CN101369571A - Semiconductor device, wafer coarse alignment mark and coarse alignment method - Google Patents
Semiconductor device, wafer coarse alignment mark and coarse alignment method Download PDFInfo
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- CN101369571A CN101369571A CNA2007100450323A CN200710045032A CN101369571A CN 101369571 A CN101369571 A CN 101369571A CN A2007100450323 A CNA2007100450323 A CN A2007100450323A CN 200710045032 A CN200710045032 A CN 200710045032A CN 101369571 A CN101369571 A CN 101369571A
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Abstract
The invention discloses a wafer coarse alignment mark, comprising: a first structure and a second structure distributed around the first structure; the first structure is in a shape of cross, the second structure comprises four groups of gratings in which two adjacent groups of gratings are perpendicular to one another. The invention also discloses a semiconductor device and a coarse alignment method. The inventive semiconductor device, wafer coarse alignment mark and coarse alignment method strengthen success ratio of precise alignment on account of addressing the problem of failing to precisely align the wafers after the coarse alignment in the prior art.
Description
Technical field
The present invention relates to photoetching process, particularly the semiconductor device in the photoetching process, wafer coarse alignment mark and coarse alignment method.
Background technology
Along with the development of semiconductor technology, the area of semiconductor chip is more and more littler, and the live width in the chip is also constantly dwindled, so the test that the semiconductor technology ability is subjected to is also increasing, and the control of the precision of technology and technology variation also becomes more important.In the technology of making semiconductor chip, most important technical process is exactly photoetching, described photoetching promptly is by series of steps such as aligning, exposure, etchings mask pattern to be transferred to technical process on the wafer, so the quality of photoetching process can directly have influence on the performance of final formation chip.
At present, the device that is used for photoetching mainly contains two kinds, a kind of is the stepping lithographic equipment, the mask pattern single exposure is imaged on an exposure area of wafer, wafer moves with respect to mask subsequently, next exposure area is moved to reticle pattern and projection objective below, again mask pattern is exposed in another exposure area of wafer, repeat the picture that this process all exposure areas on wafer all have mask pattern.And another kind is the step-scan lithographic equipment, and in above-mentioned exposure process, mask pattern is not the single exposure imaging, but the scanning mobile imaging by the projection light field.In the mask pattern imaging process, mask and wafer move with respect to optical projection system and projected light beam simultaneously.
In photoetching process, correctly to transfer on the wafer for making mask pattern, critical step is with mask and wafer alignment, promptly calculates the position of mask with respect to wafer, to satisfy the requirement of alignment precision.When characteristic size more and more hour, also more and more higher to the requirement of alignment precision and consequent requirement to alignment precision.And said lithography alignment technology generally is divided into coarse alignment and fine alignment.
Can at first carry out coarse alignment for wafer before wafer is transmitted into lithographic equipment, present coarse alignment method generally all is to carry out coarse alignment by the coarse alignment mark that light sensor is surveyed on the wafer.Coarse alignment mark on the described wafer all is recess or the concave edge at crystal round fringes usually.When carrying out coarse alignment, detecting light beam is opened and sent to light sensor, wafer is placed on the vacuum cup and rotation, when the recess of crystal round fringes or concave edge are positioned at the light sensor top, detecting light beam just in time penetrates from the recess of crystal round fringes or concave edge, this moment, alignment system will think that wafer has reached the coarse alignment position, and wafer can be sent in the lithographic equipment.
And for fine alignment, prior art has two kinds of alignment scheme, and a kind of is the coaxial alignment technology of scioptics, and another kind is the off-axis alignment technology.Before carrying out resist exposure each time, need to use alignment mark to carry out aiming at of mask and wafer.In the off-axis alignment technology, the whole audience alignment mark or the marking groove alignment mark that will be positioned at territory, wafer non-exposed area are imaged onto on the reference plate, position by determining alignment mark is carried out exposing wafer zone and mask pattern and is located with respect to the deviation of the reference marker that is in ideal position.
Fine alignment mainly contains several technology of light field, details in a play not acted out on stage, but told through dialogues and optical grating diffraction.What at present, lithographic equipment adopted mostly is that the fine alignment mode is an optical grating diffraction.Optical grating diffraction is meant that illumination beam on the grating type alignment mark diffraction takes place, and diffraction light carries the full detail about the structure of alignment mark.The multilevel diffraction light scatters from the phase alignment grating with different angles, after filtering zero order light by spatial filter, gather diffraction light ± 1 order diffraction light, the perhaps raising that requires along with characteristic size, gather multi-level diffraction light simultaneously at plane of reference interference imaging, survey and signal processing through photodetector, determine the centring position.
In for example patent No. is to find more information about wafer alignment technology in the United States Patent (USP) of US6139251.
Yet, find that in practice after being transmitted into lithographic equipment, lithographic equipment usually can be owing to the fine alignment mark that can not find on the wafer causes the fine alignment failure, and wafer is withdrawed from, and causes photoetching to proceed through the wafer of coarse alignment.
Summary of the invention
The invention provides a kind of semiconductor device, wafer coarse alignment mark and coarse alignment method, solve prior art photoetching fine alignment and can not find the fine alignment mark and cause fine alignment failure, the problem that causes photoetching to proceed.
For addressing the above problem, the invention provides a kind of semiconductor device, comprise, central area and around the fringe region of central area, wherein said fringe region has wafer coarse alignment mark, wherein, described wafer coarse alignment mark comprises first structure and is distributed in second structure of the first structure periphery, described first structure is cross shape, and described second structure comprises four groups of gratings, and two groups of wherein adjacent gratings are orthogonal.
Described wafer coarse alignment is labeled as the grating groove, and the degree of depth of described grating groove is 1200 to 1400 dusts.
The width of described edge annular section is 3 to 7mm, and described wafer coarse alignment mark is positioned at and departs from the diameter wafer angular range at-20 ° to+20 ° fringe region.
The present invention also provides a kind of wafer coarse alignment mark, comprises,
First structure and second structure that is distributed in the first structure periphery, described first structure is cross shape, and described second structure comprises four groups of optical grating constructions, and two groups of wherein adjacent gratings are orthogonal.
The present invention also provides a kind of coarse alignment method, comprise, wafer with wafer coarse alignment mark is provided,, adjusts wafer position according to comparison result with wafer coarse alignment mark on the wafer and default wafer coarse alignment mark comparison, wherein, described wafer coarse alignment mark comprises, first structure and second structure that is distributed in the first structure periphery, and described first structure is cross shape, described second structure comprises four groups of optical grating constructions, and two groups of wherein adjacent gratings are orthogonal.
Optionally, described four groups of gratings have two kinds of different grating cycles at least.
Optionally, described each group grating is shaped as rectangle.
Optionally, non-conterminous two groups of gratings are that the center is centrosymmetric with first structure in described four groups of gratings.
Optionally, described first structure is the cross hairs form.
Optionally, described first structure cross hairs box form that the cross frame of sealing is formed of serving as reasons.
Optionally, described first structure is the paired-line cross form of being made up of four groups of orthogonal parallel wires.
Compared with prior art, such scheme has the following advantages: the wafer coarse alignment mark that such scheme semiconductor device, wafer coarse alignment mark, coarse alignment method adopt is similar to the alignment mark structure of lithographic equipment calibration usefulness, the wafer coarse alignment mark of this structure can be marked at fine alignment and carry out exposure imaging and etching forming in the front procedure simultaneously, thereby better with the fine alignment mark coupling in the lithographic equipment, thereby the wafer coarse alignment mark of such scheme can improve lithographic equipment finds the fine alignment mark in the fine alignment process success rate.
