CN200989993Y

CN200989993Y - Long mask plate for double-exposure

Info

Publication number: CN200989993Y
Application number: CNU2006200494430U
Authority: CN
Inventors: 姚峰英
Original assignee: Shanghai Integrated Circuit Research and Development Center Co Ltd
Current assignee: Shanghai IC R&D Center Co Ltd
Priority date: 2006-12-22
Filing date: 2006-12-22
Publication date: 2007-12-12
Anticipated expiration: 2016-12-22

Abstract

The utility model relates to a double exposure long mask plate. The width of the long mask plate is increased appropriately to a length bigger than normal width so that the double exposed graphs stay within the flat center area to decrease the focus bending value to an acceptable range. The dimension of the mask plate ranges between: the width ranges between two hundred millimeters and three hundred and fifty millimeters and the length ranges between two hundred and fifty millimeters and three hundred and fifty millimeters. The double exposed graph areas on the mask plate form a rectangle, the shorter edge of which stays at the central position in the width direction of the mask plate. The two areas are exposed by scan once which usually takes twice scan and a move of an exposure table, thereby reducing dramatically the double exposure time, easing the difficulty of applying the doubling exposure technology into large-scale production.

Description

A kind of double exposure long mask

Technical field

The utility model belongs to field of IC technique, relates to the photoetching machine technique in the photolithographic exposure of integrated circuit fabrication process, is specifically related to a kind of double exposure long mask.

Background technology

Along with the continuous development of integrated circuit, transistorized minimum feature is constantly dwindled.Constantly dwindling of characteristic line breadth caused increasing substantially of chip integration, but also brought great challenge to optical lithography processes.

For the minimum feature of expansion optical photoetching technique, the technology serviceable life of the existing lithographic equipment of prolongation, it is very attractive adopting double exposure technique at key level.But the shortcoming of double exposure technique is to be doubled the time shutter with two masks respectively to one deck exposure twice, and machine efficiency reduces by half, and therefore can reduce output greatly and increase considerably cost, and this is that production is undesirable; The alignment issues that also has double exposure to cause is also worrying in addition.Exactly because so, double exposure technique does not still become the technology that actual big production is adopted so far, but rests on laboratory stage always.

The insider knows, uses to add the efficient that long mask can improve double exposure, still, owing to add the existence of himself gravity of long mask, the problem of focussing plane bending can occur owing to the sagging focusing surface that causes in the middle part of mask is inconsistent.

The utility model content

The purpose of this utility model is to overcome the deficiencies in the prior art or defective, a kind of double exposure long mask is provided, make center that the graphics field of double exposure is positioned at its Width than flat site, with bending value that reduces focusing curve and the crooked indication range that reaches permission by the width that strengthens former long mask.

To achieve these goals, the utility model has adopted following technical scheme:

A kind of double exposure long mask, its substantive distinguishing features be,

The width of described mask is greater than normal value;

When the length of this mask was 250mm～350mm, its width can be 200mm～350mm;

The graphics field of double exposing on the described mask is positioned at comparatively smooth zone, its center.

Above-mentioned a kind of double exposure long mask, wherein, the zone that figure constituted of double exposure is a rectangle, the minor face of this rectangular region is positioned at the center of described mask Width.

Above-mentioned a kind of double exposure long mask, wherein, when described mask is held, two long limit relative fixed, two minor faces are active state.

Owing to adopted above-mentioned technical scheme, the utility model compared with prior art has following advantage and good effect:

The utility model is by taking to strengthen the method for former long mask width, a kind of double exposure long mask is provided, the long mask that utilizes this to widen, can make the graphics field of double exposure be positioned at the center of mask Width than flat site, thereby the bending value that reduces focusing curve also finally reaches the crooked indication range of permission.

Description of drawings

By following examples and in conjunction with the description of its accompanying drawing, can further understand the purpose of this utility model, specific structural features and advantage.In the accompanying drawing,

Fig. 1 is the plan structure synoptic diagram of common long mask;

The structural representation of the gravity sag problem that Fig. 2 need solve for common long mask;

Fig. 3 is that common long mask is because the structural representation of the focusing curve bending that gravity sag causes;

Before and after increasing, its width of the mask that Fig. 4 relates to for the utility model overlooks comparative effectiveness figure;

Fig. 5 increases the sagging situation of mask of front and back and the effect comparison diagram of focusing curve bending for the mask width.

Among the figure: 1. first mask graph; 2. second mask graph; 3. Jia Chang mask; 4. the spacing between two mask graphs; 5. the minor face of long mask; 6. the long limit of long mask; 7. be desirable mask section; 8. the actual long mask section that adds; 9. gravity direction; 10. photoetching machine lens; 11. the focusing curve of desirable mask; 12. the focusing curve of actual flexion mask; 13. two long limits of the mask before the lengthening width; 14. two long limits of the mask behind the lengthening width; 15. the mask behind the lengthening width is wide; 16. widen the sagging situation of mask behind the mask width; 17. widen the focusing curve of mask after lens focus behind the mask width.

