CN101452202A - PSM, exposure focus calibrating method by utilizing PSM and system thereof - Google Patents

Abstract

The invention relates to a PSM and an exposure machine bench focal length calibration method and device through the PSM, which relates to the field of semi-conductor exposure process. The PSM comprises a plurality of transmission areas made of transmission materials, and a plurality of frames made of non-transmission materials, wherein at least two transmission areas have preset optical path difference; and an exposure pattern comprises a plurality of patterns corresponding to the plurality of the frames. The invention controls the adjustment of the focal length of the exposure machine bench according to mutual position relations of the frames and the patterns to be detected. The method and the device have the advantages of improving the production efficiency, and saving time, together with high calibration precision and simple operation.

Description

A kind of PSM and the exposure bench focus calibrating method and the system thereof that utilize PSM

Technical field

The present invention relates to the semiconductor exposure technology field, be specifically related to a kind of phase deviation light shield (PSM, Phase Shift Mask) and the exposure bench focus calibrating method and the device thereof that utilize PSM.

Background technology

The focus process of photoetching process has important effect to the quality of the chip of manufacturing.In the production of integrated circuit, photoetching process comprises exposure process, and silicon chip at first is positioned within the focusing range of exposure bench optical system, and ultraviolet light is by exposure bench optical system and mask plate patterns projection then.Mask plate patterns appears on the silicon chip with bright dark feature, so just to resist exposure.

Different integrated circuit technology processes all has a special focal length precision specification, if the focusing of the exposure process in the photoetching process is undesirable, the skew of exposure back product pattern will be caused, these skews comprise the variation of shape and critical size bar (CD bar, critical dimension bar) live width etc.Thereby in exposure process, require to keep described special focal length accuracy specifications and forbidden the offset problem that brings to avoid focusing.In actual production, need frequently the focal length of exposure bench to be calibrated, deviation does not appear to guarantee it.

The exposure bench calibration program of prior art is the one group of exposure focal length value that sets in advance exposure bench, utilizes described one group of exposure focal length value to expose then, draws one group according to the CD bar live width after the exposure of described one group of exposure focal length value.Then, according to above-mentioned experimental data, be that horizontal ordinate is that ordinate is made a curve with CD bar live width with the exposure bench focal length value.

Such as, prior art has preestablished one group of exposure focal length, and obtains one group according to the CD bar live width after the exposure of exposure focal length value, and is as shown in the table:

Exposure focal length value (um)	CD bar live width (um)
		-0.35	0.1604
-0.30	0.1840
		-0.25	0.1779
-0.20	0.1946
		-0.15	0.1875
-0.10	0.1938
		-0.05	0.2037
-0.00	0.2024
		0.05	0.1977
0.10	0.1997
		0.15	0.1947
0.20	0.1961
		0.25	0.1960
0.30	0.1826
		0.35	0.1820

With reference to Fig. 1, be that horizontal ordinate is an ordinate with CD bar live width with the exposure focal length of predefined exposure bench, make a curve.And work out a level and smooth curve according to described curve, the place, summit of described smooth curve is exactly the pinpointed focus value that prior art is thought.

But prior art is by the manual measurement experimental data, and also is an approximate process by the curve that described experimental data obtains, and therefore has very important error; In addition, extraneous factor also can cause the inaccurate of calibration result, as the quality of the employed wafer error introduced such as flatness or exposure bench itself for example; And, various in whole calibration process step, expend the plenty of time, resulting data processing complex, not directly perceived, trivial operations has reduced production efficiency and has wasted manpower.

Summary of the invention

The purpose of this invention is to provide a kind of PSM and the exposure bench focus calibrating method and the device that utilize PSM, to improve the calibration accuracy of exposure bench focal length.

According to a first aspect of the invention, provide a kind of phase deviation light shield that is used for the focal length calibration of semiconductor exposure board, it is characterized in that, having comprised:

A plurality of transmission regions of making by light transmissive material, wherein at least two transmission regions have predetermined optical path difference;

A plurality of frames of making by non-light transmissive material;

The inner and outer boundary of described each frame is respectively with any two are adjacent or join in described a plurality of transmission regions,

Wherein, wherein at least two frames are placed as, and make when utilizing this light shield to expose gained inconsistent with the offset direction that the exposure bench focal length variations produces with the corresponding exposing patterns of described at least two frames.

According to a second aspect of the invention, provide a kind of exposure bench focus calibrating method that utilizes the phase deviation light shield, it is characterized in that comprising the steps:

A. under predetermined focal distance, utilize exposure bench that one phase deviation light shield is exposed, form an exposing patterns,

Wherein this phase deviation light shield comprises: a plurality of transmission regions of making by light transmissive material, and wherein at least two transmission regions have predetermined optical path difference; A plurality of frames that formed by non-light transmissive material, the inner and outer boundary of described each frame are respectively with any two are adjacent or join in described a plurality of transmission regions,

Wherein, wherein at least two frames are placed as, make when utilizing this light shield to expose, and gained inconsistent with the offset direction that the exposure bench focal length variations produces with the corresponding exposing patterns of described at least two frames,

Wherein, described exposing patterns comprises a plurality of patterns corresponding with described a plurality of frames,

B. detect the mutual alignment relation between described a plurality of pattern.

According to a third aspect of the invention we, provide a kind of exposure bench focal length calibration device that utilizes the phase deviation light shield, it is characterized in that its structure comprises:

Detecting device is used to detect the relative displacement that utilizes the pattern after exposure bench exposes to a phase deviation light shield under predetermined focal distance, sends detection signal,

Wherein this phase deviation light shield comprises: a plurality of transmission regions of making by light transmissive material, and wherein at least two transmission regions have predetermined optical path difference; A plurality of frames that formed by non-light transmissive material, the inner and outer boundary of described each frame are respectively with any two are adjacent or join in described a plurality of transmission regions,

Wherein, wherein at least two frames are placed as, make when utilizing this light shield to expose, and gained inconsistent with the offset direction that the exposure bench focal length variations produces with the corresponding exposing patterns of described at least two frames,

Wherein, described exposing patterns comprises a plurality of patterns corresponding with described a plurality of frames.

