CN102200428A - High-precision vertical position measurement device - Google Patents

High-precision vertical position measurement device Download PDF

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Publication number
CN102200428A
CN102200428A CN 201010130820 CN201010130820A CN102200428A CN 102200428 A CN102200428 A CN 102200428A CN 201010130820 CN201010130820 CN 201010130820 CN 201010130820 A CN201010130820 A CN 201010130820A CN 102200428 A CN102200428 A CN 102200428A
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China
Prior art keywords
chopper
measuring beam
silicon chip
quadrants
quadrant
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Pending
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CN 201010130820
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Chinese (zh)
Inventor
金小兵
李志丹
陈飞彪
鲁武旺
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Shanghai Micro Electronics Equipment Co Ltd
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Shanghai Micro Electronics Equipment Co Ltd
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Priority to CN 201010130820 priority Critical patent/CN102200428A/en
Publication of CN102200428A publication Critical patent/CN102200428A/en
Pending legal-status Critical Current

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Abstract

The invention relates to a high-precision vertical position measurement device. When the device is used, the measurement light beam emitted from the light source is reflected by the to-be-measured silicon wafer and then enters into a highly rotary chopper; the chopper converts the measurement light beam into high frequency optical signals which are received by a two-quadrant PD; the two-quadrant PD converts the high frequency optical signals into electrical signals in two quadrants, and the vertical shifting information of the measured silicon wafer can be known by analyzing the electrical signals in two quadrants.

