CN101158808A - Light shield capable of improving aerial image alignment checking precision degree and photolithography method - Google Patents
Light shield capable of improving aerial image alignment checking precision degree and photolithography method Download PDFInfo
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- CN101158808A CN101158808A CNA2007101705419A CN200710170541A CN101158808A CN 101158808 A CN101158808 A CN 101158808A CN A2007101705419 A CNA2007101705419 A CN A2007101705419A CN 200710170541 A CN200710170541 A CN 200710170541A CN 101158808 A CN101158808 A CN 101158808A
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- aerial image
- image alignment
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- light shield
- precision degree
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- 238000000034 method Methods 0.000 title claims abstract description 49
- 238000000206 photolithography Methods 0.000 title 1
- 229920002120 photoresistant polymer Polymers 0.000 claims abstract description 50
- 239000011248 coating agent Substances 0.000 claims abstract description 3
- 238000000576 coating method Methods 0.000 claims abstract description 3
- 239000003550 marker Substances 0.000 claims description 44
- 238000001259 photo etching Methods 0.000 claims description 37
- 238000005516 engineering process Methods 0.000 claims description 28
- 229910052710 silicon Inorganic materials 0.000 claims description 10
- 239000010703 silicon Substances 0.000 claims description 10
- 239000000758 substrate Substances 0.000 claims description 10
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 7
- 239000002904 solvent Substances 0.000 claims description 4
- 150000001875 compounds Chemical class 0.000 claims description 3
- 239000011347 resin Substances 0.000 claims description 3
- 229920005989 resin Polymers 0.000 claims description 3
- 150000003376 silicon Chemical class 0.000 claims description 3
- 238000003384 imaging method Methods 0.000 abstract description 11
- 238000001459 lithography Methods 0.000 abstract description 3
- 238000012360 testing method Methods 0.000 abstract 2
- 238000007687 exposure technique Methods 0.000 abstract 1
- 239000010410 layer Substances 0.000 abstract 1
- 239000002356 single layer Substances 0.000 abstract 1
- 238000005530 etching Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
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- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
Abstract
The present invention provides a light cover and a lithography method used for the improvement of space imaging overlay test accuracy. Phenomenon of a wider and uneven slope of edge of photoresist which supports a space imaging overlay marked graphics caused by low graphic density of the space imaging overlay marked graphics and low temperature of pre-baking technique exists in the light cover of the prior art, and the phenomenon can not be thoroughly improved by single-layer auxiliary strips arranged on the circumference of the space imaging overlay marked graphics. A plurality of layers of the auxiliary stripes for increasing the graphics density are respectively positioned on the circumference of the space imaging overlay marked graphics arranged inside the light cover of the present invention. The lithography method of the present invention has the coating of the photoresist firstly, then pre-baking technique with a temperature range from 115 DEG C to 125 DEG C, exposure technique by using the light cover, and final developing and post-baking technique are sequentially carried out. The present invention can greatly improve the phenomenon of the wider and uneven slope of edge of photoresist which supports the space imaging overlay marked graphics, and greatly improves the testing accuracy of the space imaging overlay.
Description
Technical field
The present invention relates to photoetching process, relate in particular to a kind of light shield and photoetching method that improves aerial image alignment checking precision degree.
Background technology
In field of semiconductor manufacture, need through supporting photoetching and the etching procedure of multiple tracks, could be to silicon substrate with the figure transfer of semiconductor devices.For guaranteeing the performance of semiconductor devices, need guarantee the alignment precision between the above-mentioned photo-mask process.A plurality of aerial image alignment marker graphics now are set on the employed light shield of per pass photo-mask process usually, judge alignment condition between the twice photo-mask process in the deviation between formed aerial image alignment mark center on the silicon substrate by measuring adjacent twice photoetching and etching procedure.But, because the aerial image alignment marker graphic is arranged on the less Cutting Road of pattern density, so when photoetching, wide and the uneven phenomenon in slope all around in slope at the photoresist edge of this aerial image alignment marker graphic will appear carrying, so will cause the follow-up resulting aerial image alignment mark of etching technics that is carried out down that covers at this photoresist to occur asymmetry occurring, so than large deviation and this aerial image alignment mark with expection aerial image alignment mark size.The precision of aerial image alignment (Overlay) check will be subjected to very big influence.