The relative position of a plurality of patterns that the present invention forms after exposing by a plurality of frames comes the precision of calibrated focal length, the degree of accuracy height, and error is little; Use the present invention can intuitively calibrate the exposure bench focal length easily, and simple to operate, and exposure bench focal length calibration scheme has compared to existing technology improved production efficiency and has saved the time.

Description of drawings

By reading the following detailed description of doing with reference to accompanying drawing to non-limiting example, other features, objects and advantages of the present invention will become more obvious.

Fig. 1 determines the curve map of exposure bench pinpointed focus for prior art;

Fig. 2 is the structural representation of the phase deviation light shield of embodiments of the invention one;

Fig. 3 is first transmission region of embodiments of the invention one and the diagrammatic cross-section of second transmission region position relation;

Fig. 4 is the exposing patterns synoptic diagram of the normal focusing of exposure bench of embodiments of the invention one;

Fig. 5 moves the exposing patterns synoptic diagram of focusing for the exposure bench negative bias of embodiments of the invention one;

Fig. 6 just is being offset the exposing patterns synoptic diagram of focusing for the exposure bench of embodiments of the invention one;

Fig. 7 is the structural representation of the phase deviation light shield of embodiments of the invention two;

Fig. 8 is first transmission region of embodiments of the invention two and the diagrammatic cross-section of second transmission region position relation;

Fig. 9 is the exposing patterns synoptic diagram of the normal focusing of exposure bench of embodiments of the invention two;

Figure 10 moves the exposing patterns synoptic diagram of focusing for the exposure bench negative bias of embodiments of the invention two;

Figure 11 just is being offset the exposing patterns synoptic diagram of focusing for the exposure bench of embodiments of the invention two;

Figure 12 is the structural representation of the phase deviation light shield of embodiments of the invention three;

Figure 13 is first transmission region of embodiments of the invention three and the diagrammatic cross-section of second transmission region position relation;

Figure 14 is the exposing patterns synoptic diagram of the normal focusing of exposure bench of embodiments of the invention three;

Figure 15 moves the exposing patterns synoptic diagram of focusing for the exposure bench negative bias of embodiments of the invention three;

Figure 16 just is being offset the exposing patterns synoptic diagram of focusing for the exposure bench of embodiments of the invention three;

Figure 17 is the structural representation that utilizes the exposure bench focal length calibration device of phase deviation light shield of the present invention.

Embodiment

Below in conjunction with accompanying drawing the present invention is described in further detail.

The phase deviation light shield is a kind of light shield commonly used in the integrated circuit manufacture process.Described phase deviation light shield is on the figure of traditional light shield, optionally adds transparent at photic zone but can make the reverse transmission region of light beam phase reversal π, exposes with this light shield, and the analytic ability of exposure system is heightened.

According to formula:

$\mathrm{\φ}=\frac{(n-1).d}{\mathrm{\λ}}.2\mathrm{\π}$ Formula (1)

Wherein φ is the phase place that sees through the light of described reverse transmission region, i.e. φ=π; λ is for seeing through the light wavelength of described reverse transmission region; N is the refractive index that sees through the light of described reverse transmission region.Because light beam phase reversal π, i.e. φ=π, the thickness of described reverse transmission region is $d=\frac{\mathrm{\φ\λ}}{2\mathrm{\π}(n-1)}=\frac{0.5\mathrm{\λ}}{(n-1)}.$

Pattern after the phase deviation light shield exposure can be along with the variation of exposure focal length whole moving, particularly, promptly expose focal length when bigger than normal when exposure focal length positively biased (Positive Defocus), the pattern after the exposure of phase deviation light shield moves to reverse transmission region; When exposure focal length negative bias (NegativeDefocus) promptly exposes focal length when less than normal, the pattern after the exposure of phase deviation light shield moves to the direction opposite with reverse transmission region.

According to the pattern after the exposure of above-mentioned phase deviation light shield can be along with the variation of exposure focal length the whole character that moves, a first aspect of the present invention provides a kind of phase deviation light shield, its structure comprises: a plurality of transmission regions of making by light transmissive material, and wherein at least two transmission regions have predetermined optical path difference; A plurality of frames of making by non-light transmissive material.The inner and outer boundary of described each frame is respectively with any two are adjacent or join in described a plurality of transmission regions, wherein at least two frames are placed as, make when utilizing this light shield to expose gained inconsistent with the offset direction that the exposure bench focal length variations produces with the corresponding exposing patterns of described at least two frames.

According to a second aspect of the invention, a kind of exposure bench focus calibrating method that utilizes the phase deviation light shield comprises the steps:

A. under predetermined focal distance, utilize exposure bench that one phase deviation light shield is exposed, form an exposing patterns;

B. detect the mutual alignment relation between described a plurality of pattern;

C. according to the mutual alignment relation of described a plurality of frames and the phase position relation of a plurality of patterns that detected, control the focal length of described exposure bench is regulated.

Repeating step b and c, consistent until the mutual alignment of described a plurality of frames relation with the phase position relation of a plurality of patterns that detected.

Wherein, the structure of described phase deviation light shield comprises: a plurality of transmission regions of making by light transmissive material, and wherein at least two transmission regions have predetermined optical path difference; A plurality of frames of making by non-light transmissive material.The inner and outer boundary of described each frame is respectively with any two are adjacent or join in described a plurality of transmission regions, wherein at least two frames are placed as, make when utilizing this light shield to expose gained inconsistent with the offset direction that the exposure bench focal length variations produces with the corresponding exposing patterns of described at least two frames.