Description

High precision vertical position measurement mechanism
Technical field
The present invention relates to a kind of lithographic equipment, relate in particular to the silicon chip vertical position measurement mechanism in the lithographic equipment.
Background technology
In today of scientific and technological develop rapidly, photoelectric measurement is more and more higher at the shared proportion of high-tech area, eliminates the most effective means of external interference often and optical signalling is carried out high frequency modulated.Patent U.S.Patent:5461237 has proposed a kind of vertical measuring method, its signal modulation is to utilize the scanning reflection mirror of dither to produce the high frequency optical detection signal, but the signal modulating frequency depends on the vibration frequency of surface sweeping catoptron fully in this method, the frequency adjustment is quite difficult, adjusting range is also very limited, and the scanning reflection mirror of dither will bring harsh noise.Design one cover can be modulated in the certain frequency scope optical signalling, and does not bring the vertical measuring method of high frequency noise to seem more and more important.
Summary of the invention
The object of the present invention is to provide a kind of vertical position measurement mechanism, this device can be modulated in the certain frequency scope the measuring light signal, and can not bring high frequency noise.
The invention provides a kind of high precision vertical position measurement mechanism, in this device, after reflecting via tested silicon chip, the measuring beam that light source sends is incident to the chopper of high speed rotating, chopper converts measuring beam to the high frequency optical signalling, this high frequency optical signalling is received by two quadrant PD, two quadrant PD becomes the electric signal of two quadrants with high frequency optics conversion of signals, the electric signal of two quadrants is carried out analyzing and processing draw tested silicon chip in vertical offset information.
Wherein, before being incident to tested silicon chip surface, adjust the size of measuring beam by projection slit.
Wherein, utilize collimation lens that the measuring beam that light source sends is converted to directional light, be incident to projection slit then.
Wherein, utilize first catoptron that the measuring beam of projection slit outgoing is reflexed on the tested silicon chip surface.
Wherein, utilize second catoptron that the measuring beam of tested silicon chip surface reflection is reflexed to the dull and stereotyped adjusting mechanism of biasing, to change the offset direction and the side-play amount of light beam.
Wherein, reflex to chopper by will the setover measuring beam of dull and stereotyped adjusting mechanism outgoing of the 3rd catoptron.
Wherein, being incident to the measuring beam of chopper can be fully by the light hole on the chopper.
Wherein, the geomery of light hole is greater than the geomery of the hot spot of the measuring beam of incident.
Wherein, when the upper surface of tested silicon chip is positioned at the optimal focal plane place, the energy summation maximum that two quadrants of two quadrant PD record, and the difference of the energy of two quadrants is zero.
Wherein, judge the vertical position side-play amount and the offset direction of tested silicon chip upper surface according to the difference of the energy of two quadrants.
Wherein, change the modulating frequency of this device by adjusting light hole along the quantity of chopper radial position, increase and decrease light hole, the means such as rotational speed of switching chopper.
The moving component of this device has only the chopper of a high speed rotating, simple in structure, be easy to realize, the signal frequency modulation range is bigger, dirigibility is good, applicability is strong, and the quantity of square opening, adjustment square hole all can change the modulating frequency of this device on the increase and decrease chopper along the rotational speed of chopper radial position or switching chopper.With respect to the modulating apparatus of dither, this vertical position measurement mechanism adopts the chopper of high speed rotating that signal is modulated can reduce noise effectively.
Description of drawings
Figure 1 shows that the vertical position measurement mechanism structural representation that is used for litho machine according to of the present invention.
Figure 2 shows that the modulating apparatus structural representation.
Figure 3 shows that the measurement hot spot synoptic diagram that two quadrant PD receives.
Figure 4 shows that the measurement hot spot synoptic diagram that two quadrant PD received when measured of vertical position measurement mechanism with respect to the projection objective optimal focal plane skew took place.
Figure 5 shows that the light intensity energy trace synoptic diagram that two quadrant PD receives.
Fig. 6 is the treatment scheme synoptic diagram of measuring-signal.
Embodiment
Below, describe in detail according to a preferred embodiment of the invention in conjunction with the accompanying drawings.
High precision of the present invention vertical position measurement mechanism, the silicon chip vertical position that can be used in the litho machine is measured, as shown in Figure 1.The parasitic light that vertical position measurement mechanism light source 2 sends forms the horizontal survey light beam through collimation lens 3 backs, parallel beam sees through projection slit 4 backs and guides light beam into tested silicon chip 6 upper surfaces by catoptron 5, silicon chip 6 is fixed on the worktable 7, can move with worktable 7.Measuring beam is after silicon chip 6 reflections, carrying the silicon chip surface positional information and seeing through the dull and stereotyped adjusting mechanism 9 of biasing by catoptron 8 reflection backs, last toward mirror 10, the chopper 11 of high speed rotating guided light beam into by catoptron 10, the light beam that sees through the chopper square hole is received by two quadrant PD12, carry out analyzing and processing by the light intensity energy that two quadrant PD12 is received, obtain the vertical position information of measured silicon chip 6 with respect to projection objective 1 optimal focal plane.
The dull and stereotyped adjusting mechanism 9 of biasing in the measurement mechanism of litho machine vertical position can be used for changing the offset direction of measuring beam, before the operate as normal, at first adjust this mechanism, make when measured silicon chip 6 upper surfaces overlap with the focal plane of projection objective 1, through the measuring beam after catoptron 10 reflection can be all through the square hole 102 of chopper, as shown in Figure 2.On two quadrant PD12, form a measurement hot spot 203 and see through the light beam of square hole this moment, as shown in Figure 3.Adjust the installation site of two quadrant PD12, make hot spot 203 identical with spot size on second quadrant 202 at first quartile on the dual-quadrant detector 201, promptly when measured silicon chip 6 is in projection objective 1 optimal focal plane position, it is identical that two quadrant PD12 goes up the light intensity energy that receives on first quartile 201 and second quadrant 202.
For the ease of measuring, vertical position measurement mechanism projection slit 4 and light path layout relation must satisfy following condition, and the measuring light spot size after reflecting through catoptron 10 is less than the square hole size on the chopper 11.During operate as normal, chopper 11 high speed rotating, what this moment, two quadrant PD12 received is a high-frequency signal.Suppose that carving the light intensity energy that first quartile 201 receives on the two quadrant PD12 at a time is E 1, the light intensity energy that second quadrant 202 receives is E 2, as shown in Figure 3, when measured silicon chip 6 upper surfaces were in projection objective 1 optimal focal plane position, the energy that receives on last two quadrants 201 of two quadrant PD12 and 202 was identical, i.e. E 1=E 2When measured silicon chip 6 upper surfaces with respect to the projection objective optimal focal plane skew took place, as shown in Figure 4, the energy that receives on last two quadrants 201 of two quadrant PD12 and 202 was inequality, if forward migration, E shown in 301 take place 1>E 2, if negative offset, E shown in 302 take place 1<E 2
If the energy summation of two quadrants of two quadrant PD is E, i.e. E=E 1+ E 2, the difference of energy is Δ E, i.e. Δ E=E 1-E 2, as shown in Figure 5, dotted line is represented energy summation E among the figure, solid line is represented the difference Δ E of energy.At t 0, t 1, t 2When measuring beam is fully through the square hole on the chopper constantly, the light intensity energy summation E maximum that two quadrant PD receives, this moment, Δ E reflected measured side-play amount.When measured face is in the optimal focal plane position, Δ E=0 shown in 401, when measured during with respect to optimal focal plane generation forward migration, Δ E>0 shown in 402, when measured during with respect to optimal focal plane generation negative offset, Δ E<0 shown in 403.Therefore, obtain the peaked moment at E, the size of Δ E has reflected the size of measured side-play amount, simultaneously the positive and negative direction that also reflects skew of Δ E.
Whole signal processing as shown in Figure 6, at first respectively the output signal of two quadrants of two quadrant PD12 is gathered, respectively the two-way measuring-signal is carried out which amplitude modulation with square wave then, after finishing, modulation carries out analog filtering and A/D conversion again, two ways of digital signals after the A/D conversion is subtracted each other, interpretation of result is calculated to draw vertical measured value at last.
Described in this instructions is several preferred embodiment of the present invention, and above embodiment is only in order to illustrate technical scheme of the present invention but not limitation of the present invention.All those skilled in the art all should be within the scope of the present invention under this invention's idea by the available technical scheme of logical analysis, reasoning, or a limited experiment.