In addition, above-mentioned figure transfer on the light shield is comprised following technological process to the photoetching process on the photoresist that is coated on the silicon substrate: (1), be coated with photoresist (when minimum feature size was sub-micron or inferior sub-micron grade, employed photoresist was generally positive photoresist) on this silicon substrate; (2), carry out before baking technology, the temperature range of drying by the fire technology before this is 90 degrees centigrade; (3), carry out exposure technology with the figure transfer on the light shield to this photoresist; (4), carry out developing process; (5), carrying out temperature range is 85 to 95 degrees centigrade back baking technology.Preceding baking technological temperature in the above-mentioned steps (2) only is 90 degrees centigrade, also containing a large amount of solvents in the photoresist after the baking technology before finishing causes photoresist firm inadequately, so under the impact of the nitrogen that exposure technology produced of subsequent step (3), can cause the exposure area to expand, thereby aggravate the wide and uneven phenomenon of photoresist margin slope, so will further influence the precision of aerial image alignment checking.
The variety of problems that is produced when overcoming above-mentioned aerial image alignment marker graphic photoetching in the prior art in the following manner: mode one changes the aerial image alignment marker graphic on the light shield into the aerial image alignment marker graphic of negative shape; Mode two, this aerial image alignment marker graphic be peripherally installed with the auxiliary striped of the equally spaced strip of one deck and this aerial image alignment marker graphic periphery, the width of the auxiliary striped of this strip can be 2 microns or 6 microns.Can reduce to carry the photoresist wide and uneven degree in slope all around of this aerial image alignment marker graphic by above-mentioned dual mode, but can not thoroughly improve because the wide and uneven phenomenon of the too small photoresist margin slope that causes of pattern density, moreover to cross its feasibility of die lower because of technology difficulty for mode one.The above analysis, preceding baking technology two aspects when auxiliary striped that can be on improving light shield and photoetching are sought the photoetching process of the variety of problems that solves the above-mentioned precision that influences aerial image alignment checking.
Therefore, how a kind of precision that improves the wide and uneven phenomenon of margin slope of the light shield of aerial image alignment checking precision degree and photoetching method carries this aerial image alignment marker graphic with improvement photoresist and improve aerial image alignment checking is provided, has become the technical matters that industry needs to be resolved hurrily.
Summary of the invention
The object of the present invention is to provide a kind of light shield and photoetching method that improves aerial image alignment checking precision degree, wide and the uneven phenomenon of margin slope of the photoresist of this aerial image alignment marker graphic of carrying can be improved by described light shield and photoetching method, and the precision of aerial image alignment checking can be improved.
The object of the present invention is achieved like this: a kind of light shield that improves aerial image alignment checking precision degree, have a plurality of aerial image alignment marker graphics on this light shield, be provided with the auxiliary striped that multilayer is used to increase its pattern density around this aerial image alignment marker graphic.
In the light shield of above-mentioned improved aerial image alignment checking precision degree, this aerial image alignment marker graphic is a square.
In the light shield of above-mentioned improved aerial image alignment checking precision degree, the center of the auxiliary striped of this each layer overlaps with the center of this aerial image alignment marker graphic.
The present invention also provides a kind of photoetching method that improves the light shield of aerial image alignment checking precision degree as claimed in claim 1 that uses, be used for the figure transfer on this light shield to the photoresist that is coated on the silicon substrate, this method may further comprise the steps: a, coating photoresist step on this silicon substrate; B, carry out before the baking processing step, temperature range of baking technology is 115 to 125 degrees centigrade before this; C, use this light shield to carry out exposure technology so that the aerial image alignment marker graphic on it is transferred to step on this photoresist; D, carry out the developing process step; E, carry out back baking processing step.