Description of drawings
Fig. 1 is an embodiment of the invention wafer coarse alignment mark schematic diagram;
Fig. 2 is another wafer coarse alignment mark schematic diagram of the embodiment of the invention;
Fig. 3 is an embodiment of the invention wafer coarse alignment label creating method flow diagram;
Fig. 4 is an embodiment of the invention wafer coarse alignment mark position schematic diagram;
Fig. 5 is an embodiment of the invention coarse alignment method flow diagram;
Fig. 6 is an embodiment of the invention coarse alignment method schematic diagram;
Fig. 7 is an embodiment of the invention wafer alignment method flow diagram;
Fig. 8 is an embodiment of the invention photoetching method flow chart;
Fig. 9 to Figure 13 is an embodiment of the invention photoetching method schematic diagram.
Embodiment
The wafer coarse alignment mark that semiconductor device of the present invention, wafer coarse alignment mark and coarse alignment method adopt is similar to the alignment mark structure of lithographic equipment calibration usefulness, the wafer coarse alignment mark of this structure can be marked at fine alignment and carry out exposure imaging and etching forming in the front procedure simultaneously, thereby better with the fine alignment mark coupling in the lithographic equipment, thereby the wafer coarse alignment mark of such scheme can improve lithographic equipment finds the fine alignment mark in the fine alignment process success rate.
Semiconductor device of the present invention, wafer coarse alignment mark and coarse alignment method are elaborated by preferred embodiment and make wafer coarse alignment mark of the present invention and coarse alignment method clearer.
With reference to shown in Figure 1, embodiment of the invention wafer coarse alignment mark comprises, first structure 10 and second structure that is distributed in first structure, 10 peripheries, described first structure 10 is cross shape, and described second structure comprises the first grating group 21, the second grating group 22, the 3rd grating group 23, the 4th grating group 24.Two groups of adjacent in the wherein said first grating group 21, the second grating group 22, the 3rd grating group 23, the 4th grating group 24 gratings are orthogonal, for example shown in Fig. 1, the grating orientation of the first grating group 21 and the 4th grating group 24 and the vertical direction of paper are consistent, and the grating orientation of the second grating group 22 and the 3rd grating group 21 and the horizontal direction of paper are consistent.
The described first grating group 21 comprises at least 11 gratings, and the grating cycle of described grating is identical, the spacing sum between the live width that the described grating cycle is a grating and two gratings.The described grating cycle is 16um or 17.6um.For example, with the grating cycle is that 16um is an example, if the grating live width is 8 to 8.8um, for example 8um, 8.1um, 8.2um, 8.3um, 8.4um, 8.5um, 8.6um, 8.7um, 8.8um, then spacing is 7.2um to 8um, for example 7.2um, 7.3um, 7.4um, 7.5um, 7.6um, 7.7um, 7.8um, 7.9um, 8um.Described grating length is 168 to 200um, 168um for example, 169um, 170um, 171um, 172um, 173um, 174um, 175um, 176um, 177um, 178um, 179um, 180um, 181um, 182um, 183um, 184um, 185um, 186um, 17um, 188um, 189um, 190um, 191um, 192um, 193um, 194um, 195um, 196um, 197um, 198um, 199um, 200um, described grating in vertical direction, give an example as a kind of of embodiments of the invention, gratings strips number herein is 12, described grating live width is 8um, and described grating space is 8um.The described first grating group 21 be shaped as rectangle.
Described the 3rd grating group 23 comprises at least 11 gratings, and the grating cycle of described grating is identical, the spacing sum between the live width that the described grating cycle is a grating and two gratings.The described grating cycle is 16um or 17.6um.For example, with the grating cycle is that 16um is an example, if the grating live width is 8 to 8.8um, for example 8um, 8.1um, 8.2um, 8.3um, 8.4um, 8.5um, 8.6um, 8.7um, 8.8um, then spacing is 7.2um to 8um, for example 7.2um, 7.3um, 7.4um, 7.5um, 7.6um, 7.7um, 7.8um, 7.9um, 8um.Described grating length is 168 to 200um, for example 168um, 169um, 170um, 171um, 172um, 173um, 174um, 175um, 176um, 177um, 178um, 179um, 180um, 181um, 182um, 183um, 184um, 185um, 186um, 187um, 188um, 189um, 190um, 191um, 192um, 193um, 194um, 195um, 196um, 197um, 198um, 199um, 200um, described grating in horizontal direction, give an example as a kind of of embodiments of the invention, gratings strips number herein is 12.Described grating live width is 8um, and described grating space is 8um.Described the 3rd grating group 23 be shaped as rectangle.
The described second grating group 22 comprises at least 10 gratings, and the grating cycle of described grating is identical, the spacing sum between the live width that the described grating cycle is a grating and two gratings.The described grating cycle is 16um or 17.6um.For example, with the grating cycle is that 17.6um is an example, if the grating live width is 8 to 8.8um, for example 8um, 8.1um, 8.2um, 8.3um, 8.4um, 8.5um, 8.6um, 8.7um, 8.8um, then spacing is 8.8um to 9.6um, for example 8.8um, 8.9um, 9um, 9.1um, 9.2um, 9.3um, 9.4um, 9.5um, 9.6um.Described grating length is 168 to 200um, for example 168um, 169um, 170um, 171um, 172um, 173um, 174um, 175um, 176um, 177um, 178um, 179um, 180um, 181um, 182um, 183um, 184um, 185um, 186um, 187um, 188um, 189um, 190um, 191um, 192um, 193um, 194um, 195um, 196um, 197um, 198um, 199um, 200um, described grating in horizontal direction, give an example as a kind of of embodiments of the invention, gratings strips number herein is 11.Described grating live width is 8.8um, and described grating space is 8.8um.The described second grating group 22 be shaped as rectangle.
Described the 4th grating group 24 comprises at least 10 gratings, and the grating cycle of described grating is identical, the spacing sum between the live width that the described grating cycle is a grating and two gratings.The described grating cycle is 16um or 17.6um.For example, with the grating cycle is that 17.6um is an example, if the grating live width is 8 to 8.8um, for example 8um, 8.1um, 8.2um, 8.3um, 8.4um, 8.5um, 8.6um, 8.7um, 8.8um, then spacing is 8.8um to 9.6um, for example 8.8um, 8.9um, 9um, 9.1um, 9.2um, 9.3um, 9.4um, 9.5um, 9.6um.Described grating length is 168 to 200um, for example 168um, 169um, 170um, 171um, 172um, 173um, 174um, 175um, 176um, 177um, 178um, 179um, 180um, 181um, 182um, 183um, 184um, 185um, 186um, 187um, 188um, 189um, 190um, 191um, 192um, 193um, 194um, 195um, 196um, 197um, 198um, 199um, 200um, described grating in vertical direction, give an example as a kind of of embodiments of the invention, gratings strips number herein is 11.Described grating live width is 8.8um, and described grating space is 8.8um.Described the 4th grating group 24 be shaped as rectangle.
The long limit of the described first grating group 21 is parallel with the broadside of the second grating group 22, the long limit of described the 3rd grating group 23 is parallel with the broadside of the first grating group 21, the long limit of described the 4th grating group 24 is parallel with the broadside of the 3rd grating group 23, and the broadside of described the 4th grating group 24 is parallel with the long limit of the second grating group 22.
Described first grating group 21 and the 4th grating group 24 are that the center is centrosymmetric with first structure 10, and described second grating group 22 and the 3rd grating group 23 are that the center is centrosymmetric with first structure 10.Further, in the described first grating group 21, the second grating group 22, the 3rd grating group 23 and the 4th grating group 24 position of two adjacent groups with the diameter wafer be respectively the axle axisymmetricly.For example, when two cross spiders of the cross shape of first structure 10 are in horizontal direction and vertical direction respectively, the position of the first grating group 21 and the second grating group 22 with the cross spider of first structure 10 that is in vertical direction serve as axle axisymmetricly.The position of the 3rd grating group 23 and the 4th grating group 24 also with the cross spider of first structure 10 that is in vertical direction serve as axle axisymmetricly.The position of the first grating group 21 and the second grating group 23 with the cross spider of first structure 10 that is in horizontal direction serve as axle axisymmetricly.The position of the 3rd grating group 22 and the 4th grating group 24 also with the cross spider of first structure 10 that is in horizontal direction serve as axle axisymmetricly.
