CN101866111A - Method for monitoring exposure machine focal plane change - Google Patents
Method for monitoring exposure machine focal plane change Download PDFInfo
- Publication number
- CN101866111A CN101866111A CN200910082351A CN200910082351A CN101866111A CN 101866111 A CN101866111 A CN 101866111A CN 200910082351 A CN200910082351 A CN 200910082351A CN 200910082351 A CN200910082351 A CN 200910082351A CN 101866111 A CN101866111 A CN 101866111A
- Authority
- CN
- China
- Prior art keywords
- focal length
- side wall
- wall angle
- value
- focal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 34
- 238000012544 monitoring process Methods 0.000 title claims abstract description 21
- 230000008859 change Effects 0.000 title abstract description 12
- 230000008569 process Effects 0.000 claims abstract description 11
- 238000005259 measurement Methods 0.000 claims description 13
- 238000001228 spectrum Methods 0.000 claims description 11
- 230000003287 optical effect Effects 0.000 claims description 9
- 239000010408 film Substances 0.000 description 17
- 238000005516 engineering process Methods 0.000 description 8
- 239000013078 crystal Substances 0.000 description 4
- 238000012937 correction Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 241000931526 Acer campestre Species 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000001459 lithography Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000001259 photo etching Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000000985 reflectance spectrum Methods 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 238000000391 spectroscopic ellipsometry Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Images
Landscapes
- Testing Or Measuring Of Semiconductors Or The Like (AREA)
Abstract
The invention discloses a method for monitoring exposure machine focal plane change. The key points include that correspondence of side wall angle SWA and focal length is set and the correspondence curve is fitted. The method also includes that the side wall angle is monitored in exposure process of the exposure machine, focal length value corresponding to the side wall angle is determined from the fitted curve, and whether the focal plane is changed is determined. By adopting the method, exposure machine focal plane change situation can be rapidly and accurately acquired.
Description
Technical field
The present invention relates to the technical field of lithography that semiconductor is made, the method that particularly a kind of monitoring exposure machine focal plane changes.
Background technology
In the manufacture of semiconductor technology, photoetching technique is along with the improve of critical size technology, and it is more and more important to become.
The degree of stability of exposure bench is subjected to the influence of a lot of aspects, influence as aspects such as the variation of the degree of planarization of the skew of crystal wafer platform on the exposure bench or lens, crystal column surface, optical maser wavelength and environment, the capital causes the focal plane (focal length) of exposure bench to change, the true focal length value that is exposure bench is different with initial setting value, can make the size of wafer of exposure different with preset value with profile like this.
In order in time correction to be made in the variation of exposure machine focal plane, then need the variation of monitoring exposure machine focal plane.
In the prior art, at preparation focus-exposure matrix wafer (Focus Energy Matrix Wafer) afterwards, adopt critical dimension-scanning electron microscope (Critical Demension-Scanning Electron Microscope, CD-SEM), measure the two-dimentional critical size (CD) of crystal column surface, obtain under different exposure energy points, variation relation curve between CD and the focal length value, be Bai Sang curve (Bossung Curve), from Bossung Curve, obtain the optimum focusing value, this time of 1 to 2 hour of process need.Be the variation of monitoring exposure machine focal plane, then need at regular intervals, obtain a pinpointed focus value according to said method, if the focal plane changes, then each pinpointed focus value that obtains is different with comparing in the past.Therefore this operation is a more complicated and time-consuming.
If adopt Focal (Focus Calibration using Alignment) measurement technology, by obtaining the lens of exposure bench, the parameter of various aspects such as crystal wafer platform, come the variation of monitoring exposure machine focal plane, though can reach very high measurement precision, but in this process, exposure bench can not carry out normal exposure work, exposure bench need be carried, and exposure bench is carried time of getting off just need about 40 minutes, owing to will take exposure bench, so can not carry out the exposing wafer of next group, cause the production capacity of wafer to reduce.
Summary of the invention
In view of this, fundamental purpose of the present invention is to provide a kind of method of monitoring exposure machine focal plane variation, and this method can be under the situation that does not take exposure bench, and monitoring exposure machine focal plane changes quickly and accurately.
For achieving the above object, technical scheme of the present invention specifically is achieved in that
The invention discloses the method that a kind of monitoring exposure machine focal plane changes, comprise the corresponding relation that side wall angle SWA and focal length are set and fit out described corresponding relation curve, this method also comprises: in the exposure bench exposure process, the monitoring side wall angle, determine the pairing focal length value of side wall angle the curve from described fitting, determine whether the focal plane changes.
