CN103838088A - Focusing and levelling device and method - Google Patents
Focusing and levelling device and method Download PDFInfo
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- CN103838088A CN103838088A CN201210485158.3A CN201210485158A CN103838088A CN 103838088 A CN103838088 A CN 103838088A CN 201210485158 A CN201210485158 A CN 201210485158A CN 103838088 A CN103838088 A CN 103838088A
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- leveling device
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Abstract
The invention provides a focusing and levelling device and method. A spatial light modulator is adopted to ensure that a measurement light spot can be modulated according to the thickness of a substrate, the size of the measurement light spot is changed, and the phenomenon of ghosting of the detection light spot is prevented from generating, thus the detection precision is improved, and further the focusing and levelling device has high adaptability to the substrate; the focusing and levelling device is flexible in modulation and convenient and reliable.
Description
Technical field
The present invention relates to integrated circuit and manufacture the equipment in field, a kind of particularly focusing leveling device and focusing and leveling method being applied in projection lithography technology.
Background technology
In current projection lithography system, due to thickness deviation, the fluctuating of face shape and the projection objective of substrate, the uncertainty of focal plane position, can cause substrate to produce out of focus or inclination with respect to focal plane of lens, this will affect quality and the yield rate of integrated circuit, therefore, generally include the focusing and leveling system in order to accurate detection testee surface location and degree of tilt, make in exposure process, substrate is in position preferably.
Obviously, contactless focusing leveling device is first-selected, and conventional contactless focusing leveling device has condenser type, vapour-pressure type and optical profile type at present, optical profile type focusing leveling device with its preferably precision obtained approval in the industry.
Please refer to Fig. 1, Fig. 1 is optical profile type focusing and leveling systematic schematic diagram, its optical path is distributed in the both sides of the optical axis a-b of projection objective 13, comprise, light source 1, described light source 1 sends measures hot spot through illuminated mirror group 2, projection slit 3, group lens combination 4 before projection, after the first catoptron group 5 and projection, organize lens combination 6 and in the surperficial current exposure area of substrate 7, form measurement hot spot, after substrate 7 reflections, organize lens combination 8 through before imaging successively, after the second catoptron group 9 and imaging, organize after lens combination 10, the picture of measuring hot spot is a rectangular detection hot spot, described detection hot spot is detected device 11 and receives, and calculate pattern skew adapting to by substrate 7 etc. through arithmetic element 12.
U.S. Pat 5834767 discloses a kind of focusing leveling device, include a light source, one has the emit beam projection diaphragm of function of the light source of collection, one has the detection diaphragm of ray-collecting function, one for being along inclined direction imaged on diaphragm pattern the first optical system of body surface, one for being imaged on the picture of body surface the second optical system of surveying on diaphragm, and form Moire fringe on detection diaphragm, separately there is a photodetector, in order to survey the position of the converging ray convergent point being produced by Moire fringe, and obtain the positional information of associated body surface according to the positional information of gained convergent point.
The weak point of above-mentioned patent is, if the glass substrate that substrate is different-thickness, on photodetector, may detect two pictures that light beam become respectively through glass substrate upper surface and lower surface, i.e. 0 light (light of upper surface of base plate reflection) imaging and 1 light (light of base lower surface reflection) imaging, produce the phenomenon of hot spot ghost image, affect the glass baseplate surface shape characteristic that detector detects, cause measuring accuracy can not guarantee.
In order to solve this defect, conventionally by using the projection diaphragm of different size, thereby reduce to survey the size of hot spot, to tackle the measurement of the glass substrate that mates different-thickness.But this method can not thoroughly address the above problem.
Summary of the invention
The object of the present invention is to provide a kind of focusing leveling device and focusing and leveling method, avoid producing the phenomenon of surveying hot spot ghost image.
For solving the problems of the technologies described above, the invention provides a kind of focusing leveling device, comprise lighting unit, projecting cell, image-generating unit and probe unit, it is characterized in that, described projecting cell comprises spatial light modulator; Wherein, the measurement hot spot of described lighting unit incides projecting cell, and through spatial light modulator modulation, outgoing, to substrate, enters described probe unit through described image-generating unit again after described substrate reflection.
Optionally, for described focusing leveling device, described lighting unit comprises light source, illuminated mirror group and optical fiber, and described light source sends light after illuminated mirror group optically focused, forms measurement hot spot send by optical fiber.