Claims (11)

1. high precision vertical position measurement mechanism, in this device, after reflecting via tested silicon chip, the measuring beam that light source sends is incident to the chopper of high speed rotating, chopper converts measuring beam to the high frequency optical signalling, this high frequency optical signalling is received by two quadrant PD, two quadrant PD becomes the electric signal of two quadrants with high frequency optics conversion of signals, the electric signal of two quadrants is carried out analyzing and processing draw tested silicon chip in vertical offset information.
2. device according to claim 1 is characterized in that, before being incident to tested silicon chip surface, adjusts the size of measuring beam by projection slit.
3. device according to claim 2 is characterized in that, utilizes collimation lens that the measuring beam that light source sends is converted to directional light, is incident to projection slit then.
4. device according to claim 3 is characterized in that, utilizes first catoptron that the measuring beam of projection slit outgoing is reflexed on the tested silicon chip surface.
5. device according to claim 4 is characterized in that, utilizes second catoptron that the measuring beam of tested silicon chip surface reflection is reflexed to the dull and stereotyped adjusting mechanism of biasing, to change the offset direction and the side-play amount of light beam.
6. device according to claim 5 is characterized in that, reflexes to chopper by will the setover measuring beam of dull and stereotyped adjusting mechanism outgoing of the 3rd catoptron.
7. device according to claim 6 is characterized in that, the measuring beam that is incident to chopper can be fully by the light hole on the chopper.
8. device according to claim 7 is characterized in that the geomery of light hole is greater than the geomery of the hot spot of the measuring beam of incident.
9. device according to claim 7 is characterized in that, when the upper surface of tested silicon chip is positioned at the optimal focal plane place, and the energy summation maximum that two quadrants of two quadrant PD record, and the difference of the energy of two quadrants is zero.
10. device according to claim 9 is characterized in that, judges the vertical position side-play amount and the offset direction of tested silicon chip upper surface according to the difference of the energy of two quadrants.
11. according to any one described device in the claim 1~10, it is characterized in that, change the modulating frequency of this device along the quantity of chopper radial position, increase and decrease light hole, the means such as rotational speed of switching chopper by adjusting light hole.
CN 201010130820 2010-03-23 2010-03-23 High-precision vertical position measurement device Pending CN102200428A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103389623A (en) * 2012-05-11 2013-11-13 上海微电子装备有限公司 Focusing and leveling device
CN104390605A (en) * 2014-12-01 2015-03-04 中国科学院微电子研究所 Vertical adjustment device

Citations (7)

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Publication number Priority date Publication date Assignee Title
JPH11230740A (en) * 1998-02-12 1999-08-27 Topcon Corp Distance measurement device
DE10115264A1 (en) * 2000-09-08 2002-04-04 Mitsubishi Material Silicon Silicon wafer quality evaluation involves computing signal data for photoluminescence light intensities, from preset formulae corresponding to calculated spreading/diffusion distribution of light on thin-film layer of wafer
CN101113887A (en) * 2006-07-24 2008-01-30 吴宝同 Surface plasma resonance measurement mechanism and method thereof
CN101344734A (en) * 2007-12-28 2009-01-14 上海微电子装备有限公司 Silicon slice focusing and leveling measurement device
CN101477319A (en) * 2009-01-22 2009-07-08 上海微电子装备有限公司 Optical system used for focusing and leveling
US20090214760A1 (en) * 2005-02-26 2009-08-27 Leybold Optics Gmbh Optical Monitoring System for Coating Processes
CN101526746A (en) * 2009-01-07 2009-09-09 上海微电子装备有限公司 Vertical measuring system capable of adjusting zero-plane position

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11230740A (en) * 1998-02-12 1999-08-27 Topcon Corp Distance measurement device
DE10115264A1 (en) * 2000-09-08 2002-04-04 Mitsubishi Material Silicon Silicon wafer quality evaluation involves computing signal data for photoluminescence light intensities, from preset formulae corresponding to calculated spreading/diffusion distribution of light on thin-film layer of wafer
US20090214760A1 (en) * 2005-02-26 2009-08-27 Leybold Optics Gmbh Optical Monitoring System for Coating Processes
CN101113887A (en) * 2006-07-24 2008-01-30 吴宝同 Surface plasma resonance measurement mechanism and method thereof
CN101344734A (en) * 2007-12-28 2009-01-14 上海微电子装备有限公司 Silicon slice focusing and leveling measurement device
CN101526746A (en) * 2009-01-07 2009-09-09 上海微电子装备有限公司 Vertical measuring system capable of adjusting zero-plane position
CN101477319A (en) * 2009-01-22 2009-07-08 上海微电子装备有限公司 Optical system used for focusing and leveling

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103389623A (en) * 2012-05-11 2013-11-13 上海微电子装备有限公司 Focusing and leveling device
CN103389623B (en) * 2012-05-11 2015-03-25 上海微电子装备有限公司 Focusing and leveling device
CN104390605A (en) * 2014-12-01 2015-03-04 中国科学院微电子研究所 Vertical adjustment device
CN104390605B (en) * 2014-12-01 2017-05-31 北京科益虹源光电技术有限公司 A kind of vertical adjusting apparatus

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Application publication date: 20110928