The described concrete grammar that the corresponding relation of side wall angle and focal length is set and fits out described corresponding relation curve is:
Select the different focal point, obtain the side wall angle value of the pairing wafer photoresistance of each focal length film grid pattern, obtain the corresponding relation of side wall angle and focal length;
Obtain the curve that fits of described side wall angle and focal length according to the corresponding relation of side wall angle and focal length.
The concrete grammar of the side wall angle value of the pairing wafer photoresistance of each focal length of described acquisition film grid pattern is: the optics key dimension measurement system that utilizes scatterometer, described wafer photoresistance film grid pattern is carried out optical measurement, obtain the spectrum of described photoresistance film grid pattern; Described spectrum is analyzed, obtained the value of side wall angle.
When specifically being changed to of described exposure machine focal plane: SWA variation 0.5 is spent, focal length variations 20 nanometers.
The time of described acquisition spectrum is 2 to 3 minutes.
The wavelength of described scatterometer is 250 nanometer to 750 nanometers.
The method whether described definite focal plane changes is for making comparisons with the focal length value of setting, and when detecting the pairing focal length value of SWA value departing from described setting focal length value in observation process, the focal plane changes.
As seen from the above technical solutions, the present invention is by setting different focal lengths, under each focal length, measure the side wall angle of its pairing photoresistance film grid pattern then, obtain the side wall angle of photoresistance film grid pattern and the corresponding relation of focal length, thereby obtain the curve that fits of side wall angle and focal length, only need to measure side wall angle (Sidewall Angel, SWA) value, just can determine the value of focal length, promptly can determine the variation of focal length, compared with prior art, can obtain the situation of change of exposure machine focal plane quickly and accurately.
Description of drawings
Fig. 1 utilizes the OCD measurement system of scatterometer for the present invention, obtains the schematic flow sheet of the situation of change of exposure machine focal plane.
Fig. 2 is the curve that fits of the focal length of PMOS pipe of the present invention and SWA.
Fig. 3 is the curve that fits of the focal length of NMOS pipe of the present invention and SWA.
Embodiment
For make purpose of the present invention, technical scheme, and advantage clearer, below with reference to the accompanying drawing embodiment that develops simultaneously, the present invention is described in more detail.
Utilize (the Optical Critical Demension of optics key dimension measurement system of scatterometer among the present invention, OCD), grid pattern to wafer photoresistance film carries out optical measurement, obtain the side wall angle of photoresistance film grid pattern and the corresponding relation of focal length, thereby obtain the curve that fits of side wall angle and focal length, next, only need to measure the variation of SWA value, can obtain the situation of change of exposure machine focal plane quickly and accurately.
The present invention utilizes the OCD measurement system of scatterometer, and the schematic flow sheet of the situation of change of acquisition exposure machine focal plane may further comprise the steps as shown in Figure 1:
Here determining of focal length value still adopts and makes after the FEM wafer, utilizes CD-SEM to measure wafer two dimension CD, obtain under different exposure energy points, and the variation relation curve between CD and the focal length value, thus obtain the optimum focusing value.Here the focal length value of indication can also can be the resulting focal length value of additive method for making the pinpointed focus value that obtains after the FEM wafer among the embodiment.
Focal length and SWA fit curve as shown in Figures 2 and 3.Fig. 2 is the curve that fits of the focal length that measures the PMOS pipe and SWA; Fig. 3 is the curve that fits of the focal length that measures the NMOS pipe and SWA.R among Fig. 2 and Fig. 3
2Respectively be 0.9825,0.9621, statistically, the statistics greater than 0.95 all is that effectively it all is significant promptly fitting curve.From the relation curve of the focal length of Fig. 2 and Fig. 3 and SWA as can be seen, every variation 1 degree of SWA, focal length variations 40nm.And, generally when SWA changes 0.5 degree, just can find to change, corresponding with it, focal length variations 20 nanometers.In the concrete process of using, because size, cycle, the kind of used photoresistance film and the optical source wavelength of thickness and scatterometer of grid are fixed, the formula that comes out of match is unique like this, and the curve equation that fits of PMOS pipe is Y=-22.455X+87.883 in the present embodiment; The curve equation that fits of NMOS pipe is Y=-21.408X+87.689, wherein, is focal length value on the X-axis, is the angle value of SWA on the Y-axis.
The time of monitoring wafer acquisition spectrum is 2 to 3 minutes, and the time of exposed wafer is 10 minutes.In the present embodiment, use be the SCD100 scatterometer, monitoring mode be spectrum ellipse partially (Spectroscopic Ellipsometry, SE), the monitoring wavelength is 250 nanometer to 750 nanometers, the optical measurement time is with oblique incidence.But the present invention is not limited to described example, can certainly adopt other instruments or other modes to monitor, device such as reflectance spectrum measured thin film instrument for example, and the incident mode can also be a vertical incidence.These technology or device are by to tested body (mainly being thin-film body), it in the present embodiment photoresistance film grid pattern, the light that irradiation has multi-wavelength or bandwidth, to the analysis that reflection or diffraction light from tested body comprise polarized condition, come harmless geometric parameter or its correlation parameter that obtains tested body.