Optionally, for described focusing leveling device, described projecting cell is organized lens combination after also comprising control device, the front group of projection lens combination, the first catoptron group and projection, and described control device drives described spatial light modulator modulation to measure hot spot.
Optionally, for described focusing leveling device, described image-generating unit is organized lens combination after comprising the front group of imaging lens combination, the second catoptron group and imaging, described measurement hot spot is organized lens combination successively after substrate reflection after organizing lens combination, the second catoptron group and imaging before described imaging, forms and surveys hot spot.
Optionally, for described focusing leveling device, described probe unit comprises detector and arithmetic element, and described detector receives described detection hot spot, forms light intensity signal, and described arithmetic element is calculated the pattern of described substrate according to described light intensity signal.
Optionally, for described focusing leveling device, whether described detector also transmission of signal, to described control device, is controlled described control device and is driven described spatial light modulator modulation to measure hot spot.
Optionally, for described focusing leveling device, described substrate is glass substrate.
The invention provides a kind of method that adopts focusing leveling device as above to carry out focusing and leveling, comprise the following steps,
Substrate is provided,
Described lighting unit sends measurement hot spot and is detected unit reception through described projecting cell, substrate and image-generating unit formation detection hot spot successively, if judged and had ghost image by described detector, described spatial light modulator modulation measurement hot spot, until ghost image disappearance.
Optionally, for the method for described focusing and leveling, described spatial light modulator is measured hot spot according to the size modulations of the thickness of substrate, shadow surface.
Optionally, for the method for described focusing and leveling, after described spatial light modulator modulation, the size Lp of described measurement hot spot is less than or equal to the one 0 light and the one 1 the distance L w of light on substrate, and ghost image disappears;
Described
wherein, the thickness that d is described substrate, α measures the incident angle of hot spot on substrate, the relative index of refraction that n is substrate.
Optionally, for the method for described focusing and leveling, the scope of the thickness d of described substrate is 0.2mm ~ 2mm.
Compared with prior art, in focusing leveling device provided by the invention and focusing and leveling method, adopt spatial light modulator, make it modulate measurement hot spot according to the thickness of substrate etc., change the size of measuring hot spot, avoid producing the phenomenon of surveying hot spot ghost image, thereby improve detection accuracy, and then substrate is had to stronger adaptability, and modulation is flexibly, and convenient and reliable.
Accompanying drawing explanation
Fig. 1 is the optical profile type focusing leveling device schematic diagram of prior art;
Fig. 2 is the structural representation of the focusing leveling device of one embodiment of the invention;
Fig. 3 is that the measurement hot spot of one embodiment of the invention is at the distribution schematic diagram after substrate;
Fig. 4 is the function relation figure of the thickness of distance on substrate of the one 0 light of one embodiment of the invention and the one 1 light and substrate;
Fig. 5 is that one embodiment of the invention solves the schematic diagram of surveying hot spot ghost image;
Fig. 6 is the curve map that the focusing leveling device of prior art is measured 6 kinds of substrates;
Fig. 7 adopts the focusing leveling device of one embodiment of the invention to 6 kinds of identical curve maps that substrate is measured.
Embodiment
Below in conjunction with the drawings and specific embodiments, focusing leveling device provided by the invention and method are described in further detail.According to the following describes and claims, advantages and features of the invention will be clearer.It should be noted that, accompanying drawing all adopts very the form of simplifying, only in order to convenient, the object of the aid illustration embodiment of the present invention lucidly.
The invention provides a kind of focusing leveling device, please refer to Fig. 2, comprising:
By the lighting unit that comprises that light source 101, illuminated mirror group 102 and optical fiber form, described light source 101 sends light after illuminated mirror group 102 optically focused, forms measurement hot spot and sends, for measuring use by optical fiber;
Projecting cell, described projecting cell is organized lens combination 106 after comprising spatial light modulator 103a, control device 103b, the front group of projection lens combination 104, the first catoptron group 105 and projection, described control device 103b produces control signal and drives described spatial light modulator 103a, make to measure hot spot and send with the need corresponding variation, to adapt to measure needs; Described measurement hot spot is organized lens combination 106 successively and is reached on substrate 107 after organizing lens combination 104, the first catoptron group 105 and projection before described spatial light modulator 103a, projection, concrete, described substrate 107 is positioned on plummer 114, measure substrate 107 surfaces described in hot spot incident current exposure area (be projection objective 113 optical axis A-A under) form and measure hot spot, after substrate 107 reflections, also pass through:
Image-generating unit, described image-generating unit comprises multiple catoptrons, concrete, comprise: according to measuring hot spot direction of transfer, after being arranged in order the front group of imaging lens combination 108, the second catoptron group 109 and imaging, organize lens combination 110, arrive afterwards the detector 111 of probe unit, form and survey hot spot, described detector 111 changes detection hot spot into light intensity signal (as periodically variable light intensity signal) and is received by arithmetic element 112, thereby calculated the pattern of substrate 107 by described light intensity signal, skew etc.Whether meanwhile, described detector is extremely described control device 103b of transmission of signal also, control described control device 103b and drive spatial light modulator 103a modulation to measure hot spot.