The size of described wafer coarse alignment mark is relevant with the size of wafer coarse alignment mark present position and wafer coarse alignment mark wafer of living in, wafer with 200mm is an example, wafer coarse alignment mark should satisfy and can not enter in the 32.5mm of crystal circle center scope, wafer coarse alignment mark need be positioned at the annular section from crystal circle center's 32.5 to 97mm scopes, for example is positioned at the 32.5mm from crystal circle center, 34mm, 36mm, 38mm, 40mm, 42mm, 44mm, 46mm, 48mm, 50mm, 52mm, 54mm, 56mm, 58mm, 60mm, 62mm, 64mm, 66mm, 68mm, 70mm, 72mm, 74mm, 76mm, 78mm, 80mm, 82mm, 84mm, 86mm, 88mm, 90mm, 92mm, 94mm, in the annular section of 97mm.Further, wafer coarse alignment mark is positioned at the annular section from crystal round fringes 3 to 7mm, for example is positioned at the annular section from crystal round fringes 3.0mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4.0mm, 4.2mm, 4.4mm, 4.6mm, 4.8mm, 5.0mm, 5.2mm, 5.4mm, 5.6mm, 5.8mm, 6mm, 6.2mm, 6.4mm, 6.6mm, 6.8mm, 7mm.Give an example as a kind of of the embodiment of the invention, described first structure 10 is labeled as the long 413um that is with the wafer coarse alignment that second structure that is distributed in first structure, 10 peripheries constitutes, and wide is the rectangle of 413um.Further, owing to be to rely on image recognition to reach the coarse alignment purpose when carrying out coarse alignment for described wafer coarse alignment mark, thereby any other graphic structure that in the scope of described wafer coarse alignment mark periphery ± 98.5um, do not have, be that the total area occupied of wafer coarse alignment mark is the long 610um of being, wide is the rectangular area of 610um, to avoid influencing the coarse alignment process.
The distance on the long limit of the broadside of the described first grating group 21 and the 3rd grating group 23 is 26 to 84um, for example 26um, 28um, 30um, 32um, 34um, 36um, 38um, 40um, 42um, 45um, 48um, 50um, 52um, 54um, 56um, 58um, 60um, 62um, 64um, 66um, 68um, 70um, 72um, 74um, 76um, 78um, 80um, 82um, 84um, give an example as a kind of of the embodiment of the invention, described distance is 45um.
The distance of the long limit of the described first grating group 21 and the broadside of the second grating group 22 is 26 to 84um, for example 26um, 28um, 30um, 32um, 34um, 36um, 38um, 40um, 42um, 45um, 48um, 50um, 52um, 54um, 56um, 58um, 60um, 62um, 64um, 66um, 68um, 70um, 72um, 74um, 76um, 78um, 80um, 82um, 84um, give an example as a kind of of the embodiment of the invention, described distance is 45um.
The distance on the long limit of the broadside of described the 3rd grating group 23 and the 4th grating group 24 is 26 to 84um, for example 26um, 28um, 30um, 32um, 34um, 36um, 38um, 40um, 42um, 45um, 48um, 50um, 52um, 54um, 56um, 58um, 60um, 62um, 64um, 66um, 68um, 70um, 72um, 74um, 76um, 78um, 80um, 82um, 84um, give an example as a kind of of the embodiment of the invention, described distance is 45um.
The distance on the long limit of the broadside of the described second grating group 22 and the 4th grating group 24 is 26 to 84um, for example 26um, 28um, 30um, 32um, 34um, 36um, 38um, 40um, 42um, 45um, 48um, 50um, 52um, 54um, 56um, 58um, 60um, 62um, 64um, 66um, 68um, 70um, 72um, 74um, 76um, 78um, 80um, 82um, 84um, give an example as a kind of of the embodiment of the invention, described distance is 45um.
Described first structure 10 can be the cross hairs form, the described first structure 10 cross hairs box form that the cross frame of sealing is formed of also can serving as reasons, and described first structure 10 also can be the paired-line cross form of being made up of four groups of orthogonal parallel wires.
With reference to shown in Figure 2, the another kind of alignment mark of the embodiment of the invention comprises, first structure 10 and second structure that is distributed in first structure, 10 peripheries, described first structure 10 is cross shape, and described second structure comprises the first grating group 21, the second grating group 22, the 3rd grating group 23, the 4th grating group 24.Two groups of adjacent in the wherein said first grating group 21, the second grating group 22, the 3rd grating group 23, the 4th grating group 24 gratings are orthogonal.For example shown in Figure 2, the grating orientation of the first grating group 21 and the 4th grating group 24 and the horizontal direction of paper are consistent, and the grating orientation of the second grating group 22 and the 3rd grating group 23 and the vertical direction of paper are consistent.
The described first grating group 21 comprises at least 10 gratings, and the grating cycle of described grating is identical, the spacing sum between the live width that the described grating cycle is a grating and two gratings.The described grating cycle is 16um or 17.6um.For example, with the grating cycle is that 17.6um is an example, if the grating live width is 8 to 8.8um, for example 8um, 8.1um, 8.2um, 8.3um, 8.4um, 8.5um, 8.6um, 8.7um, 8.8um, then spacing is 8.8um to 9.6um, for example 8.8um, 8.9um, 9um, 9.1um, 9.2um, 9.3um, 9.4um, 9.5um, 9.6um.Described grating length is 168 to 200um, for example 168um, 169um, 170um, 171um, 172um, 173um, 174um, 175um, 176um, 177um, 178um, 179um, 180um, 181um, 182um, 183um, 184um, 185um, 186um, 187um, 188um, 189um, 190um, 191um, 192um, 193um, 194um, 195um, 196um, 197um, 198um, 199um, 200um, described grating in horizontal direction, give an example as a kind of of embodiments of the invention, gratings strips number herein is 11.Described grating live width is 8.8um, and described grating space is 8.8um.The described first grating group 21 be shaped as rectangle.
Described the 3rd grating group 23 comprises at least 10 gratings, and the grating cycle of described grating is identical, the spacing sum between the live width that the described grating cycle is a grating and two gratings.The described grating cycle is 16um or 17.6um.For example, with the grating cycle is that 17.6um is an example, if the grating live width is 8 to 8.8um, for example 8um, 8.1um, 8.2um, 8.3um, 8.4um, 8.5um, 8.6um, 8.7um, 8.8um, then spacing is 8.8um to 9.6um, for example 8.8um, 8.9um, 9um, 9.1um, 9.2um, 9.3um, 9.4um, 9.5um, 9.6um.Described grating length is 168 to 200um, for example 168um, 169um, 170um, 171um, 172um, 173um, 174um, 175um, 176um, 177um, 178um, 179um, 180um, 181um, 182um, 183um, 184um, 185um, 186um, 187um, 188um, 189um, 190um, 191um, 192um, 193um, 194um, 195um, 196um, 197um, 198um, 199um, 200um, described grating in vertical direction, give an example as a kind of of embodiments of the invention, gratings strips number herein is 11.Described grating live width is 8.8um, and described grating space is 8.8um.Described the 3rd grating group 23 be shaped as rectangle.
