CN101989047B

CN101989047B - Method for detecting pattern topography of maskplate by dual exposure method

Info

Publication number: CN101989047B
Application number: CN2009100576848A
Authority: CN
Inventors: 吴鹏
Original assignee: Shanghai Hua Hong NEC Electronics Co Ltd
Current assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Priority date: 2009-07-30
Filing date: 2009-07-30
Publication date: 2012-08-01
Anticipated expiration: 2029-07-30
Also published as: CN101989047A

Abstract

The invention discloses a method for detecting the pattern topography of a maskplate by a dual exposure method, which comprises the following steps of: 1) symmetrically placing a pattern to be detected on the maskplate by taking the maskplate as a center; 2) exposing a silicon sheet for the first time and stopping on an exposure platform of a lithography machine without developing; 3) taking the maskplate out of the lithography machine and placing back to the lithography machine after 180-degree rotation; 4) exposing the silicon sheet for the second time after the maskplate is aligned; 5) performing the subsequent normal lithography processes; and 6) forming a complete pattern to be detected on the silicon sheet and measuring. The invention further provides a measuring and quantifying means besides observation of the pattern topography by the conventional method.

Description

A kind of method of utilizing the double exposure method to detect mask plate figure pattern

Technical field

The present invention relates to the detection method of figure pattern in a kind of mask plate manufacturing, particularly relate to a kind of method of utilizing the double exposure method to detect mask plate figure pattern.

Background technology

Because the perpendicularity of figure pattern on the mask plate, symmetry can be through photoetching, and etching technics is directly delivered on the silicon chip, and then finally has influence on the performance performance of chip.Straight, symmetrical mask plate figure pattern is the basic guarantee of photoetching process.

Traditional mask plate figure pattern detection method mainly is to judge its verticality, symmetry through the section section; Or through simulation photo-etching machine exposal height emulation mask plate pattern; Or through mask plate 180 degree rotation exposures, whether corresponding anti-phase is defined with the mask plate rotation according to its feature pattern.Preceding two kinds of methods need expend sizable cost, and do not meet the actual production demand; Then a kind of detection means only can be judged through image, can't measure, and also quantized data can't be provided.

Summary of the invention

The technical matters that the present invention will solve provides a kind of method of utilizing the double exposure method to detect mask plate figure pattern, can not only observe the figure pattern in a conventional manner through this method, also can quantize the problems of measurement that mask plate pattern difference is caused.

For solving the problems of the technologies described above, the method for utilizing the double exposure method to detect mask plate figure pattern of the present invention, step comprises:

1) figure to be measured on the mask plate is placed with mask plate center symmetry, with the form of group one by one correspondence be positioned in the scribe line;

2) silicon chip is accomplished for the first time earlier and is stopped on the photo-etching machine exposal platform after the exposure, does not do development;

3) mask plate, litho machine is put back to litho machine after taking out do 180 degree rotations;

4) after mask plate was accomplished and aimed at (accomplishing automatically), silicon chip carried out the exposure second time (utilizing original mask plate alignment mark to accomplish exposure), and in this exposure, silicon chip rests on the exposure stage all the time;

5) carry out subsequently normal photolithography flow process, comprise development, baking;

6) form complete figure to be measured on the silicon chip, measure.

Figure to be measured in the said step 1) is the arbitrary form figure that meets the double exposure needs, can be one or more groups (one or more pairs of).

Center symmetry in the said step 1) is to be center symmetry with mask plate self alignment mark.

Measurement in the said step 6) is to utilize figure to be measured pre-designed on the mask plate to measure with the mode of alignment, and the size of the 3sigma value through calculating the figure X to be measured that forms on the silicon chip, Y direction defines.

Beneficial effect of the present invention:

1) the present invention can be used to detect mask plate figure pattern, especially asymmetrical graphic pattern;

The fixed characteristics of silicon slice platform when 2) utilizing mask plate self registration mark center symmetry and exposure have guaranteed alignment precision the highest when first and second time makes public;

3) after double exposure is accomplished, can form a complete figure to be measured on the silicon chip, can the difference of mask plate figure pattern be quantized through measuring just.

Therefore, the present invention more provides a kind of means that can measure, quantize except observing in a conventional manner the figure pattern.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the present invention is done further detailed explanation:

Fig. 1 is mask plate self alignment mark and exposure figure district synoptic diagram, and wherein, 1 is the mask plate alignment mark, and 2 is the exposure figure district, and 3 is photo-shield strip;

Fig. 2 is that figure to be measured is placed synoptic diagram;

Fig. 3 is after accomplishing double exposure, the pictorial diagram complete to be measured that mark A1 and A2 form.