At this, described substrate 107 can be glass substrate, can preferably show advantage of the present invention.
Provide a kind of focusing leveling device as above to carry out the method for focusing and leveling below, comprising:
Substrate is provided,
Lighting unit sends measurement hot spot and is detected unit reception through described projecting cell, substrate and image-generating unit formation detection hot spot successively, if there is ghost image (measuring hot spot ghost image) by detector judgement, hot spot is measured in spatial light modulator modulation, until ghost image disappears.Wherein, described spatial light modulator is measured hot spot according to the size modulations of the thickness of substrate, shadow surface (measuring hot spot).
Make a concrete analysis of as follows: substrate has thickness d, be incident on substrate with α angle after a series of optical device when measuring hot spot, in the time being glass substrate, being easy to change and having 0 light and 1 light generation, please refer to Fig. 3, the spacing between the 31 and the 1 light 33 of described the one 0 light is L
p ⊥, obvious, occur for fear of surveying hot spot ghost image, survey the effective dimensions L of hot spot
⊥(shape of described detection hot spot is not limit, and should be understood to produce in this effective dimensions length or the maximum length that the direction of ghost image has, and shows the distance between the 31 and the 20 light 32 of the one 0 light in Fig. 3) should be less than L
p ⊥, should there is the length L p that measures hot spot to be less than or equal to the 31 and the 1 the distance L w of light 33 on substrate 107 of the one 0 light, described in
wherein, the thickness that d is substrate, α measures the incident angle of hot spot on substrate, the relative index of refraction that n is substrate.
Fig. 4 has provided the function relation figure of Lp and d, in the present embodiment, adopt the glass substrate that relative index of refraction n is 1.5, incident angle α is 75 °, can be regarded as to obtain Lw=1.6834d,, in the time of Lp≤1.6834d, survey hot spot without ghost image, conventionally can adopt thickness is the glass substrate of 0.2mm ~ 2mm, and the length L p that measures hot spot is generally greater than 10um.
Below in conjunction with Fig. 5, focusing and leveling method of the present invention is elaborated: known in the time of situation 51, the thickness that is substrate 107 is d1, survey hot spot and there is no ghost image (having omitted the process of light path through image-generating unit in Fig. 5), in the time not modulating focusing leveling device, using thickness instead is d2(d2<d1) substrate, occur as shown in situation 52, when exposing to, measurement hot spot has on the substrate 107 that thickness is d2, measure the length L p=Lp1 of hot spot, and the 31 and the 1 the distance L w=Lw1 of light 32 on substrate 107 of the one 0 light, now Lp>Lw, the detection hot spot on detector 111 has ghost image.Now spatial light modulator is measured hot spot in the control modulated of control device, until obtain as shown in situation 53, make to measure the length L p=Lp2 that measures hot spot when hot spot exposes to substrate 107, meet Lp2<Lp1, and Lp2≤Lw1, there is not ghost image in the detection hot spot receiving on detector 111.Just reached in the thickness substrate surface shape characteristic of different-thickness and the measurement object of position, improved detection accuracy.
Meanwhile, the present invention has chosen 6 kinds of different substrates targetedly, adopts respectively the focusing leveling device of available technology adopting projection diaphragm and focusing leveling device of the present invention to measure.Please refer to Fig. 6 and Fig. 7, can find out by Fig. 6, to SiN
2having there is detection hot spot ghost phenomena in measuring in substrate and glass substrate, uses focusing leveling device of the present invention to obtain the result shown in Fig. 7: hot spot ghost phenomena all does not appear surveying in various substrates.As can be seen here, the present invention has better reliability, can improve greatly measuring accuracy.
In focusing leveling device provided by the invention and focusing and leveling method, adopt spatial light modulator, make it modulate measurement hot spot according to the thickness of substrate etc., change the size of measuring hot spot, avoid producing the phenomenon of surveying hot spot ghost image, thereby improved detection accuracy, and then substrate is had to stronger adaptability, and modulation flexibly, convenient and reliable.