According to a third aspect of the invention we, provide a kind of exposure bench focal length calibration device that utilizes the phase deviation light shield, its structure comprises:

Detecting device is used to detect the relative displacement that utilizes the pattern after exposure bench exposes to a phase deviation light shield under predetermined focal distance, sends detection signal,

Controller according to the detection signal that described detecting device sends, sends control signal the focal length of described exposure bench is regulated,

Consistent until the mutual alignment of described a plurality of frames relation with the phase position relation of a plurality of patterns that detected.

Wherein, the structure of described phase deviation light shield comprises: a plurality of transmission regions of making by light transmissive material, and wherein at least two transmission regions have predetermined optical path difference; A plurality of frames of making by non-light transmissive material.The inner and outer boundary of described each frame is respectively with any two are adjacent or join in described a plurality of transmission regions, wherein at least two frames are placed as, make when utilizing this light shield to expose gained inconsistent with the offset direction that the exposure bench focal length variations produces with the corresponding exposing patterns of described at least two frames.

[embodiment one]

In the present embodiment, described a plurality of transmission region comprises first transmission region and second transmission region; Described a plurality of frame comprises concentric inside casing and housing; Described a plurality of pattern comprises first pattern and second pattern.Wherein, the housing of described phase deviation light shield and inside casing are rectangle frame, and second transmission region is arranged on first transmission region top.And the material that first transmission region and second transmission region adopt is a quartz glass, and the material that inside casing and housing adopt is chromium (chrome).Light wavelength λ=248nm, refractive index n=1.45.In the present embodiment, the light that sees through second transmission region with the phase place of the light (i.e. the light of second transmission region and first transmission region) that sees through air is

, promptly $\mathrm{\φ}=\frac{\mathrm{\π}}{2}$ 。

According to a first aspect of the invention, provide a kind of phase deviation light shield.With reference to Fig. 2, its structure comprises: first transmission region 11 and second transmission region 21, concentric housing and inside casing.

Particularly, with reference to figure 2, described housing comprises first strip pattern 311, second strip pattern 321, the 3rd strip pattern 331, the four strip patterns 341, described inside casing comprises the 5th strip pattern 411, the 6th strip pattern 421, the 7th strip pattern 431, the eight strip patterns 441.

Wherein, first strip pattern 311 is the upper side frame of housing, and the latter half that the first half of first strip pattern 311 is positioned at second transmission region, 21, the first strip patterns 311 is positioned at first transmission region 11.

Second strip pattern 321 is the left frame of housing, and the right half part that the left-half of second strip pattern 321 is positioned at second transmission region, 21, the second strip patterns 321 is positioned at first transmission region 11.

The 3rd strip pattern 331 is the lower frame of housing, and the latter half that the first half of the 3rd strip pattern 331 is positioned at second transmission region, 21, the three strip patterns 331 is positioned at first transmission region 11.

The 4th strip pattern 341 is the left frame of housing, and the right half part that the left-half of the 4th strip pattern 341 is positioned at second transmission region, 21, the four strip patterns 341 is positioned at first transmission region 11.

The 5th strip pattern 411 is the upper side frame of inside casing, and the latter half that the first half of the 5th strip pattern 411 is positioned at first transmission region, 11, the five strip patterns 411 is positioned at second transmission region 21.

The 6th strip pattern 421 is the left frame of inside casing, and the right half part that the left-half of the 6th strip pattern 421 is positioned at first transmission region, 11, the six strip patterns 421 is positioned at second transmission region 21.

The 7th strip pattern 431 is the lower frame of inside casing, and the latter half that the first half of the 7th strip pattern 431 is positioned at first transmission region, 11, the seven strip patterns 431 is positioned at second transmission region 21.

The 8th strip pattern 441 is the left frame of described inside casing, and the right half part that the left-half of the 8th strip pattern 441 is positioned at first transmission region, 11, the eight strip patterns 441 is positioned at second transmission region 21.

Further, with reference to Fig. 3, described in the present embodiment second transmission region 21 is arranged on described first transmission region 11 tops.According to formula (1), the thickness d of described second transmission region 21 should be: $d=\frac{\mathrm{\φ\λ}}{2\mathrm{\π}(n-1)}=\frac{0.5\mathrm{\π\λ}}{2\mathrm{\π}(n-1)}\≈110\mathrm{nm},$ λ=248nm wherein, n=1.56, $\mathrm{\φ}=\frac{\mathrm{\π}}{2}.$

Further, in the present embodiment, described predetermined threshold range is-0.2 micron to 0.2 micron.

According to a second aspect of the invention, provide a kind of exposure bench focus calibrating method that utilizes the phase deviation light shield, this method comprises the steps:

A. under predetermined focal distance, utilize exposure bench that above-mentioned phase deviation light shield is exposed, described phase deviation light shield exposure back pattern comprises first pattern 31 and second pattern 41, described first pattern 31 is the pattern after the housing exposure, and described second pattern 41 is the pattern of inside casing after exposing;

B. detect the relative displacement of described first pattern center B1 and the described second pattern center A1.

C. according to the relative displacement that described step b detected, control the adjusting of the focal length of described exposure bench, until the relative displacement value of described first pattern center B1 and the described second pattern center A1 in-0.2 micron to 0.2 micron threshold range.

Respectively three kinds of situations of calibration exposure bench focal length are described below with reference to Fig. 4, Fig. 5 and Fig. 6.

With reference to Fig. 4, find the first pattern center B1 according to first pattern 31, find the second pattern center A1 according to the position of second pattern 41, described first pattern center B1 and the described second pattern center A1 promptly almost overlap in-0.2 micron to 0.2 micron predetermined threshold range.In this case, do not need calibration.