The described second grating group 22 comprises at least 11 gratings, and the grating cycle of described grating is identical, the spacing sum between the live width that the described grating cycle is a grating and two gratings.The described grating cycle is 16um or 17.6um.For example, with the grating cycle is that 16um is an example, if the grating live width is 8 to 8.8um, for example 8um, 8.1um, 8.2um, 8.3um, 8.4um, 8.5um, 8.6um, 8.7um, 8.8um, then spacing is 7.2um to 8um, for example 7.2um, 7.3um, 7.4um, 7.5um, 7.6um, 7.7um, 7.8um, 7.9um, 8um.Described grating length is 168 to 200um, for example 168um, 169um, 170um, 171um, 172um, 173um, 174um, 175um, 176um, 177um, 178um, 179um, 180um, 181um, 182um, 183um, 184um, 185um, 186um, 187um, 188um, 189um, 190um, 191um, 192um, 193um, 194um, 195um, 196um, 197um, 198um, 199um, 200um, described grating in vertical direction, give an example as a kind of of embodiments of the invention, gratings strips number herein is 12.Described grating live width is 8um, and described grating space is 8um.The described second grating group 22 be shaped as rectangle.
Described the 4th grating group 24 comprises at least 11 gratings, and the grating cycle of described grating is identical, the spacing sum between the live width that the described grating cycle is a grating and two gratings.The described grating cycle is 16um or 17.6um.For example, with the grating cycle is that 16um is an example, if the grating live width is 8 to 8.8um, for example 8um, 8.1um, 8.2um, 8.3um, 8.4um, 8.5um, 8.6um, 8.7um, 8.8um, then spacing is 7.2um to 8um, for example 7.2um, 7.3um, 7.4um, 7.5um, 7.6um, 7.7um, 7.8um, 7.9um, 8um.Described grating length is 168 to 200um, for example 168um, 169um, 170um, 171um, 172um, 173um, 174um, 175um, 176um, 177um, 178um, 179um, 180um, 181um, 182um, 183um, 184um, 185um, 186um, 187um, 188um, 189um, 190um, 191um, 192um, 193um, 194um, 195um, 196um, 197um, 198um, 199um, 200um, described grating in horizontal direction, give an example as a kind of of embodiments of the invention, gratings strips number herein is 12.Described grating live width is 8um, and described grating space is 8um.Described the 4th grating group 24 be shaped as rectangle.
The broadside of the described first grating group 21 is parallel with the long limit of the second grating group 22, the broadside of the described second grating group 22 is parallel with the long limit of the 4th grating group 24, the broadside of described the 4th grating group 24 is parallel with the long limit of the 3rd grating group 23, and the broadside of described the 3rd grating group 23 is parallel with the long limit of the first grating group 21.
Described first grating group 21 and the 4th grating group 24 are that the center is centrosymmetric with first structure 10, and described second grating group 22 and the 3rd grating group 23 are that the center is centrosymmetric with first structure 10.Further, in the described first grating group 21, the second grating group 22, the 3rd grating group 23 and the 4th grating group 24 position of two adjacent groups with the diameter wafer be respectively the axle axisymmetricly.For example, when two cross spiders of the cross shape of first structure 10 are in horizontal direction and vertical direction respectively, the position of the first grating group 21 and the second grating group 22 with the cross spider of first structure 10 that is in vertical direction serve as axle axisymmetricly.The position of the 3rd grating group 23 and the 4th grating group 24 also with the cross spider of first structure 10 that is in vertical direction serve as axle axisymmetricly.The position of the first grating group 21 and the second grating group 23 with the cross spider of first structure 10 that is in horizontal direction serve as axle axisymmetricly.The position of the 3rd grating group 22 and the 4th grating group 24 also with the cross spider of first structure 10 that is in horizontal direction serve as axle axisymmetricly.
The size of described wafer coarse alignment mark is relevant with the size of wafer coarse alignment mark present position and wafer coarse alignment mark wafer of living in, wafer with 200mm is an example, wafer coarse alignment mark should satisfy and can not enter in the 32.5mm of crystal circle center scope, wafer coarse alignment mark need be positioned at the annular section from crystal circle center's 32.5 to 97mm scopes, for example is positioned at the 32.5mm from crystal circle center, 34mm, 36mm, 38mm, 40mm, 42mm, 44mm, 46mm, 48mm, 50mm, 52mm, 54mm, 56mm, 58mm, 60mm, 62mm, 64mm, 66mm, 68mm, 70mm, 72mm, 74mm, 76mm, 78mm, 80mm, 82mm, 84mm, 86mm, 88mm, 90mm, 92mm, 94mm, in the annular section of 97mm.Further, wafer coarse alignment mark is positioned at the annular section from crystal round fringes 3 to 7mm, for example is positioned at the annular section from crystal round fringes 3.0mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4.0mm, 4.2mm, 4.4mm, 4.6mm, 4.8mm, 5.0mm, 5.2mm, 5.4mm, 5.6mm, 5.8mm, 6mm, 6.2mm, 6.4mm, 6.6mm, 6.8mm, 7mm.Give an example as a kind of of the embodiment of the invention, described first structure 10 is labeled as the long 413um that is with the wafer coarse alignment that second structure that is distributed in first structure, 10 peripheries constitutes, and wide is the rectangle of 413um.Further, owing to be to rely on image recognition to reach the coarse alignment purpose when carrying out coarse alignment for described wafer coarse alignment mark, thereby any other graphic structure that in the scope of described wafer coarse alignment mark periphery ± 98.5um, do not have, be that the total area occupied of wafer coarse alignment mark is the long 610um of being, wide is the rectangular area of 610um, to avoid influencing the coarse alignment process.
The distance on the long limit of the broadside of the described first grating group 21 and the second grating group 22 is 26 to 84um, for example 26um, 28um, 30um, 32um, 34um, 36um, 38um, 40um, 42um, 45um, 48um, 50um, 52um, 54um, 56um, 58um, 60um, 62um, 64um, 66um, 68um, 70um, 72um, 74um, 76um, 78um, 80um, 82um, 84um, give an example as a kind of of the embodiment of the invention, described distance is 45um.
The distance of the long limit of the described first grating group 21 and the broadside of the 3rd grating group 23 is 26 to 84um, for example 26um, 28um, 30um, 32um, 34um, 36um, 38um, 40um, 42um, 45um, 48um, 50um, 52um, 54um, 56um, 58um, 60um, 62um, 64um, 66um, 68um, 70um, 72um, 74um, 76um, 78um, 80um, 82um, 84um, give an example as a kind of of the embodiment of the invention, described distance is 45um.
The distance of the long limit of described the 3rd grating group 23 and the broadside of the 4th grating group 24 is 26 to 84um, for example 26um, 28um, 30um, 32um, 34um, 36um, 38um, 40um, 42um, 45um, 48um, 50um, 52um, 54um, 56um, 58um, 60um, 62um, 64um, 66um, 68um, 70um, 72um, 74um, 76um, 78um, 80um, 82um, 84um, give an example as a kind of of the embodiment of the invention, described distance is 45um.
The distance on the long limit of the broadside of the described second grating group 22 and the 4th grating group 24 is 26 to 84um, for example 26um, 28um, 30um, 32um, 34um, 36um, 38um, 40um, 42um, 45um, 48um, 50um, 52um, 54um, 56um, 58um, 60um, 62um, 64um, 66um, 68um, 70um, 72um, 74um, 76um, 78um, 80um, 82um, 84um, give an example as a kind of of the embodiment of the invention, described distance is 45um.
Described first structure 10 can be the cross hairs form, the described first structure 10 cross hairs box form that the cross frame of sealing is formed of also can serving as reasons, and described first structure 10 also can be the paired-line cross form of being made up of four groups of orthogonal parallel wires.
With reference to shown in Figure 3, the wafer coarse alignment label creating method of the embodiment of the invention comprises the steps,
Step s1 provides the surface to have the wafer of photoresist layer.All be to use the method for photoetching owing on each layer of material of wafer, form component graphics, and before photoetching, must need wafer is aimed at.So used photoresist layer is identical when used photoresist layer and photoetching when making the coarse alignment mark.Generally all be to form described photoresist layer by on wafer, being coated with the last layer photoresist equably.The method of conventional gluing has brush method, spin coating method and infusion method etc.Wherein, a kind of method of smearing photoresist of optimizing is dynamically to spray the gluing method, before resist coating, wafer can be attracted on the sucker and with lower rotating speed, 500rpm low speed rotation for example, afterwards, crystal column surface is constantly exported and be sprayed to photoresist by transmission pipeline.The effect of low speed rotation is to help the initial even diffusion of photoresist.After photoresist extended, sucker will drive the wafer high speed rotating and finish final photoresist expansion, thereby obtained thin and uniform photoresist film.