Obviously, those skilled in the art can carry out various changes and modification and not depart from the spirit and scope of the present invention invention.Like this, if within of the present invention these are revised and modification belongs to the scope of the claims in the present invention and equivalent technologies thereof, the present invention is also intended to including these changes and modification.
Claims (11)
1. a focusing leveling device, comprises lighting unit, projecting cell, image-generating unit and probe unit, it is characterized in that, described projecting cell comprises spatial light modulator; Wherein, the measurement hot spot of described lighting unit incides projecting cell, and through spatial light modulator modulation, outgoing, to substrate, enters described probe unit through described image-generating unit again after described substrate reflection.
2. focusing leveling device as claimed in claim 1, is characterized in that, described lighting unit comprises light source, illuminated mirror group and optical fiber, and described light source sends light after illuminated mirror group optically focused, forms measurement hot spot send by optical fiber.
3. focusing leveling device as claimed in claim 1, it is characterized in that, described projecting cell is organized lens combination after also comprising control device, the front group of projection lens combination, the first catoptron group and projection, and wherein said control device drives described spatial light modulator modulation to measure hot spot.
4. focusing leveling device as claimed in claim 1, it is characterized in that, described image-generating unit is organized lens combination after comprising the front group of imaging lens combination, the second catoptron group and imaging, described measurement hot spot is organized lens combination successively after substrate reflection after organizing lens combination, the second catoptron group and imaging before described imaging, forms and surveys hot spot.
5. focusing leveling device as claimed in claim 4, is characterized in that, described probe unit comprises detector and arithmetic element, and described detector receives described detection hot spot, forms light intensity signal; Described arithmetic element is calculated the pattern of described substrate according to described light intensity signal.
6. focusing leveling device as claimed in claim 5, is characterized in that, whether described detector transmission of signal, to described control device, is controlled described control device and driven described spatial light modulator modulation to measure hot spot.
7. focusing leveling device as claimed in claim 1, is characterized in that, described substrate is glass substrate.
8. the focusing leveling device of employing as described in any one in claim 1 ~ 7 carries out a method for focusing and leveling, it is characterized in that, comprises the following steps:
Substrate is provided,
Described lighting unit sends measurement hot spot and is detected unit reception through described projecting cell, substrate and image-generating unit formation detection hot spot successively, has ghost image if described detector judges, described spatial light modulator modulation measurement hot spot, until ghost image disappearance.
9. the method for focusing and leveling as claimed in claim 8, is characterized in that, described spatial light modulator is measured hot spot according to the size modulations of the thickness of substrate, shadow surface.
10. the method for focusing and leveling as claimed in claim 9, is characterized in that, after the modulation of described spatial light modulator, the length L p of described measurement hot spot is less than or equal to 0 light and 1 light distance L w on substrate, and ghost image disappears;
Described
wherein, the thickness that d is described substrate, α measures the incident angle of hot spot on substrate, the relative index of refraction that n is substrate.
The method of 11. focusing and levelings as claimed in claim 10, is characterized in that, the scope of the thickness d of described substrate is 0.2mm ~ 2mm.
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| CN106292197A (en) * | 2015-05-24 | 2017-01-04 | 上海微电子装备有限公司 | A kind of focusing leveling device based on image processing techniques and method |
| CN106933071A (en) * | 2015-12-30 | 2017-07-07 | 上海微电子装备有限公司 | Focusing leveling device and method |
| CN106933044A (en) * | 2015-12-30 | 2017-07-07 | 上海微电子装备有限公司 | The defocus slope compensating device and method of focusing and leveling |
| CN109443210A (en) * | 2018-12-13 | 2019-03-08 | 苏州亿拓光电科技有限公司 | Optical position detection device and method |
| CN112731773A (en) * | 2020-12-31 | 2021-04-30 | 中国科学院微电子研究所 | Electron beam exposure machine, focusing method and device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106292197A (en) * | 2015-05-24 | 2017-01-04 | 上海微电子装备有限公司 | A kind of focusing leveling device based on image processing techniques and method |
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| CN112731773A (en) * | 2020-12-31 | 2021-04-30 | 中国科学院微电子研究所 | Electron beam exposure machine, focusing method and device |
| CN112731773B (en) * | 2020-12-31 | 2024-04-16 | 中国科学院微电子研究所 | Electron beam exposure machine, focusing method and device |
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