With reference to Fig. 5, find the first pattern center B1 according to first pattern 31, find the second pattern center A1 according to second pattern 41, the second pattern center A1 is on the upper left side of the first pattern center B1 as shown in the figure.According to the pattern after the phase deviation light shield exposure can be along with the variation of exposure focal length mobile character, as can be known in this case inside casing and housing all towards moving with the reverse transmission region direction that promptly second transmission region 12 is opposite, focal length negative bias (NegativeDefocus) for exposure bench, promptly the focal length of exposure bench should increase the focal length of exposure bench less than predetermined focal distance at this moment.

With reference to Fig. 6, find the first pattern center B1 according to first pattern 31, find the second pattern center A1 according to second pattern 41, the second pattern center A1 is in the lower right of the first pattern center B1 as shown in the figure.According to the pattern after the phase deviation light shield exposure can be along with the variation of exposure focal length mobile character, as can be known in this case inside casing and housing all towards moving with the reverse transmission region direction that promptly second transmission region 21 is identical, focal length positively biased (PositiveDefocus) for exposure bench, promptly the focal length of exposure bench should reduce the focal length of exposure bench greater than predetermined focal distance at this moment.

According to the method described above, relative position according to the first pattern center B1 and the second pattern center A1,1 time or repeatedly regulate the exposure bench focal length, until the relative displacement of the check pattern center B1 and the second pattern center A1 in-0.2 micron to 0.2 micron predetermined threshold range, think that promptly the focal length of exposure bench this moment is best, finished the focal length calibration of exposure bench.

According to a third aspect of the invention we, provide a kind of calibrating installation that utilizes the exposure bench focal length of phase deviation light shield, with reference to Figure 17, its structure comprises:

Detecting device 5 is used to detect the first pattern center B1 that utilizes after exposure bench exposes to the phase deviation light shield of present embodiment and the relative displacement of the second pattern center A1, and sends detection signal under predetermined focal distance.

Controller 6, the detection signal that sends according to described detecting device 5, send control signal and regulate the focal length of described exposure bench 7, until the relative displacement value of described first pattern center B1 and the described second pattern center A1 in-0.2 micron to 0.2 micron predetermined threshold range.

The course of work of described device is: first pattern center B1 after detecting device 5 exposes according to phase deviation light shield in the exposure bench 7 and the relative displacement of the second pattern center A1, and send detection signal.Controller 6 sends control signal and returns to exposure bench 7 according to described detection signal, regulates the focal length of exposure bench 7.

Further, under situation shown in Figure 4, the first pattern center B1 and the described second pattern center A1 promptly almost overlap in-0.2 micron to 0.2 micron predetermined threshold range, and control signal comprises does not need information that exposure bench 7 is calibrated.

Under situation shown in Figure 5, the second pattern center A1 is on the upper left side of the first pattern center B1, the focal length negative bias of exposure bench 7 (Negative Defocus), promptly this moment exposure bench 7 focal length less than predetermined focal distance.Control signal has comprised the information that should increase the focal length of exposure bench 7.

Under situation shown in Figure 6, the second pattern center A1 is in the lower right of the first pattern center B1, the focal length positively biased of exposure bench 7 (Positive Defocus), promptly this moment exposure bench focal length greater than predetermined focal distance.Control signal has comprised the information that should reduce the focal length of exposure bench 7.

Said apparatus is according to the relative position of the first pattern center B1 and the second pattern center A1,1 time or repeatedly regulate the exposure bench focal length, until the relative displacement of the first pattern center B1 and the second pattern center A1 in-0.2 micron to 0.2 micron predetermined threshold range, think that promptly the focal length of exposure bench this moment is best, finished the focal length calibration of exposure bench.

[embodiment two]

In the present embodiment, in the present embodiment, described a plurality of transmission regions comprise first transmission region and second transmission region; Described a plurality of frame comprises concentric inside casing and housing; Described a plurality of pattern comprises first pattern and second pattern.The housing of phase deviation light shield and inside casing are circular frame, and second transmission region is the white space part that caves in first transmission region.The material that first transmission region and second transmission region adopt is a quartz glass, and the material that inside casing and housing adopt is chromium (chrome).Light wavelength λ=248nm, refractive index n=1.45.In the present embodiment, the light that sees through second transmission region with the phase place of the light (i.e. the light of second transmission region and first transmission region) that sees through air is

Promptly $\mathrm{\φ}=1\frac{1}{5}\mathrm{\π}.$

According to a first aspect of the invention, provide a kind of phase deviation light shield.Its structure comprises: first transmission region 12 and second transmission region 22, concentric housing and inside casing.

Particularly, with reference to figure 7, described housing comprises the first arcuation pattern 312, the second arcuation pattern 322, the 3rd arcuation pattern 332, the four arcuation patterns 342, described inside casing comprises the 5th arcuation pattern 412, the 6th arcuation pattern 422, the 7th arcuation pattern 432, the eight arcuation patterns 442.

Wherein, the first arcuation pattern 312 is the upper side frame of housing, and the latter half that the first half of the first arcuation pattern 312 is positioned at second transmission region, 22, the second arcuation patterns 312 is positioned at first transmission region 12.

The second arcuation pattern 322 is the left frame of housing, and the left-half of the second arcuation pattern 322 is positioned at second transmission region 22, and the right half part of second arcuation pattern 322 is positioned at first transmission region 12.

The 3rd arcuation pattern 332 is the lower frame of housing, and the latter half that the first half of the 3rd arcuation pattern 332 is positioned at second transmission region, 22, the three arcuation patterns 332 is positioned at first transmission region 12.