Step s2 is for the photoresist layer exposure imaging formation photoresist layer opening of crystal column surface.The process of this step also with conventional lithography step in the method for exposure imaging identical.The mask that will have embodiment of the invention alignment mark figure places the wafer top, for example using then, high-pressure mercury lamp, excimer laser, X ray or electron beam etc. expose as the photoresist layer of exposure light source for crystal column surface, make the photoresist layer of exposure area and exposure light source produce photochemical reaction and become and dissolve in developer solution, use wet development then, usually all be to use developer solution, for example TMAH (tetramethyl aqua ammonia) or Acetone (acetone), the photoresist layer of chemical reaction takes place in removal after exposing, and then forms the photoresist layer opening.
Step s3 is a mask with the photoresist layer, carries out etching at described photoresist layer aperture position for wafer.The process of this step also with conventional lithography step in engraving method identical, and select corresponding engraving method for use according to the difference of the residing material layer of alignment mark.For example, on polysilicon layer, form alignment mark, be applicable to that then the method for etching polysilicon just can be used as the method for etching generation alignment mark on polysilicon layer.Through after the etching, crystal column surface has just formed and the corresponding grating groove of alignment mark figure.
With reference to shown in Figure 4, the semiconductor device of the embodiment of the invention comprises central area 200 and around the fringe region 201 of central area 200, wherein said fringe region 201 has wafer coarse alignment mark, wherein, described wafer coarse alignment mark comprises first structure and is distributed in second structure of the first structure periphery, described first structure is cross shape, and described second structure comprises four groups of gratings, and two groups of wherein adjacent gratings are orthogonal.
Described wafer coarse alignment mark is positioned at the annular section of crystal round fringes 3 to 7mm, for example is positioned at the annular section from crystal round fringes 3.0mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4.0mm, 4.2mm, 4.4mm, 4.6mm, 4.8mm, 5.0mm, 5.2mm, 5.4mm, 5.6mm, 5.8mm, 6mm, 6.2mm, 6.4mm, 6.6mm, 6.8mm, 7mm.
Described wafer coarse alignment is labeled as the grating groove, and for the consideration of the accuracy of identification aspect of alignment mark, the degree of depth of normal light grid recess is dark more, and the signal fusing accuracy is then good more.But the degree of depth of the grating groove that can make at present must be subjected to the processing procedure restriction, being formed on the polysilicon layer with the grating groove is example, the degree of depth of groove be 1200 dusts to 1400 dusts, for example 1200 dusts, 1210 dusts, 1220 dusts, 1230 dusts, 1240 dusts, 1250 dusts, 1260 dusts, 1270 dusts, 1280 dusts, 1290 dusts, 1300 dusts, 1310 dusts, 1320 dusts, 1330 dusts, 1340 dusts, 1350 dusts, 1360 dusts, 1370 dusts, 1380 dusts, 1390 dusts, 1400 dusts.
Further, described wafer coarse alignment mark is positioned at and departs from through the horizontal diameter of crystal circle center or the perpendicular diameter angular range annular section at-20 ° to+20 °, for example departs from through the horizontal diameter of crystal circle center or perpendicular diameter angular range at-20 °,-19 °,-18 °,-17 °,-16 °,-15 °,-14 °,-13 °,-12 °,-11 °,-10 °,-9 °,-8 °,-7 °,-6 °,-5 °,-4 °,-3 °,-2 °,-1 °, 0 °, + 1 °, + 2 °, + 3 °, + 4 °, + 5 °, + 6 °, + 7 °, + 8 °, + 9 °, + 10 °, + 11 °, + 12 °, + 13 °, + 14 °, + 15 °, + 16 °, + 17 °, + 18 °, + 19 °, in the annular section of+20 ° crystal round fringes 3 to 7mm.
Further, described wafer coarse alignment mark is to use in pairs, and one group (two wafer coarse alignment marks) or two groups (four wafer coarse alignment marks) can be set on wafer.When one group of wafer coarse alignment mark only is set, can crystal circle center be that the axle center keeps the center symmetry also so that two wafer coarse alignment marks are a retainer shaft symmetry with described vertical direction diameter or horizontal direction diameter through crystal circle center.And when using two groups of wafer coarse alignment marks, the method to set up that the setting of described two groups of wafer coarse alignment marks can be when only using one group of wafer coarse alignment mark.But a kind of implementation as example of the present invention, when using two groups of wafer coarse alignment marks, wherein one group is positioned at through the extended line of the vertical direction diameter of crystal circle center and satisfies annular section at crystal round fringes 3 to 7mm simultaneously for axle ± 5 ° scope, and is a retainer shaft symmetry with the diameter through the horizontal direction of crystal circle center.Another group also is positioned at through the extended line of the vertical direction diameter of crystal circle center and satisfies annular section at crystal round fringes 3 to 7mm simultaneously for axle ± 8 ° scope, and is that the axle center keeps the center symmetry with the crystal circle center.Wherein, satisfy simultaneously in the annular section of crystal round fringes 3 to 7mm in axle ± 5 ° of scopes, and serve as that the axisymmetric one group of coarse alignment of axle maintenance is labeled as good with diameter through the horizontal direction of crystal circle center through the extended line of the vertical direction diameter of crystal circle center.
With reference to shown in Figure 5, the coarse alignment method of the embodiment of the invention comprises the following steps,
Step s10 provides the wafer with wafer coarse alignment mark;
Step s11 is with wafer coarse alignment mark on the wafer and default wafer coarse alignment mark comparison;
Step s12 adjusts wafer position according to comparison result.
In conjunction with Fig. 5 and shown in Figure 6, provide wafer 2 with wafer coarse alignment mark.When carrying out coarse alignment for wafer 2, wafer 2 is placed on the rotary-tray 1, rotary-tray 1 drives wafer 2 rotations, and camera head 3 is opened.Store any of two kinds of above-mentioned wafer coarse alignment marks in the camera head 3.
In conjunction with Fig. 5 and shown in Figure 6, with wafer coarse alignment mark on the wafer 2 and default wafer coarse alignment mark comparison.When rotary-tray 1 drove wafer 2 rotations, camera head 3 can be caught the figure on the wafer 2, and the default wafer coarse alignment mark of storing with self is compared.For example, when the fringe region on the wafer 2 that comprises wafer coarse alignment mark turned to the below of camera head 3, camera head 3 captured wafer coarse alignment mark, and the default wafer coarse alignment mark of storing with self is compared.Set the error range of coarse alignment in the embodiment of the invention.The line-spacing error range of coarse alignment be wafer coarse alignment mark that camera head 3 the captures distance that departs from the default wafer coarse alignment mark of being stored for-1um to+1um, the distance that for example departs from the default wafer coarse alignment mark of being stored for ± 0.1um, ± 0.2um, ± 0.3um, ± 0.4um, ± 0.5um, ± 0.6um, ± 0.7um, ± 0.8um, ± 0.9um, ± 1um.The angular error scope of coarse alignment be wafer coarse alignment mark that camera head 3 the captures angle that departs from the default wafer coarse alignment mark of being stored for-0.1mrad to+0.1mrad, for example ± 0.01mrad, ± 0.02mrad, ± 0.03mrad, ± 0.04mrad, ± 0.05mrad, ± 0.06mrad, ± 0.07mrad, ± 0.08mrad, ± 0.09mrad, ± 0.1mrad.