Embodiment

The present invention realizes that through utilizing the double exposure method concrete steps comprise in order to detect mask plate figure pattern:

1) figure to be measured on the mask plate is placed with mask plate center symmetry; With the group form one by one correspondence be positioned in the scribe line; Wherein, Figure to be measured is the arbitrary form figure that meets the double exposure needs, can be one or more groups, and the center symmetry is to be center symmetry with mask plate self alignment mark;

4) after mask plate was accomplished aligning automatically, silicon chip carried out the exposure second time (utilizing original mask plate alignment mark to accomplish exposure), and in this exposure, silicon chip rests on the exposure stage all the time;

6) form complete figure to be measured on the silicon chip; Measure; This measurement is to utilize figure to be measured pre-designed on the mask plate to measure with the mode of alignment, and the size of the 3sigma value through calculating the figure X to be measured that forms on the silicon chip, Y direction defines.

In the above-mentioned steps, mask plate self alignment mark synoptic diagram is seen Fig. 1 (mark 3), but the mask aligner mask plate alignment mark of different multiplying, model can be variant.The mark 2 among Fig. 1 is seen in the exposure figure district, comprises the aligning that chip data and process monitoring are required, figure to be measured etc.The size in the chip data district among Fig. 1 is as being 21.6*21.6mm (1X).The size of the photo-shield strip among Fig. 1 is as being 1500 μ m (4X).Figure to be measured is placed synoptic diagram such as Fig. 2, and it is placed on the exposure figure district, and every group of figure to be measured is with mask plate center symmetry.

Operate according to above-mentioned steps, after accomplishing double exposure, the perfect measurement figure (on the silicon chip) that mark A1 can form with A2, then the rest may be inferred for mark B1 and B2, finally as shown in Figure 3, and d is a distance.

The present invention utilizes the method for double exposure and mask plate 180 degree rotations with the mutual alignment of the figure of mask plate diverse location; Final one or more groups resolution chart that can supply measure that forms; If the figure pattern on these diverse locations there are differences; Can define the figure pattern quality of diverse location on the mask plate through the size of calculating the 3sigma value of these resolution charts X, Y direction on the silicon chip; And the size of the asymmetry of these resolution chart different directions and difference also can be reflected on the concrete 3sigma value on the mask plate, through just can guarantee the figure pattern of mask plate to the management and control of 3sigma value.

Claims

1. method of utilizing the double exposure method to detect mask plate figure pattern, step comprises:

1) figure to be measured on the mask plate is placed with mask plate center symmetry; The center symmetry is to be center symmetry with mask plate self alignment mark; Said figure to be measured is the arbitrary form figure that meets the double exposure needs, be with the group form one by one correspondence be positioned in the scribe line, wherein, the form of group is one or more groups; Said figure to be measured is placed with mask plate center symmetry and is meant; The composite figure of forming each group of said figure to be measured all comprises two marks; It is on the centrosymmetric position that the not isolabeling of each group is positioned over said mask plate self alignment mark; The not isolabeling of each group through 180 degree rotations after mutually alignment form the composite figure of each group, form said figure to be measured by one or more groups the said composite figure of mutual alignment;

2) silicon chip is accomplished for the first time earlier and is stopped on the photo-etching machine exposal platform after the exposure, does not do development; After accomplishing exposure for the first time, the difference of each group of the figure to be measured on the said mask plate is marked at and forms exposure figure for the first time on the said silicon chip;

4) after mask plate was accomplished and aimed at, silicon chip carried out the exposure second time; After accomplishing exposure for the second time, the not isolabeling of each group of the figure to be measured on the said mask plate forms exposure figure for the second time; Not isolabeling of each group forms said first time, exposure figure and the mutual alignment of the said exposure figure second time formed the composite figure of said each group, formed said figure to be measured by one or more groups the said composite figure of mutual alignment;

5) carry out subsequently normal photolithography flow process;

6) on said silicon chip, form complete figure said to be measured, said figure to be measured is measured.

2. the method for utilizing the double exposure method to detect mask plate figure pattern as claimed in claim 1 is characterized in that: mask plate is to accomplish automatically to aim in the said step 4); In the exposure, silicon chip rests on the exposure stage all the time for the second time.

3. the method for utilizing the double exposure method to detect mask plate figure pattern as claimed in claim 1 is characterized in that: the normal photolithography flow process subsequently in the said step 5) comprises development, baking.

4. the method for utilizing the double exposure method to detect mask plate figure pattern as claimed in claim 1; It is characterized in that: the measurement in the said step 6) is to utilize figure to be measured pre-designed on the mask plate to measure with the mode of alignment, promptly comes said figure to be measured is measured through the said composite figure of measuring each group respectively; The size of the 3sigma value through calculating the figure X to be measured that forms on the silicon chip, Y direction defines.