In the photoetching method of above-mentioned improved aerial image alignment checking precision degree, behind completing steps e, the thickness of this photoresist is 4 to 5 microns.
In the photoetching method of above-mentioned improved aerial image alignment checking precision degree, in step a, this photoresist is a positive photoresist.
In the photoetching method of above-mentioned improved aerial image alignment checking precision degree, this positive photoresist comprises solvent, resin and Photoactive compounds.
In the photoetching method of above-mentioned improved aerial image alignment checking precision degree, in step b, temperature of baking technology is 120 degrees centigrade before this.
In the photoetching method of above-mentioned improved aerial image alignment checking precision degree, in step e, the temperature range of this back baking technology is 85 to 95 degrees centigrade.
With the auxiliary striped of individual layer only be set around the space imaging overlay mark figure in the prior art cause that its pattern density is low to be compared, the light shield that improves aerial image alignment checking precision degree of the present invention can enlarge markedly its pattern density by the auxiliary striped of multilayer is set around the aerial image alignment marker graphic.
With low excessively wide and inhomogeneous the comparing of photoresist margin slope that causes this aerial image alignment marker graphic of carrying of the temperature that auxiliary striped of individual layer and preceding baking technology only are set around the space imaging overlay mark figure in the prior art, the light shield of aerial image alignment checking precision degree that improves of the present invention is by being provided with the auxiliary striped that multilayer is used to increase its pattern density around the aerial image alignment marker graphic, photoetching method of the present invention use this light shield to carry out photoetching and will be somebody's turn to do before the temperature of baking technology to bring up to by 90 degrees centigrade be 115 to 125 degrees centigrade, so can reduce the slope of the photoresist of this aerial image alignment marker graphic of carrying greatly, and improve its homogeneity greatly, and then can improve greatly and use this aerial image alignment mark to carry out the precision of aerial image alignment checking.
Description of drawings
The photoetching method that improves aerial image alignment checking precision degree of the present invention is provided by following embodiment and accompanying drawing.
Fig. 1 is the synoptic diagram that improves the light shield of aerial image alignment checking precision degree of the present invention;
Fig. 2 is the aerial image alignment marker graphic among Fig. 1 and the enlarged diagram of auxiliary striped on every side thereof;
Fig. 3 is the process flow diagram that improves the photoetching method of aerial image alignment checking precision degree of the present invention.
Embodiment
Below will be described in further detail light shield and the photoetching method that improves aerial image alignment checking precision degree of the present invention.
Referring to Fig. 1 and Fig. 2, have a plurality of aerial image alignment marker graphics 10 on the light shield that improves aerial image alignment checking precision degree of the present invention, be simplicity of illustration and explanation, and other figure on the not shown light shield, described each aerial image alignment marker graphic 10 outside are symmetrically arranged with the auxiliary striped 11 that multilayer is used to increase its pattern density, and the center of the auxiliary striped 11 of this each layer overlaps with the center of this aerial image alignment marker graphic 10.
Continuation is referring to Fig. 1 and Fig. 2, and in first to the 3rd embodiment of the present invention, described light shield is metal level or contact hole layer light shield; Described aerial image alignment marker graphic 10 is that a length of side is 15 microns a square; Described auxiliary striped 11 is that a width is 2 to 6 microns rectangular; Described each aerial image alignment marker graphic 10 outside are symmetrically arranged with four layers of auxiliary striped 11, first and second layers of auxiliary striped are made up of four auxiliary strips 11, and third and fourth layer of auxiliary striped all only is made up of two that are arranged in aerial image alignment marker graphic 10 left and right sides auxiliary strips 11; The center of this first to fourth layer of auxiliary striped all overlaps with the center of aerial image alignment marker graphic 10.In other embodiments of the invention, described aerial image alignment marker graphic 10 can be the inside casing length of side greater than 20 microns square frame.