In conjunction with Fig. 5 and shown in Figure 6, adjust wafer 2 positions according to comparison result.After camera head 3 is with wafer coarse alignment mark that captures and the default wafer coarse alignment mark comparison of self storing, if the deviation of the wafer coarse alignment mark that captures and the wafer coarse alignment mark of self storing is above described error range, then can make adjustment deviation up to wafer coarse alignment mark that is captured and the wafer coarse alignment mark self stored in described error range for the position of wafer.General coarse alignment be subjected to the hardware designs searching scope restriction of camera head 3 apart from adjusting range and angle adjustment scope.
In the embodiment of the invention, coarse alignment apart from adjusting range for adjust basic point be central point-200um is to+200um, distance range, for example the scope adjusted of distance be ± 20um, ± 40um, ± 60um, ± 80um, ± 100um, ± 120um, ± 140um, ± 160um, ± 180um, ± 200um.And the angle adjustment scope of coarse alignment for adjust basic point be central point-4mrad is to+4mrad, for example the scope of angle adjustment be ± 0.2mrad, ± 0.4mrad, ± 0.6mrad, ± 0.8mrad, ± 1mrad, ± 1.2mrad, ± 1.4mrad, ± 1.6mrad, ± 1.8mrad, ± 2mrad, ± 2.2mrad, ± 2.4mrad, ± 2.6mrad, ± 2.8mrad, ± 3mrad, ± 3.2mrad, ± 3.4mrad, ± 3.6mrad, ± 3.8mrad, ± 4mrad.If the deviation of the wafer coarse alignment mark that captures and the default wafer coarse alignment mark self stored is in described error range, then coarse alignment is finished, and wafer can be admitted in the lithographic equipment.If coarse alignment failure, at this moment can be by repeating coarse alignment once more, perhaps directly change not on the same group the mode of coarse alignment mark and come retry.
The coarse alignment method of the embodiment of the invention also can be applicable to wafer alignment, and with reference to shown in Figure 7, described wafer alignment method comprises the following steps,
Step s20, according to the wafer coarse alignment mark on the wafer to the wafer coarse alignment;
Step s21, according to through the fine alignment mark on the wafer of coarse alignment to the wafer fine alignment.
In conjunction with Fig. 6 and shown in Figure 7, according to the wafer coarse alignment mark on the wafer 2 to wafer 2 coarse alignments.When carrying out coarse alignment for wafer 2, wafer 2 is placed on the rotary-tray 1, rotary-tray 1 drives wafer 2 rotations, and camera head 3 is opened.Store any of two kinds of above-mentioned wafer coarse alignment marks in the camera head 3.
When rotary-tray 1 drove wafer 2 rotations, camera head 3 can be caught the figure on the wafer 2, and the default wafer coarse alignment mark of storing with self is compared.When wafer 2 zones that comprise wafer coarse alignment mark turned to the below of camera head 3, camera head 3 captured wafer coarse alignment mark, and the default wafer coarse alignment mark of storing with self is compared.Set the error range of coarse alignment in the embodiment of the invention.The line-spacing error range of coarse alignment be wafer coarse alignment mark that camera head 3 the captures distance that departs from the default wafer coarse alignment mark of being stored for-1um to+1um, the distance that for example departs from the default wafer coarse alignment mark of being stored for ± 0.1um, ± 0.2um, ± 0.3um, ± 0.4um, ± 0.5um, ± 0.6um, ± 0.7um, ± 0.8um, ± 0.9um, ± 1um.The angular error scope of coarse alignment be wafer coarse alignment mark that camera head 3 the captures angle that departs from the default wafer coarse alignment mark of being stored for-0.1mrad to+0.1mrad, for example ± 0.01mrad, ± 0.02mrad, ± 0.03mrad, ± 0.04mrad, ± 0.05mrad, ± 0.06mrad, ± 0.07mrad, ± 0.08mrad, ± 0.09mrad, ± 0.1mrad.
After camera head 3 is with wafer coarse alignment mark that captures and the default wafer coarse alignment mark comparison of self storing, if the deviation of the wafer coarse alignment mark that captures and the wafer coarse alignment mark of self storing is above described error range, then can make adjustment deviation up to wafer coarse alignment mark that is captured and the default wafer coarse alignment mark self stored in described error range for the position of wafer.General coarse alignment be subjected to the hardware designs searching scope restriction of camera head 3 apart from adjusting range and angle adjustment scope.
In the embodiment of the invention, coarse alignment apart from adjusting range for adjust basic point be central point-200um is to the distance range of+200um, for example the scope adjusted of distance be ± 20um, ± 40um, ± 60um, ± 80um, ± 100um, ± 120um, ± 140um, ± 160um, ± 180um, ± 200um.And the angle adjustment scope of coarse alignment for adjust basic point be central point-4mrad is to+4mrad, for example the scope of angle adjustment be ± 0.2mrad, ± 0.4mrad, ± 0.6mrad, ± 0.8mrad, ± 1mrad, ± 1.2mrad, ± 1.4mrad, ± 1.6mrad, ± 1.8mrad, ± 2mrad, ± 2.2mrad, ± 2.4mrad, ± 2.6mrad, ± 2.8mrad, ± 3mrad, ± 3.2mrad, ± 3.4mrad, ± 3.6mrad, ± 3.8mrad, ± 4mrad.If the deviation of the wafer coarse alignment mark that captures and the default wafer coarse alignment mark self stored is in described error range, then coarse alignment is finished, and wafer can be admitted in the lithographic equipment.If coarse alignment failure, at this moment can be by repeating coarse alignment once more, perhaps directly change not on the same group the mode of coarse alignment mark and come retry.
With reference to shown in Figure 7, according to through the fine alignment mark on the wafer of coarse alignment to the wafer fine alignment.After wafer was admitted to lithographic equipment, lithographic equipment also can be with mask and wafer alignment, promptly said fine alignment.Equally also has the fine alignment mark on the wafer.The fine alignment mark generally all is that some are parallel to each other, and has the grating type structure of certain intervals.For example the length of the grating of fine alignment mark is 324.2 to 726.65um, as 324.2um, 340um, 360um, 380um, 400um, 420um, 440um, 460um, 480um, 500um, 520um, 540um, 560um, 580um, 600um, 620um, 640um, 660um, 680um, 700um, 726.65um, the width of fine alignment mark is 38 or 72um, and the grating cycle of fine alignment mark is 16 or 17.6um.
Further, in order to make the better effects if of fine alignment, if the width of fine alignment mark is 38um, other graphic structures do not have in the scope of fine alignment mark periphery ± 1um, and if the width of fine alignment mark is 72um, other graphic structures do not have in the scope of fine alignment mark periphery ± 4um.As previously mentioned, fine alignment mainly contains several technology of light field, details in a play not acted out on stage, but told through dialogues and optical grating diffraction.What at present, lithographic equipment adopted mostly is that the fine alignment mode is an optical grating diffraction.Optical grating diffraction is meant that illumination beam on the grating type alignment mark diffraction takes place, and diffraction light carries the full detail about the structure of alignment mark.The multilevel diffraction light scatters from the phase alignment grating with different angles, after filtering zero order light by spatial filter, gather diffraction light ± 1 order diffraction light, the perhaps raising that requires along with characteristic size, gather multi-level diffraction light simultaneously at plane of reference interference imaging, survey and signal processing through photodetector, determine the centring position.
The embodiment of the invention can be applied to photoetching process, and with reference to shown in Figure 8, described photoetching method comprises the following steps,
Step s100 provides the surface to have the wafer of photoresist layer;
Step s200, according to the coarse alignment mark on the wafer for the wafer coarse alignment, and according to the fine alignment mark on the wafer of coarse alignment for the wafer fine alignment;
Step s300 carries out exposure imaging for the photoresist layer through the crystal column surface of coarse alignment and fine alignment and forms the photoresist layer opening;
Step s400 is a mask with the photoresist layer, carries out etching at described photoresist layer aperture position for wafer.