Embodiment

Referring to Fig. 1, the double exposure long mask that the utility model relates to, be to make its paranormal width value by the width that strengthens long mask 3, thereby make the exposure figure zone be positioned at comparatively smooth zone, long mask 3 centers, focus on bending value and make it arrive the scope that is allowed to reduce.

Fig. 1 has represented the plan structure synoptic diagram of common long mask, two

mask graphs

1,2 that are used to double expose are set at the mask 3 of same lengthening, the

mask graph

1,2 of double exposure is positioned at the central authorities that add long mask 3, and its mutual spacing 4 is by the product decision of the enlargement factor of designed scribe line width and used camera lens.Usually the Width of mask is 100mm～200mm like this, and its representative value is 150mm; Length direction 250mm～350mm, its representative value are 275mm.When this mask of clamping, the both sides on its long limit 6 are fixed, the both sides of minor face 5 are active state.

Fig. 2 has illustrated the gravity sag problem of common long mask: if we observe its section along direction 5, desirable mask 7 should be complete level, but because of adding the effect that long mask is subjected to gravity 9, the situation of actual mask version is shown in 8, its two long limit 6 is owing to be subjected to the effect of holding force, the position at place is higher relatively, but residing position, its center is then relatively low.

When Fig. 3 left side was illustrated in desirable level mask 7, the focusing curve along direction 5 after camera lens 10 imagings was 11, is the level of state; Fig. 3 the right be for reality add the focusing curve 12 of long mask 8 after camera lens 10 imagings, with the crooked situation unanimity of mask 3, promptly low between the senior middle school of both sides.

For the amount of bow that solves focusing curve 12 problem bigger than normal, the utility model takes to alleviate by the method for widening mask 3 width the degree of crook of mask 3, and its amount of bow is controlled in the numerical range of defined.

Specific practice is to strengthen the width of long mask 3, as shown in Figure 4, expands as solid line 14 from two long limit dotted lines 13 just often, value 100mm～200mm from normal minor face 5, representative value 150mm, the minor face value 15 that extends to behind the lengthening is 200mm～350mm, representative value 275mm.

Like this, after the width of long mask 3 is broadened, as shown in Figure 5, the sagging situation of long mask promptly from before section 8 become present section 16, if exposure figure is positioned at the center of the Width of long mask 3, then the degree of crook of these long mask 3 figures will reduce greatly; Focusing curve also from before curve 12 become curve 17, the amount of bow of the focusing curve in central figure district reduces within the allowed band.

In sum, be not difficult to find out that double

exposure mask graph

1,2 zones that constituted on the long mask 3 are rectangle, the minor face of this rectangular region is positioned at the center of mask 3 Widths.The spacing 4 of two

mask graphs

1,2 equals the enlargement factor that the scribe line width multiply by camera lens.

The following examples illustrate possible implementation process of the present utility model, its objective is and explain utilization of the present utility model better, and not should be understood to restriction of the present utility model.

Embodiment 1

Produce a kind of enlargement factor and be 4 times long mask:

1. in the photoetching process of 0.13um technology, requirement according to photoetching depth of focus permissible range, the difference of mask figure sagging peak that causes in zone and minimum point is in 0.48um, for guaranteeing this requirement, the width added value of mask is bigger, its width value can be decided to be 285mm, the broadside center that is centered close to of exposure figure;

2. the polylith long mask that with width is 285mm is measured its focus characteristics curve along scanning seam direction after block-by-block clamping on the litho machine;

3. all curves of measuring are done weighted mean, check the deviate of two curves;

4. the deviate until two curves has dropped in the scope that is allowed.

Embodiment 2

Produce a kind of enlargement factor and be 5 times long mask:

1. in the photoetching process of 0.13um technology, requirement according to photoetching depth of focus permissible range, the difference of mask figure sagging peak that causes in zone and minimum point is in 0.75um, for guaranteeing this requirement, the width added value of mask can reduce relatively, its width value can be decided to be 245mm, the broadside center that is centered close to of exposure figure;

2. the polylith long mask that with width is 245mm is measured its focus characteristics curve along scanning seam direction after block-by-block clamping on the litho machine;

4. the deviate until two curves has dropped in the scope that is allowed.

Claims

1, a kind of double exposure long mask is characterized in that,

The width of described mask is greater than normal value;

When the length of this mask was 250mm～350mm, its width can be 200mm～350mm;

2, a kind of double exposure long mask according to claim 1 is characterized in that the zone that figure constituted of double exposure is a rectangle, and the minor face of this rectangular region is positioned at the center of described mask Width.

3, a kind of double exposure long mask according to claim 1 and 2 is characterized in that, when described mask is held, and two long limit relative fixed, two minor faces are active state.