With space imaging overlay mark figure in the prior art the auxiliary striped of individual layer only being set on every side compares, be symmetrically arranged with the auxiliary striped 11 of multilayer in each aerial image alignment marker graphic 10 outside on the light shield that improves aerial image alignment checking precision degree of the present invention, increased the pattern density of aerial image alignment marker graphic 10 greatly.
It should be noted that, the number of plies of auxiliary striped 11 needs to determine (to be simplicity of illustration and explanation according to the next reality of the concrete width of Cutting Road (Scribelane), in Fig. 1, Cutting Road is not illustrated), when the Cutting Road wider width and when being 75 microns, the number of plies of auxiliary striped 11 can be greater than four layers, and is narrower and when being 25 microns, the number of plies of auxiliary striped 11 can only be two-layer when the Cutting Road width.
The photoetching method that improves aerial image alignment checking precision degree of the present invention is used for the figure transfer on the light shield as shown in Figure 1 to the photoresist that is coated on the silicon substrate, referring to Fig. 3, the photoetching method that improves aerial image alignment checking precision degree of the present invention at first carries out step S30, on described silicon substrate, be coated with photoresist, wherein, described photoresist is a positive photoresist.In first to the 3rd embodiment of the present invention, described positive photoresist comprises solvent, resin and Photoactive compounds.
Then continue step S31, carry out temperature range and be 115 to 125 degrees centigrade preceding baking technology.In first to the 3rd embodiment of the present invention, the temperature of described preceding baking technology is respectively 115,120 and 125 degrees centigrade.
Then continue step S32, use described light shield to carry out exposure technology so that the aerial image alignment marker graphic on the light shield is transferred on the described photoresist.In first to the 3rd embodiment of the present invention, the aerial image alignment marker graphic 10 and the auxiliary striped 11 that are about to are as shown in Figure 1 transferred on the described photoresist.
Then continue step S33, carry out developing process.In first to the 3rd embodiment of the present invention, chemical reaction takes place by developer solution and aerial image alignment marker graphic 10 and auxiliary striped 11 corresponding exposure areas, thereby the photoresist that will carry described aerial image alignment marker graphic 10 and auxiliary striped 11 remains, and remaining photoresist is removed.
Then continue step S34, carry out back baking technology, the temperature range of described back baking technology is 85 to 95 degrees centigrade.In first to the 3rd embodiment of the present invention, the temperature of described back baking technology is respectively 85,90 and 95 degrees centigrade, and behind the completing steps S34, the thickness of photoresist is 4 to 5 microns.
After after finishing, drying by the fire technology, can under the covering of the photoresist of the photoresist of carrying described aerial image alignment marker graphic 10 and auxiliary striped 11, carry out etching technics, remove photoresist then and in the aerial image alignment checking board, carry out aerial image alignment checking according to the formed imaging overlay mark of etching.
Experimental data proves, use the described aerial image alignment marker graphic of carrying that first to the 3rd embodiment that improves the photoetching method of aerial image alignment checking precision degree of the present invention makes by lithography and compare with the formed photoresist of photoetching method that uses prior art as the photoresist of subsequent etching technology, the slope at its edge and the unevenness on slope significantly improve, for example with the formed photoresist margin slope of photoetching method in the prior art by being reduced into less than 50 nanometers greater than 200 nanometers.
In sum, the light shield of aerial image alignment checking precision degree that improves of the present invention is by being provided with the auxiliary striped that multilayer is used to increase its pattern density around the aerial image alignment marker graphic, it is 115 to 125 degrees centigrade that photoetching method of the present invention uses described light shield to carry out photoetching and the temperature of baking technology before described is brought up to by 90 degrees centigrade, so can reduce the slope of the photoresist of the described aerial image alignment marker graphic of carrying greatly, and improve its homogeneity greatly, and then can improve the precision of aerial image alignment checking greatly.