In conjunction with Fig. 8 and shown in Figure 9, the wafer 100 that provides the surface to have photoresist layer 101.Described photoresist layer 101 is generally photoresist or other photosensitive material layer.With the photoresist is example, and the method for conventional gluing has brush method, spin coating method and infusion method etc.Wherein, a kind of method of smearing photoresist of optimizing is dynamically to spray the gluing method, before resist coating, wafer can be attracted on the sucker and with lower rotating speed, 500rpm low speed rotation for example, afterwards, crystal column surface is constantly exported and be sprayed to photoresist by transmission pipeline.The effect of low speed rotation is to help the initial even diffusion of photoresist.After photoresist extended, sucker will drive the wafer high speed rotating and finish final photoresist expansion, thereby obtained thin and uniform photoresist film.
In conjunction with Fig. 8 and shown in Figure 10, according to the coarse alignment mark on the wafer 100 for wafer 100 coarse alignments, and according to the fine alignment mark on the wafer 100 of coarse alignment for wafer 100 fine alignments.
When carrying out coarse alignment for wafer 100, with reference to aforesaid, wafer 100 is placed on the rotary-tray, rotary-tray drives wafer 100 rotations, and camera head is opened.Store any of two kinds of above-mentioned wafer coarse alignment marks in the camera head.
When rotary-tray drove wafer 100 rotations, camera head can be caught the figure on the wafer 100, and compares with the wafer coarse alignment mark of self storing.When wafer 100 zones that comprise wafer coarse alignment mark turned to the below of camera head, camera head captured wafer coarse alignment mark, and compared with the wafer coarse alignment mark of self storing.Set the error range of coarse alignment in the embodiment of the invention.The line-spacing error range of coarse alignment be wafer coarse alignment mark that camera head the captures distance that departs from the default wafer coarse alignment mark of being stored for-1um to+1um, the distance that for example departs from the default wafer coarse alignment mark of being stored for ± 0.1um, ± 0.2um, ± 0.3um, ± 0.4um, ± 0.5um, ± 0.6um, ± 0.7um, ± 0.8um, ± 0.9um, ± 1um.The angular error scope of coarse alignment be wafer coarse alignment mark that camera head the captures angle that departs from the default wafer coarse alignment mark of being stored for-0.1mrad to+0.1mrad, for example ± 0.01mrad, ± 0.02mrad, ± 0.03mrad, ± 0.04mrad, ± 0.05mrad, ± 0.06mrad, ± 0.07mrad, ± 0.08mrad, ± 0.09mrad, ± 0.1mrad.
After camera head is with wafer coarse alignment mark that captures and the default wafer coarse alignment mark comparison of self storing, if the deviation of the wafer coarse alignment mark that captures and the wafer coarse alignment mark of self storing is above described error range, then can make adjustment deviation up to wafer coarse alignment mark that is captured and the wafer coarse alignment mark self stored in described error range for the position of wafer.General coarse alignment be subjected to the hardware designs searching scope restriction of camera head apart from adjusting range and angle adjustment scope.
In the embodiment of the invention, coarse alignment apart from adjusting range for adjust basic point be central point-200um is to the distance range of+200um, for example the scope adjusted of distance be ± 20um, ± 40um, ± 60um, ± 80um, ± 100um, ± 120um, ± 140um, ± 160um, ± 180um, ± 200um.And the angle adjustment scope of coarse alignment for adjust basic point be central point-4mrad is to+4mrad, for example the scope of angle adjustment be ± 0.2mrad, ± 0.4mrad, ± 0.6mrad, ± 0.8mrad, ± 1mrad, ± 1.2mrad, ± 1.4mrad, ± 1.6mrad, ± 1.8mrad, ± 2mrad, ± 2.2mrad, ± 2.4mrad, ± 2.6mrad, ± 2.8mrad, ± 3mrad, ± 3.2mrad, ± 3.4mrad, ± 3.6mrad, ± 3.8mrad, ± 4mrad.If the deviation of the wafer coarse alignment mark that captures and the default wafer coarse alignment mark self stored is in described error range, then coarse alignment is finished, and wafer 100 can be admitted in the lithographic equipment.If coarse alignment failure, at this moment can be by repeating coarse alignment once more, perhaps directly change not on the same group the mode of coarse alignment mark and come retry.
After wafer 100 was admitted to lithographic equipment, lithographic equipment also can be aimed at mask with wafer 100, promptly said fine alignment.Equally also has the fine alignment mark on the wafer 100.The fine alignment mark generally all is that some are parallel to each other, and has the grating type structure of certain intervals.For example the length of the grating of fine alignment mark is 324.2 to 726.65um, as 324.2um, 340um, 360um, 380um, 400um, 420um, 440um, 460um, 480um, 500um, 520um, 540um, 560um, 580um, 600um, 620um, 640um, 660um, 680um, 700um, 726.65um, the width of fine alignment mark is 38 or 72um, and the grating cycle of fine alignment mark is 16 or 17.6um.
Further, in order to make the better effects if of fine alignment, if the width of fine alignment mark is 38um, other graphic structures do not have in the scope of fine alignment mark periphery ± 1um, and if the width of fine alignment mark is 72um, other graphic structures do not have in the scope of fine alignment mark periphery ± 4um.As previously mentioned, fine alignment mainly contains several technology of light field, details in a play not acted out on stage, but told through dialogues and optical grating diffraction.What at present, lithographic equipment adopted mostly is that the fine alignment mode is an optical grating diffraction.Optical grating diffraction is meant that illumination beam on the grating type alignment mark diffraction takes place, and diffraction light carries the full detail about the structure of alignment mark.The multilevel diffraction light scatters from the phase alignment grating with different angles, after filtering zero order light by spatial filter, gather diffraction light ± 1 order diffraction light, the perhaps raising that requires along with characteristic size, gather multi-level diffraction light simultaneously at plane of reference interference imaging, survey and signal processing through photodetector, determine the centring position.
In conjunction with Fig. 8 and shown in Figure 11, carry out exposure imaging for photoresist layer 101 and form the photoresist layer opening through wafer 100 surfaces of coarse alignment and fine alignment.After finishing fine alignment, also promptly after mask 102 and wafer 100 accurately aimed at, just the transmission region that can light be seen through on the mask by the method for exposure shines on the photoresist layer 101 on wafer 100 surfaces, this regional photoresist layer is become dissolve in developer solution.At present, exposure light source commonly used has high-pressure mercury lamp, excimer laser, X ray or electron beam.
And after exposure,, soluble photoresist layer is removed formation photoresist layer opening by the method for developing in conjunction with Fig. 8 and shown in Figure 12.Described development generally all is to adopt the method for wet development that soluble photoresist layer zone is removed.Wet development generally adopts developer solution, for example TMAH (tetramethyl aqua ammonia) or Acetone (acetone), and described photoresist layer opening is exactly the size that has defined the wafer area that will remove in photoetching process in fact.
In conjunction with Fig. 8 and shown in Figure 13, be mask with photoresist layer 101, carry out etching at described photoresist layer 101 aperture positions for wafer.After the size of the opening of having determined photoresist layer 101, just can use etching method and carry out etching for wafer, thereby finally make figure transfer on the mask to wafer at photoresist layer 101 aperture positions.At present, etch process has two big classes: wet etching and dry etching.Wherein wet etching has methods such as silicon wet etching, silicon dioxide wet etching, aluminium film wet etching, deposited oxide wet etching, silicon nitride wet etching, wet spraying etching and vapor etch.And dry etching has methods such as plasma etching, ion beam milling and reactive ion etching.Described etch process is according to the difference of the material layer on the required etched wafer and difference, and etching period also is according to etched depth and applied engraving method the etch-rate of etching material to be decided.