The 4th arcuation pattern 342 is the left frame of housing, and the right half part that the left-half of the 4th arcuation pattern 342 is positioned at second transmission region, 22, the four arcuation patterns 342 is positioned at first transmission region 12.

The 5th arcuation pattern 412 is the upper side frame of inside casing, and the latter half that the first half of the 5th arcuation pattern 412 is positioned at first transmission region, 12, the five arcuation patterns 412 is positioned at second transmission region 22.

The 6th arcuation pattern 422 is the left frame of inside casing, and the right half part that the left-half of the 6th arcuation pattern 422 is positioned at first transmission region, 12, the six arcuation patterns 422 is positioned at second transmission region 22.

The 7th arcuation pattern 432 is the lower frame of inside casing, and the latter half that the first half of the 7th arcuation pattern 432 is positioned at first transmission region, 12, the seven arcuation patterns 432 is positioned at second transmission region 22.

The 8th arcuation pattern 442 is the left frame of described inside casing, and the right half part that the left-half of the 8th arcuation pattern 441 is positioned at first transmission region, 12, the eight arcuation patterns 442 is positioned at second transmission region 22.

Further, with reference to Fig. 8, second transmission region 22 is the white space part of depression in first transmission region 12 in the present embodiment.According to formula (1), the thickness d of described second transmission region 22 should be: $d=\frac{\mathrm{\φ\λ}}{2\mathrm{\π}(n-1)}=\frac{1.2\mathrm{\π\λ}}{2\mathrm{\π}(n-1)}\≈265\mathrm{nm}.$ Wherein, λ is a light wavelength, and n is a refractive index.In the present embodiment, λ=248nm, n=1.56, $\mathrm{\φ}=1\frac{1}{5}\mathrm{\π}.$

Further, in the present embodiment, described predetermined threshold range is-2 microns to 5 microns.

According to a second aspect of the invention, provide a kind of exposure bench focus calibrating method that utilizes the phase deviation light shield, this method comprises the steps:

A. under predetermined focal distance, utilize exposure bench that above-mentioned phase deviation light shield is exposed, described phase deviation light shield exposure back pattern comprises first pattern 32 and second pattern 42, described first pattern 32 is the pattern after the housing exposure, and described second pattern 42 is the pattern of inside casing after exposing;

B. detect the relative displacement of described first pattern center B2 and the described second pattern center A2.

C. according to the relative displacement that described step b detected, control the adjusting of the focal length of described exposure bench, until the relative displacement value of described first pattern center B2 and the described second pattern center A2 in-2 microns to 5 microns predetermined threshold range.

Respectively three kinds of situations of calibration exposure bench focal length are described below with reference to Fig. 9, Figure 10 and Figure 11.

With reference to Fig. 9, find the first pattern center B2 according to first pattern 32, find the second pattern center A2 according to the position of second pattern 42, described first pattern center B2 and the described second pattern center A2 promptly almost overlap in-2 microns to 5 microns predetermined threshold range.In this case, do not need calibration.

With reference to Figure 10, find the first pattern center B2 according to first pattern 32, find the second pattern center A2 according to second pattern 42, the second pattern center A2 is on the upper left side of the first pattern center B2 as shown in the figure.According to the pattern after the phase deviation light shield exposure can be along with the variation of exposure focal length mobile character, as can be known in this case inside casing and housing all towards moving with the reverse transmission region direction that promptly second transmission region 22 is opposite, focal length negative bias (NegativeDefocus) for exposure bench, promptly the focal length of exposure bench should increase the focal length of exposure bench less than predetermined focal distance at this moment.

With reference to Figure 11, find the first pattern center B2 according to first pattern 32, find the second pattern center A2 according to second pattern 42, the second pattern center A2 is in the lower right of the first pattern center B2 as shown in the figure.According to the pattern after the phase deviation light shield exposure can be along with the variation of exposure focal length mobile character, as can be known in this case inside casing and housing all towards moving with the reverse transmission region direction that promptly second transmission region 22 is identical, focal length positively biased (PositiveDefocus) for exposure bench, promptly the focal length of exposure bench should reduce the focal length of exposure bench greater than predetermined focal distance at this moment.

According to the method described above, relative position according to the first pattern center B1 and the second pattern center A1,1 time or repeatedly regulate the exposure bench focal length, until the relative displacement of the check pattern center B1 and the second pattern center A1 in-2 microns to 5 microns predetermined threshold range, think that promptly the focal length of exposure bench this moment is best, finished the focal length calibration of exposure bench.

According to a third aspect of the invention we, provide a kind of calibrating installation that utilizes the exposure bench focal length of phase deviation light shield, with reference to Figure 17, its structure comprises:

Detecting device 5 is used to detect the first pattern center B2 that utilizes after exposure bench exposes to the phase deviation light shield of present embodiment and the relative displacement of the second pattern center A2, and sends detection signal under predetermined focal distance.

Controller 6, the detection signal according to described detecting device 5 sends sends the focal length that control signal is regulated described exposure bench 7, until the relative displacement value of described first pattern center and described second pattern center in-2 microns to 5 microns predetermined threshold range.

The course of work of described device is: first pattern center B2 after detecting device 5 exposes according to phase deviation light shield in the exposure bench 7 and the relative displacement of the second pattern center A2, and send detection signal.Controller 6 sends control signal and returns to exposure bench 7 according to described detection signal, regulates the focal length of exposure bench 7.

Further, under situation shown in Figure 9, the first pattern center B2 and the described second pattern center A2 promptly almost overlap in threshold range, and control signal comprises does not need information that exposure bench 7 is calibrated.

Under situation shown in Figure 10, the second pattern center A2 is on the upper left side of the first pattern center B2, the focal length negative bias of exposure bench 7 (Negative Defocus), promptly this moment exposure bench 7 focal length less than predetermined focal distance.Control signal has comprised the information that should increase the focal length of exposure bench 7.