Claims (9)
1. the light shield that can improve aerial image alignment checking precision degree has a plurality of aerial image alignment marker graphics on this light shield, it is characterized in that, is provided with the auxiliary striped that multilayer is used to increase its pattern density around this aerial image alignment marker graphic.
2. the light shield that improves aerial image alignment checking precision degree as claimed in claim 1 is characterized in that, this aerial image alignment marker graphic is a square.
3. the light shield that improves aerial image alignment checking precision degree as claimed in claim 1 is characterized in that, the center of the auxiliary striped of this each layer overlaps with the center of this aerial image alignment marker graphic.
4. one kind is used the photoetching method that improves the light shield of aerial image alignment checking precision degree as claimed in claim 1, be used for the figure transfer on this light shield to the photoresist that is coated on the silicon substrate, this method may further comprise the steps: a, coating photoresist step on this silicon substrate; B, carry out before the baking processing step; C, use this light shield to carry out exposure technology so that the aerial image alignment marker graphic on it is transferred to step on this photoresist; D, carry out the developing process step; E, carry out back baking processing step; It is characterized in that in step b, temperature range of baking technology is 115 to 125 degrees centigrade before this.
5. the photoetching method that improves aerial image alignment checking precision degree as claimed in claim 4 is characterized in that, behind completing steps e, the thickness of this photoresist is 4 to 5 microns.
6. the photoetching method that improves aerial image alignment checking precision degree as claimed in claim 4 is characterized in that, in step a, this photoresist is a positive photoresist.
7. the photoetching method that improves aerial image alignment checking precision degree as claimed in claim 6 is characterized in that this positive photoresist comprises solvent, resin and Photoactive compounds.
8. the photoetching method that improves aerial image alignment checking precision degree as claimed in claim 4 is characterized in that, in step b, temperature of baking technology is 120 degrees centigrade before this.
9. the photoetching method that improves aerial image alignment checking precision degree as claimed in claim 4 is characterized in that, in step e, the temperature range of this back baking technology is 85 to 95 degrees centigrade.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007101705419A CN101158808A (en) | 2007-11-16 | 2007-11-16 | Light shield capable of improving aerial image alignment checking precision degree and photolithography method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007101705419A CN101158808A (en) | 2007-11-16 | 2007-11-16 | Light shield capable of improving aerial image alignment checking precision degree and photolithography method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101158808A true CN101158808A (en) | 2008-04-09 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2007101705419A Pending CN101158808A (en) | 2007-11-16 | 2007-11-16 | Light shield capable of improving aerial image alignment checking precision degree and photolithography method |
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| CN (1) | CN101158808A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102799062A (en) * | 2012-08-29 | 2012-11-28 | 上海宏力半导体制造有限公司 | Mask, wafer and monitor method |
| CN108417562B (en) * | 2018-03-19 | 2019-04-26 | 长江存储科技有限责任公司 | Overlay mark and its reliability verification method |
| CN114935877A (en) * | 2022-05-24 | 2022-08-23 | 上海华力集成电路制造有限公司 | An auxiliary pattern design method for improving photoresist morphology asymmetry |
-
2007
- 2007-11-16 CN CNA2007101705419A patent/CN101158808A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102799062A (en) * | 2012-08-29 | 2012-11-28 | 上海宏力半导体制造有限公司 | Mask, wafer and monitor method |
| CN108417562B (en) * | 2018-03-19 | 2019-04-26 | 长江存储科技有限责任公司 | Overlay mark and its reliability verification method |
| CN114935877A (en) * | 2022-05-24 | 2022-08-23 | 上海华力集成电路制造有限公司 | An auxiliary pattern design method for improving photoresist morphology asymmetry |
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Open date: 20080409 |