In sum, the wafer coarse alignment mark that such scheme adopts is similar to the alignment mark structure of lithographic equipment calibration usefulness, the wafer coarse alignment mark of this structure can be marked at fine alignment and carry out exposure imaging and etching forming in the front procedure simultaneously, thereby better with the fine alignment mark coupling in the lithographic equipment, thereby the wafer coarse alignment mark of such scheme can improve lithographic equipment finds the fine alignment mark in the fine alignment process success rate.
Though oneself discloses the present invention as above with preferred embodiment, the present invention is defined in this.Any those skilled in the art without departing from the spirit and scope of the present invention, all can do various changes and modification, so protection scope of the present invention should be as the criterion with claim institute restricted portion.
Claims (25)
1. semiconductor device, comprise the central area and around the fringe region of central area, wherein said fringe region has wafer coarse alignment mark, it is characterized in that, described wafer coarse alignment mark comprises first structure and is distributed in second structure of the first structure periphery, described first structure is cross shape, and described second structure comprises four groups of gratings, and two groups of wherein adjacent gratings are orthogonal.
2. semiconductor device as claimed in claim 1 is characterized in that, described wafer coarse alignment is labeled as the grating groove.
3. semiconductor device as claimed in claim 2 is characterized in that, the degree of depth of described grating groove is 1200 to 1400 dusts.
4. semiconductor device as claimed in claim 1 is characterized in that, the width of described fringe region is 3 to 7mm.
5. semiconductor device as claimed in claim 4 is characterized in that, described wafer coarse alignment mark is positioned at and departs from the diameter wafer angular range at-20 ° to+20 ° fringe region.
6. a wafer coarse alignment mark is characterized in that, comprising: first structure and second structure that is distributed in the first structure periphery, and described first structure is cross shape, and described second structure comprises four groups of gratings, and two groups of wherein adjacent gratings are orthogonal.
7. wafer coarse alignment mark as claimed in claim 6 is characterized in that, described four groups of gratings have two kinds of different grating cycles at least.
8. wafer coarse alignment mark as claimed in claim 7 is characterized in that the described grating cycle is 16um or 17.6um.
9. wafer coarse alignment mark as claimed in claim 6 is characterized in that, described four groups of gratings be shaped as rectangle.
10. wafer coarse alignment mark as claimed in claim 9 is characterized in that, the length of grating is 168 to 200um in the described grating group.
11. wafer coarse alignment mark as claimed in claim 9 is characterized in that, the spacing of described two adjacent groups grating is 26 to 84um.
12. wafer coarse alignment mark as claimed in claim 6 is characterized in that, non-conterminous two groups of gratings are that the center is centrosymmetric with first structure in described four groups of gratings.
13. wafer coarse alignment mark as claimed in claim 6 is characterized in that described first structure is the cross hairs form.
14. wafer coarse alignment mark as claimed in claim 6 is characterized in that, described first structure cross hairs box form that the cross frame of sealing is formed of serving as reasons.
15. wafer coarse alignment mark as claimed in claim 6 is characterized in that, described first structure is four groups of paired-line cross forms that orthogonal parallel wire is formed.
16. coarse alignment method, comprise: the wafer with wafer coarse alignment mark is provided, with wafer coarse alignment mark on the wafer and default wafer coarse alignment mark comparison, adjust wafer position according to comparison result, it is characterized in that described wafer coarse alignment mark comprises, first structure and second structure that is distributed in the first structure periphery, described first structure is cross shape, and described second structure comprises four groups of optical grating constructions, and two groups of wherein adjacent gratings are orthogonal.
17. coarse alignment method as claimed in claim 16 is characterized in that, described four groups of gratings have two kinds of different grating cycles at least.
18. coarse alignment method as claimed in claim 17 is characterized in that, the described grating cycle is 16um or 17.6um.
19. coarse alignment method as claimed in claim 16 is characterized in that, described four groups of gratings be shaped as rectangle.
20. coarse alignment method as claimed in claim 19 is characterized in that, the length of grating is 168 to 200um in the described grating group.
21. coarse alignment method as claimed in claim 19 is characterized in that, the spacing of described two adjacent groups grating is 26 to 84um.
22. coarse alignment method as claimed in claim 16 is characterized in that, non-conterminous two groups of gratings are that the center is centrosymmetric with first structure in described four groups of gratings.
23. coarse alignment method as claimed in claim 16 is characterized in that, described first structure is the cross hairs form.
24. coarse alignment method as claimed in claim 16 is characterized in that, described first structure cross hairs box form that the cross frame of sealing is formed of serving as reasons.
25. coarse alignment method as claimed in claim 16 is characterized in that, described first structure is four groups of paired-line cross forms that orthogonal parallel wire is formed.
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Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102221792A (en) * | 2010-04-13 | 2011-10-19 | 中芯国际集成电路制造(上海)有限公司 | Alignment method performed in semiconductor lithography process |
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| CN114038776A (en) * | 2022-01-11 | 2022-02-11 | 广州粤芯半导体技术有限公司 | Method for solving alignment deviation caused by wafer warping deformation |
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| CN1963679A (en) * | 2006-11-24 | 2007-05-16 | 上海微电子装备有限公司 | Alignment mark structure for aligning wafer |
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| CN101900842B (en) * | 2009-05-26 | 2014-08-20 | 鸿富锦精密工业（深圳）有限公司 | Mold core and manufacturing method of micro-optical lens array |
| CN102221792A (en) * | 2010-04-13 | 2011-10-19 | 中芯国际集成电路制造(上海)有限公司 | Alignment method performed in semiconductor lithography process |
| CN102385263A (en) * | 2010-08-25 | 2012-03-21 | 中芯国际集成电路制造(上海)有限公司 | Method for aligning previous-layer graphs and photomask applicable to method |
| CN102385263B (en) * | 2010-08-25 | 2014-10-01 | 中芯国际集成电路制造(上海)有限公司 | Method for aligning previous-layer graphs and photomask applicable to method |
| CN102683253A (en) * | 2012-05-04 | 2012-09-19 | 上海华力微电子有限公司 | Method for improving line width measurement accuracy alignment of picture |
| CN102683253B (en) * | 2012-05-04 | 2015-07-22 | 上海华力微电子有限公司 | Method for improving line width measurement accuracy alignment of picture |
| CN104460246A (en) * | 2013-09-12 | 2015-03-25 | 上海微电子装备有限公司 | Novel lithography alignment method |
| US9791790B2 (en) | 2013-10-16 | 2017-10-17 | Institute Of Semiconductors, Chinese Academy Of Sciences | Method of aligning quadrate wafer in first photolithography process |
| WO2015054977A1 (en) * | 2013-10-16 | 2015-04-23 | 中国科学院半导体研究所 | Method for aligning square wafer in first photolithographic process |
| CN105573049A (en) * | 2014-11-07 | 2016-05-11 | 西南科技大学 | Proximity nano-lithography double grating automatic alignment marks |
| CN105467747A (en) * | 2016-01-09 | 2016-04-06 | 北京工业大学 | Alignment mark and mask |
| CN105737879A (en) * | 2016-03-01 | 2016-07-06 | 中国电子科技集团公司第十三研究所 | Micron grade raster calibration sample wafer with step height |
| CN109860153A (en) * | 2019-03-29 | 2019-06-07 | 长江存储科技有限责任公司 | Integrated circuit device, the method and photomask for forming alignment measurement pattern |
| CN111693003A (en) * | 2020-06-19 | 2020-09-22 | 西安微电子技术研究所 | Wafer-level nanoscale measurement standard device and manufacturing method thereof |
| CN112882340A (en) * | 2021-04-29 | 2021-06-01 | 中芯集成电路制造(绍兴)有限公司 | Photomask, monitoring wafer and method for monitoring wafer surface cleaning precision |
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| CN114038776A (en) * | 2022-01-11 | 2022-02-11 | 广州粤芯半导体技术有限公司 | Method for solving alignment deviation caused by wafer warping deformation |
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