Under situation shown in Figure 11, the second pattern center A2 is in the lower right of the first pattern center B2, the focal length positively biased of exposure bench 7 (Positive Defocus), promptly this moment exposure bench focal length greater than predetermined focal distance.Control signal has comprised the information that should reduce the focal length of exposure bench 7.

Said apparatus is according to the relative position of the first pattern center B2 and the second pattern center A2,1 time or repeatedly regulate the exposure bench focal length, until the relative displacement of the check pattern center B2 and the second pattern center A2 in-2 microns to 5 microns predetermined threshold range, think that promptly the focal length of exposure bench this moment is best, finished the focal length calibration of exposure bench.

[embodiment three]

In the present embodiment, in the present embodiment, described a plurality of transmission regions comprise first transmission region and second transmission region; Described a plurality of frame comprises concentric inside casing and housing; Described a plurality of pattern comprises first pattern and second pattern.The housing of phase deviation light shield and inside casing are special-shaped frame, and second transmission region is the white space part that caves in first transmission region.The material that first transmission region and second transmission region adopt is a quartz glass, and the material that inside casing and housing adopt is chromium (chrome).Light wavelength λ=248nm, refractive index n=1.45.In the present embodiment, the light that sees through second transmission region with the phase place of the light (i.e. the light of second transmission region and first transmission region) that sees through air is

Promptly $\mathrm{\φ}=1\frac{1}{3}\mathrm{\π}.$

According to a first aspect of the invention, provide a kind of phase deviation light shield.Its structure comprises: first transmission region 13 and second transmission region 23, concentric housing and inside casing.

Particularly, with reference to Figure 12, described housing comprises first strip pattern, 313, the second strip patterns 323, the first arcuation pattern 333, and described inside casing comprises the 3rd strip pattern 413, the four strip patterns 423, the second arcuation pattern 433.

Wherein, half of first strip pattern 313 is positioned at second transmission region 23, and second half is positioned at first transmission region 13.

Half of second strip pattern 323 is positioned at second transmission region 23, and second half is positioned at first transmission region 13.

The left-half that the right half part of the first arcuation pattern 333 is positioned at second transmission region, 23, the first arcuation patterns 333 is positioned at first transmission region 13.

Half of the 3rd strip pattern 413 is positioned at first transmission region 13, and second half is positioned at second transmission region 23.

Half of the 4th strip pattern 423 is positioned at first transmission region 13, and second half is positioned at second transmission region 23.

The second arcuation pattern 433 is the left frame of inside casing, and the left-half that the right half part of the second arcuation pattern 433 is positioned at first transmission region, 13, the second arcuation patterns 433 is positioned at second transmission region 23.

Further, with reference to Figure 13, second transmission region 23 is the white space part of depression in first transmission region 13 in the present embodiment.According to formula (1), the thickness d of described second transmission region 23 should be: $d=\frac{\mathrm{\φ\λ}}{2\mathrm{\π}(n-1)}=\frac{1.2\mathrm{\π\λ}}{2\mathrm{\π}(n-1)}\≈295\mathrm{nm}.$ Wherein, λ is a light wavelength, and n is a refractive index.In the present embodiment, λ=248nm, n=1.56, $\mathrm{\φ}=1\frac{1}{3}\mathrm{\π}.$

Further, in the present embodiment, described predetermined threshold range is 0 micron to 2 microns.

According to a second aspect of the invention, provide a kind of exposure bench focus calibrating method that utilizes the phase deviation light shield, this method comprises the steps:

A. under predetermined focal distance, utilize exposure bench that above-mentioned phase deviation light shield is exposed, described phase deviation light shield exposure back pattern comprises first pattern 33 and second pattern 43, described first pattern 33 is the pattern after the housing exposure, and described second pattern 43 is the pattern of inside casing after exposing;

B. detect the relative displacement of described first pattern center B3 and the described second pattern center A3.

C. according to the relative displacement that described step b detected, control the adjusting of the focal length of described exposure bench, until the relative displacement value of described first pattern center B3 and the described second pattern center A3 in 0 micron to 2 microns threshold range.

Respectively three kinds of situations of calibration exposure bench focal length are described below with reference to Figure 14, Figure 15 and Figure 16.

With reference to Figure 14, find the first pattern center B3 according to first pattern 33, find the second pattern center A3 according to the position of second pattern 43, described first pattern center B3 and the described second pattern center A3 promptly almost overlap in 0 micron to 2 microns predetermined threshold range.In this case, do not need calibration.

Because in the present embodiment, inside casing and housing are special-shaped pattern, according to the most left point and the mid point (center of X-direction) of the rightest point and the mid point (center of Y direction) of the first and second pattern highs and lows of exposure back first and second patterns, determine the center of described first and second patterns.

With reference to Figure 15, the center B3X that finds directions X according to the most left point and the rightest point of first pattern 33 finds the center B3Y of Y direction according to the highs and lows of first pattern 33, and the intersection point of B3X and B3Y is the center B3 of first pattern 33.Equally, the center A3X that finds directions X according to the most left point and the rightest point of second pattern 43 finds the center A3Y of Y direction according to the highs and lows of second pattern 43, and the intersection point of A3X and A3Y is the center A3 of first pattern 43.A3 is on the right of B3.According to the pattern after the phase deviation light shield exposure can be along with the variation of exposure focal length mobile character, as can be known in this case inside casing and housing all towards moving with the reverse transmission region direction that promptly second transmission region 22 is opposite, focal length negative bias (Negative Defocus) for exposure bench, promptly the focal length of exposure bench should increase the focal length of exposure bench less than predetermined focal distance at this moment.

