CN108732870B - Method for measuring input reproducibility of silicon wafer - Google Patents

Abstract

The invention discloses a method for measuring the input reproducibility of a silicon wafer, which avoids the contact of a test silicon wafer with a liquid immersion area by adjusting the measuring position and the setting position of a test mark, and achieves the aim of not coating a waterproof coating on the test silicon wafer. The technical scheme of the invention avoids the loss of the test mark on the silicon chip, improves the measurement accuracy and prolongs the service life of the test silicon chip.

Description

Method for measuring input reproducibility of silicon wafer

Technical Field

The invention relates to the field of debugging of photoetching machines, in particular to a method for measuring the input reproducibility of a silicon wafer.

Background

With the development of microelectronic technology, the use of liquid immersion lithography machines is increasingly frequent. During the photolithography operation of the immersion lithography machine, various performances of the immersion lithography machine need to be tested to ensure the precision of the lithography process. The stability requirement of the silicon wafer at the conveying position in the conveying system is high, so that the silicon wafer input reproducibility of the liquid immersion lithography machine needs to be tested, and the silicon wafer can be conveyed to the designated position in the lithography process without position deviation.

In the existing method for measuring the input reproducibility of the silicon wafer, the test silicon wafer is contacted with liquid immersion water due to the liquid immersion water in a photoetching projection area of a liquid immersion photoetching machine. In order to prevent the liquid from leaking laterally after soaking, a waterproof coating needs to be coated on the test silicon wafer before each measurement, and the waterproof coating needs to be removed by wet cleaning after the measurement is finished. However, in the existing test scheme, because the test silicon wafer needs to be repeatedly measured for many times to obtain the reproducibility data, the measurement times are more than 30 times, so that the soaking time of the waterproof coating contacting the liquid is long, the waterproof coating is easy to peel off, and further the liquid soaking nozzle is blocked. Meanwhile, after each measurement, the reference silicon wafer needs to be cleaned by a wet method to remove the waterproof coating, so that the etched alignment marks on the silicon wafer are lost, the measurement accuracy is reduced, and the service life of the test silicon wafer is shortened.

As shown in fig. 2, the test silicon wafer 1 is in contact with the liquid immersion area 3, the mark area 5 for measurement by the measurement lens is disposed in the middle of the test silicon wafer 1, and the test silicon wafer 1 is inevitably in contact with the liquid immersion area 3 in the projection area 4 due to the fixed position of the measurement lens, which results in the above-mentioned defects in the conventional test scheme.

Disclosure of Invention

In view of the above problems in the prior art, a method for measuring silicon wafer input reproducibility is provided.

The specific technical scheme is as follows:

a method for measuring the input reproducibility of a silicon wafer is applied to a liquid immersion lithography machine and comprises the following steps:

step S1: providing a test silicon wafer, and arranging a test mark on the test silicon wafer;

step S2: placing the test silicon wafer in a conveying system of the liquid immersion lithography machine;

step S3: the test silicon wafer is conveyed to a measuring position by adopting the conveying system, and the test silicon wafer positioned at the measuring position is not contacted with a liquid immersion area of the liquid immersion lithography machine;

step S4: measuring the position of the test mark by using a mark measuring device to obtain a group of test data;

step S5: moving the test silicon wafer out of the measuring position by adopting the conveying system;

step S6: judging whether the quantity of the test data meets the preset required quantity or not;

if yes, go to step S7; if not, returning to the step S3;

step S7: and calculating all the test data to obtain the test result of the silicon chip input reproducibility.

Preferably, the liquid immersion area is arranged in the middle of a projection area of the liquid immersion lithography machine.

Preferably, the measurement position and the projection area are located on the same plane.

Preferably, the test silicon wafer located at the measurement position and the projection area overlap each other.

Preferably, the test mark is arranged on one side of the test silicon wafer close to the soaking area when the test silicon wafer is located at the measuring position.

Preferably, in step S4, the mark measuring apparatus includes a measuring lens, and the measuring lens tests the mark area of the test silicon wafer.

Preferably, the marking region is a square region.

Preferably, the test mark comprises a plurality of mark points.

Preferably, each of the marking points is disposed within the marking region.

Preferably, the test data is the offset of the test mark from the standard position;

in step S7, calculating an average value of the test data is adopted to obtain the test result.

The technical scheme has the following advantages or beneficial effects:

the measuring position and the setting position of the test mark are adjusted to prevent the test silicon wafer from contacting with a liquid immersion area, so that the aim of coating a waterproof coating on the test silicon wafer is fulfilled, the test mark on the silicon wafer is prevented from being worn, the measuring accuracy is improved, and the service life of the test silicon wafer is prolonged.

Drawings

Embodiments of the present invention will now be described more fully hereinafter with reference to the accompanying drawings. The drawings are, however, to be regarded as illustrative and explanatory only and are not restrictive of the scope of the invention.

FIG. 1 is a flow chart of an embodiment of a method of measuring silicon wafer launch reproducibility according to the present invention;

FIG. 2 is a schematic plan view of a prior art silicon wafer launch reproducibility test;

FIG. 3 is a schematic plan view illustrating an embodiment of a method for measuring silicon wafer input reproducibility according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.

In a preferred embodiment of the present invention, as shown in FIG. 1, a method for measuring the reproducibility of silicon wafer input is applied to an immersion lithography machine, and comprises the following steps:

step S1: providing a test silicon wafer, and setting a test mark on the test silicon wafer;

step S2: placing a test silicon wafer in a conveying system of a liquid immersion lithography machine;

step S3: a conveying system is adopted to convey the test silicon wafer to a measuring position, and the test silicon wafer positioned at the measuring position is not contacted with a liquid immersion area of the liquid immersion lithography machine;

step S4: measuring the position of the test mark by using a mark measuring device to obtain a group of test data;

step S5: moving the test silicon wafer out of the measuring position by adopting a conveying system;

step S6: judging whether the quantity of the test data meets the preset required quantity or not;

if yes, go to step S7; if not, returning to the step S3;

step S7: and calculating all the test data to obtain the test result of the silicon chip input reproducibility.

