... reticle, 01, Moe - photomask (master mask). Agent Haku Kuzuno - (11) Figure 3, Company 4 F; Yo\◇ 1 Asa Juryoku, correction book (Voluntary) 1975/1) Passed away (11) Mr. Commissioner of the Patent Office 1! J<f! Table of l-21, holding (l 1985
-132757 No. 2, Issued November (]) N1.
(Photomask inspection equipment 3 supplementary IF) Relationship 1. ? , f'+ Applicant Representative Ministry Kata Yuhito 8th Division 4, Herijin 5, Subject of Amendment + 1. l Column for detailed explanation of the invention in the specification (2)
IYl) Single explanation column 64 of the drawings in the specification Inner boundary of amendment fil Specification 1 Page 7 Lines 16 and 18 1-
(2) Correct "reduction - 1" in lines 3 and 4 of No. 8M of the same Ministry to "1 - reduction."
"Reduction" is corrected. (3) What is the image formed by 1 (reducing lens) on page 9, lines 4 to 5 of the same book?” to “The image formed by (reducing lens) is the master mask (141 ”. (4) “Reduced by 1” in lines 10 and 17 of the same page on the same page.”
"Reduction" is corrected. (5) Correct "1 reduction - 1 in the 11th negative line of the same book by 1." Below

Claims (3)

[Claims] (1) Place first and second masks with different magnifications on the measurement table, and transmit the light from the light source from the side of the photomask F to the photomask.
, The optical path of the fc light is changed by a prism etc. through an objective lens to match each transmitted image, and this matching 1 to
A photomask inspection device for changing the magnification of an image using a variable magnification lens and observing it through an eyepiece, further comprising means for independently changing the observation magnification of the photomask. Features of photomask inspection equipment. (2) As a means for independently changing the observation magnification of the photomasks, a variable magnification lens is installed before or after the light enters the photomask, and the observation magnification is changed independently. 1 [4] The first claim is characterized in that it is capable of forming an image on the first mask surface 7 JJ
it-: photomask inspection device. (3) As a means to independently change the observation magnification of the photomask, a variable magnification lens is installed after the Mf + that enters the objective lens or after the observation magnification. 1. A first mask inspection apparatus according to claim 1, wherein the mask inspection apparatus is configured such that the mask inspection apparatus can vary.