With reference to Figure 16, the center B3X that finds directions X according to the most left point and the rightest point of first pattern 33 finds the center B3Y of Y direction according to the highs and lows of first pattern 33, and the intersection point of B3X and B3Y is the center B3 of first pattern 33.Equally, the center A3X that finds directions X according to the most left point and the rightest point of second pattern 43 finds the center A3Y of Y direction according to the highs and lows of second pattern 43, and the intersection point of A3X and A3Y is the center A3 of first pattern 43.A3 is on the left side of B3.According to the pattern after the phase deviation light shield exposure can be along with the variation of exposure focal length mobile character, as can be known in this case inside casing and housing all towards moving with the reverse transmission region direction that promptly second transmission region 22 is identical, focal length positively biased (Positive Defocus) for exposure bench, promptly the focal length of exposure bench should reduce the focal length of exposure bench greater than predetermined focal distance at this moment.

According to the method described above, relative position according to the first pattern center B3 and the second pattern center A3,1 time or repeatedly regulate the exposure bench focal length, until the relative displacement of the check pattern center B3 and the second pattern center A3 in 0 micron to 2 microns threshold range, think that promptly the focal length of exposure bench this moment is best, finished the focal length calibration of exposure bench.

According to a third aspect of the invention we, provide a kind of calibrating installation that utilizes the exposure bench focal length of phase deviation light shield, with reference to Figure 17, its structure comprises:

Detecting device 5 is used to detect the first pattern center B3 that utilizes after exposure bench exposes to the phase deviation light shield of present embodiment and the relative displacement of the second pattern center A3, and sends detection signal under predetermined focal distance.

Controller 6, the detection signal according to described detecting device 5 sends sends the focal length that control signal is regulated described exposure bench 7, until the relative displacement value of described first pattern center and described second pattern center in 0 micron to 2 microns threshold range.

The course of work of described device is: first pattern center B3 after detecting device 5 exposes according to phase deviation light shield in the exposure bench 7 and the relative displacement of the second pattern center A3, and send detection signal.Controller 6 sends control signal and returns to exposure bench 7 according to described detection signal, regulates the focal length of exposure bench 7.

Further, under situation shown in Figure 14, the first pattern center B3 and the described second pattern center A3 promptly almost overlap in threshold range, and control signal comprises does not need information that exposure bench 7 is calibrated.

Under situation shown in Figure 15, the second pattern center A3 is on the right of the first pattern center B3, the focal length negative bias of exposure bench 7 (Negative Defocus), promptly this moment exposure bench 7 focal length less than predetermined focal distance.Control signal has comprised the information that should increase the focal length of exposure bench 7.

Under situation shown in Figure 16, the second pattern center A3 is on the left side of the first pattern center B3, the focal length positively biased of exposure bench 7 (Positive Defocus), promptly this moment exposure bench focal length greater than predetermined focal distance.Control signal has comprised the information that should reduce the focal length of exposure bench 7.

Said apparatus is according to the relative position of the first pattern center B3 and the second pattern center A3,3 times or repeatedly regulate the exposure bench focal length, until the relative displacement of the check pattern center B3 and the second pattern center A1 in 0 micron to 2 microns threshold range, think that promptly the focal length of exposure bench this moment is best, finished the focal length calibration of exposure bench.

Those skilled in the art should know, and a plurality of frames of the present invention can be arbitrary graphics, and can pass through the point of crossing of the mid point of described a plurality of frames exposure X-directions of measurement and Y direction respectively, to confirm the center of described a plurality of frame exposing patterns.As for other arbitrary graphics and arbitrary graphic combination, those skilled in the art can use in the present invention without creative work.

More than specific embodiments of the invention are described.It will be appreciated that the present invention is not limited to above-mentioned specific implementations, those skilled in the art can make various distortion or modification within the scope of the appended claims.

Claims (21)

1. a phase deviation light shield that is used for the focal length calibration of semiconductor exposure board is characterized in that, comprising:

A plurality of transmission regions of making by light transmissive material, wherein at least two transmission regions have predetermined optical path difference;

A plurality of frames of making by non-light transmissive material,

The inner and outer boundary of described each frame is respectively with any two are adjacent or join in described a plurality of transmission regions,

Wherein, wherein at least two frames are placed as, and make when utilizing this light shield to expose gained inconsistent with the offset direction that the exposure bench focal length variations produces with the corresponding exposing patterns of described at least two frames.

2. phase deviation light shield as claimed in claim 1 is characterized in that the shape of described each frame comprises circle, triangle or polygon.

3. phase deviation light shield according to claim 1 and 2 is characterized in that,

Described a plurality of transmission region comprises first transmission region and second transmission region;

Described a plurality of frame comprises concentric inside casing and housing;

The inner and outer boundary of described inside casing and housing faces mutually with described first transmission region and second transmission region respectively or joins,

Wherein, described inside casing and housing are placed as, and make when utilizing this light shield to expose gained inconsistent with the skew side that the exposure bench focal length variations produces with described inside casing and the corresponding exposing patterns of housing.

4. phase deviation light shield as claimed in claim 3 is characterized in that: the thickness of described second transmission region is $d=\frac{\mathrm{\φ\λ}}{2\mathrm{\π}(n-1)},$ Wherein φ is the phase place that sees through the light of described second transmission region, and λ is for seeing through the light wavelength of described second transmission region, and n is the refractive index through the light of described second transmission region.

5. phase deviation light shield as claimed in claim 4, the span of phase that it is characterized in that seeing through the light of described second transmission region is: 0＜φ＜2 π, and φ ≠ π.