Specifically, in this embodiment, a transmission system is adopted to transmit a test silicon wafer, a test mark on the test silicon wafer is measured at a specified position, so as to obtain test data, and a test result of silicon wafer input reproducibility is finally obtained by calculating data of multiple tests.

The setting of the measuring position is adopted to control the test silicon wafer not to contact with the liquid immersion area, so that the waterproof coating is prevented from being arranged on the test silicon wafer, and the test efficiency and the test accuracy of the silicon wafer input reproducibility are improved.

In a preferred embodiment of the present invention, the immersion area is disposed in the middle of the projection area of the immersion lithography machine.

In a preferred embodiment of the present invention, the measuring position and the projection area are located on the same plane.

Specifically, in this embodiment, the measurement position and the projection area are arranged on the same plane, so that the reproducibility of the test silicon wafer input is consistent with the operation flow of the silicon wafer input in the actual etching process, and only the difference of the horizontal position exists, thereby achieving the test data most similar to the actual operation.

In a preferred embodiment of the present invention, the test silicon wafer at the measurement position overlaps the projection region.

Specifically, in the embodiment, the position relationship between the test silicon wafer and the projection area is further defined, so that the test process is closer to the actual operation, meanwhile, the contact between the liquid immersion area and the test silicon wafer is avoided, and a better test effect is achieved.

In a preferred embodiment of the present invention, the test mark is disposed on a side of the test silicon wafer close to the soaking region when the test silicon wafer is at the measuring position.

Specifically, in this embodiment, the test mark is disposed on the side of the test silicon wafer, so that the position between the liquid immersion area and the test silicon wafer can be more conveniently controlled when the measurement position is set, and it is avoided that the liquid immersion area and the test silicon wafer are not contacted at the same time due to the test mark disposed in the middle of the test silicon wafer and the test mark is detected by the mark measurement device.

In a preferred embodiment of the present invention, in step S4, the mark measuring device includes a measuring lens, and the measuring lens tests the mark area of the test silicon wafer.

Specifically, in this embodiment, the image on the test silicon wafer is acquired by using the measurement lens, and then the position of the test mark is determined.

In a preferred embodiment of the present invention, the marking region is a square region.

In a preferred embodiment of the present invention, the test mark comprises a plurality of mark points.

Specifically, in this embodiment, the plurality of mark points are adopted, so that the mark measuring device obtains more accurate test data by comparing and testing the plurality of mark points.

In a preferred embodiment of the present invention, each of the marking points is disposed in the marking area.

In a preferred embodiment of the present invention, the test data is an offset between the test mark and the standard position;

in step S7, the average value of the test data is calculated to obtain the test result.

In a preferred embodiment of the present invention, as shown in fig. 3, the test silicon wafer 1 and the liquid immersion area 3 are not overlapped and contacted with each other, and since the positions of the mark area 5 and the liquid immersion area 3 measured by the measuring lens are relatively fixed, the separation of the test silicon wafer 1 from the liquid immersion area 3 of the projection area 4 by adjusting the measurement position is realized by arranging the test mark 2 at a side close to the liquid immersion area 3, and compared with the existing test scheme shown in fig. 2, the technical problem that the test silicon wafer 1 needs to be coated with a waterproof coating is solved by the technical scheme of the present invention.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.

Claims (8)

1. A method for measuring the input reproducibility of a silicon wafer is characterized by being applied to a liquid immersion lithography machine and comprising the following steps of:

step S1: providing a test silicon wafer, and arranging a test mark on the test silicon wafer;

step S2: placing the test silicon wafer in a conveying system of the liquid immersion lithography machine;

step S3: the test silicon wafer is conveyed to a measuring position by adopting the conveying system, and the test silicon wafer positioned at the measuring position is not contacted with a liquid immersion area of the liquid immersion lithography machine;

step S4: measuring the position of the test mark by using a mark measuring device to obtain a group of test data;

step S5: moving the test silicon wafer out of the measuring position by adopting the conveying system;

step S6: judging whether the quantity of the test data meets the preset required quantity or not;

if yes, go to step S7; if not, returning to the step S3;

step S7: calculating all the test data to obtain a test result of the silicon chip input reproducibility;

the liquid immersion area is arranged in the middle of a projection area of the liquid immersion lithography machine;

the test mark is arranged on one side, close to the immersion area, of the test silicon wafer when the test silicon wafer is located at the measuring position, so that the situation that the liquid immersion area is not contacted with the test silicon wafer and the mark measuring device probes the test mark due to the fact that the test mark is arranged in the middle of the test silicon wafer is avoided.

2. A method of measuring silicon wafer launch repeatability according to claim 1 wherein said measurement location is in the same plane as said projection area.

3. The method of claim 1, wherein the test wafer at the metrology position overlaps the projection region.

4. The method of claim 1, wherein in step S4, the mark measuring device comprises a measuring lens, and the measuring lens tests the mark area of the test silicon wafer.

5. The method of claim 4, wherein the mark region is a rectangular region.

6. The method of claim 4, wherein the test mark comprises a plurality of mark points.

7. The method of claim 6, wherein each of the mark points is disposed in the mark region.

8. The method of claim 1, wherein the test data is an offset of the test mark from a standard position;

in step S7, calculating an average value of the test data is adopted to obtain the test result.

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