6. an exposure bench focus calibrating method that utilizes the phase deviation light shield is characterized in that comprising the steps:

A. under predetermined focal distance, utilize exposure bench that one phase deviation light shield is exposed, form an exposing patterns,

Wherein this phase deviation light shield comprises: a plurality of transmission regions of making by light transmissive material, and wherein at least two transmission regions have predetermined optical path difference; A plurality of frames that formed by non-light transmissive material, the inner and outer boundary of described each frame are respectively with any two are adjacent or join in described a plurality of transmission regions,

Wherein, wherein at least two frames are placed as, make when utilizing this light shield to expose, and gained inconsistent with the offset direction that the exposure bench focal length variations produces with the corresponding exposing patterns of described at least two frames,

Wherein, described exposing patterns comprises a plurality of patterns corresponding with described a plurality of frames,

B. detect the mutual alignment relation between described a plurality of pattern.

7. method according to claim 6 is characterized in that, also comprises:

C. according to the mutual alignment relation of described a plurality of frames and the phase position relation of a plurality of patterns that detected, control the focal length of described exposure bench regulated,

Repeating step b and c, consistent until the mutual alignment of described a plurality of frames relation with the phase position relation of a plurality of patterns that detected.

8. according to claim 6 or 7 described methods, it is characterized in that the shape of described each frame comprises circle, triangle or polygon.

9. method according to claim 8 is characterized in that,

Described a plurality of transmission region comprises first transmission region and second transmission region; Described a plurality of frame comprises concentric inside casing and housing; Described a plurality of pattern comprises first pattern and second pattern,

Wherein, described step b comprises: detect the relative displacement of described first pattern center and second pattern center.

10. method as claimed in claim 9 is characterized in that, described step c also comprises:

-according to the relative displacement that is detected, control the focal length of described exposure bench is regulated, until described relative displacement value less than a predetermined threshold.

11. method as claimed in claim 10 is characterized in that, described step c comprises:

-when the upper left side of second pattern center in first pattern center, the focal length of exposure bench is less than predetermined focal distance, and control increases the focal length of exposure bench;

-when the lower right of second pattern center in first pattern center, the focal length of exposure bench is greater than predetermined focal distance, and control reduces the focal length of exposure bench;

Until the relative displacement value of described first pattern center and described second pattern center less than predetermined threshold.

12. method as claimed in claim 10 is characterized in that, described step c comprises:

-when the left of second pattern center in first pattern center, the focal length of exposure bench is less than predetermined focal distance, and control increases the focal length of exposure bench;

-when second pattern center during on first pattern center right-hand, the focal length of exposure bench is greater than predetermined focal distance, and control reduces the focal length of exposure bench;

Until the relative displacement value of described first pattern center and described second pattern center less than predetermined threshold.

13. as each described method in the claim 10 to 12, it is characterized in that: described predetermined threshold is 0 micron to 10 microns.

14. an exposure bench focal length calibration device that utilizes the phase deviation light shield is characterized in that its structure comprises:

Detecting device is used to detect the relative displacement that utilizes the pattern after exposure bench exposes to a phase deviation light shield under predetermined focal distance, sends detection signal,

Wherein this phase deviation light shield comprises: a plurality of transmission regions of making by light transmissive material, and wherein at least two transmission regions have predetermined optical path difference; A plurality of frames that formed by non-light transmissive material, the inner and outer boundary of described each frame are respectively with any two are adjacent or join in described a plurality of transmission regions,

Wherein, wherein at least two frames are placed as, make when utilizing this light shield to expose, and gained inconsistent with the offset direction that the exposure bench focal length variations produces with the corresponding exposing patterns of described at least two frames,

Wherein, described exposing patterns comprises a plurality of patterns corresponding with described a plurality of frames.

15. device as claimed in claim 14 is characterized in that, its structure also comprises:

Controller according to the detection signal that described detecting device sends, sends control signal the focal length of described exposure bench is regulated,

Consistent until the mutual alignment of described a plurality of frames relation with the phase position relation of a plurality of patterns that detected.

16., it is characterized in that the shape of described each frame comprises circle, triangle or polygon as claim 14 or 15 described devices.

17. device as claimed in claim 16 is characterized in that,

Described a plurality of transmission region comprises first transmission region and second transmission region; Described a plurality of frame comprises concentric inside casing and housing; Described a plurality of pattern comprises first pattern and second pattern,

Wherein, described detecting device is used to detect the relative displacement of first pattern center and second pattern center, sends detection signal.

18. device as claimed in claim 17 is characterized in that, described controller also is used for:

-the detection signal that sends according to described detecting device, control is regulated the focal length of affiliated exposure bench, until described relative displacement value less than a predetermined threshold.

19. device as claimed in claim 18 is characterized in that, described controller is used for:

-when detecting device detected the upper left side of second pattern center in first pattern center, the focal length of exposure bench sent detection signal and gives described controller less than predetermined focal distance, and described controller sends the focal length that control signal control increases exposure bench;

-when detecting device detected the lower right of second pattern center in first pattern center, the focal length of exposure bench sent detection signal and gives described controller greater than predetermined focal distance, and described controller sends the focal length that control signal control reduces exposure bench;

Until the relative displacement value of described first pattern center and described second pattern center less than predetermined threshold.

20. device as claimed in claim 18 is characterized in that, described controller is used for:

-when detecting device detected the left of second pattern center in first pattern center, the focal length of exposure bench sent detection signal and gives described controller less than predetermined focal distance, and described controller sends the focal length that control signal control increases exposure bench;

-when detecting device detected second pattern center on first pattern center right-hand, the focal length of exposure bench sent detection signal and gives described controller greater than predetermined focal distance, and described controller sends the focal length that control signal control reduces exposure bench;

Until the relative displacement value of described first pattern center and described second pattern center less than predetermined threshold.

21. as each described device in the claim 18 to 20, it is characterized in that: described predetermined threshold is 0 micron to 10 microns.

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