Use scatterometer to carry out the accuracy of the SWA of optical measurement in order to verify, in the present embodiment, adopt scatterometer directly wafer coupons to be monitored, can directly test the tangent plane of wafer coupons like this, obtain the value of SWA, this value is carried out optical measurement with adopting scatterometer, and the goodness of fit that fits the SWA value that draws from spectrum is very high.
With respect to the Focal technology, can under the situation that does not take exposure desk, exposure desk be monitored, and with respect to 40 minutes monitoring time of Focal technology, the present invention has significantly reduced monitoring time.Simultaneously, obtain the technology that the pinpointed focus value is monitored with respect to original passing through, just needed about 1 hour time owing to will obtain the pinpointed focus value originally, and because workload is bigger, so can not monitor the variation of focal length value constantly, so the present invention not only reduced monitoring time, and, when SWA changes 0.5 degree, just can observe focal length variations 20 nanometers, so precision improves greatly also.
It should be appreciated by those skilled in the art, scatterometer that is adopted among the present invention and concrete parameter thereof, be not limited to the concrete numerical value shown in the foregoing description, focal length and SWA fit curve, also be not limited to the concrete situation in the foregoing description, according to different process conditions curves subtle change can take place, those skilled in the art obviously can carry out suitable modifications and variations not breaking away from the spirit or scope of the present invention.
Claims (7)
1. the method that changes of a monitoring exposure machine focal plane, comprise the corresponding relation that side wall angle SWA and focal length are set and fit out described corresponding relation curve, this method also comprises: in the exposure bench exposure process, the monitoring side wall angle, determine the pairing focal length value of side wall angle the curve from described fitting, determine whether the focal plane changes.
2. the method for claim 1 is characterized in that, the described concrete grammar that the corresponding relation of side wall angle and focal length is set and fits out described corresponding relation curve is:
Select the different focal point, obtain the side wall angle value of the pairing wafer photoresistance of each focal length film grid pattern, obtain the corresponding relation of side wall angle and focal length;
Obtain the curve that fits of described side wall angle and focal length according to the corresponding relation of side wall angle and focal length.
3. method as claimed in claim 2, it is characterized in that, the concrete grammar of the side wall angle value of the pairing wafer photoresistance of each focal length of described acquisition film grid pattern is: the optics key dimension measurement system that utilizes scatterometer, described wafer photoresistance film grid pattern is carried out optical measurement, obtain the spectrum of described photoresistance film grid pattern; Described spectrum is analyzed, obtained the value of side wall angle.
4. method as claimed in claim 3 is characterized in that, specifically being changed to of described exposure machine focal plane: SWA changes 0.5 when spending, focal length variations 20 nanometers.
5. method as claimed in claim 3 is characterized in that, the time of described acquisition spectrum is 2 to 3 minutes.
6. method as claimed in claim 3 is characterized in that, the wavelength of described scatterometer is 250 nanometer to 750 nanometers.
7. the method for claim 1, it is characterized in that, the method whether described definite focal plane changes is for making comparisons with the focal length value of setting, and when detecting the pairing focal length value of SWA value departing from described setting focal length value in observation process, the focal plane changes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910082351A CN101866111A (en) | 2009-04-14 | 2009-04-14 | Method for monitoring exposure machine focal plane change |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910082351A CN101866111A (en) | 2009-04-14 | 2009-04-14 | Method for monitoring exposure machine focal plane change |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101866111A true CN101866111A (en) | 2010-10-20 |
Family
ID=42957888
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200910082351A Pending CN101866111A (en) | 2009-04-14 | 2009-04-14 | Method for monitoring exposure machine focal plane change |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101866111A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102566315A (en) * | 2012-01-18 | 2012-07-11 | 上海华力微电子有限公司 | Method for detecting offset of focus of lithography machine |
| CN102566321A (en) * | 2012-02-28 | 2012-07-11 | 上海华力微电子有限公司 | Method for monitoring offset of focal length of lithography machine |
| CN109240039A (en) * | 2017-07-10 | 2019-01-18 | 卡尔蔡司Smt有限责任公司 | Inspection device and method for mask of semiconductor lithography |
| CN112666805A (en) * | 2020-12-30 | 2021-04-16 | 江苏友迪电气有限公司 | Focal length testing method and compensation method |
| CN116952545A (en) * | 2023-09-20 | 2023-10-27 | 粤芯半导体技术股份有限公司 | Method and device for monitoring focus offset of photoetching machine, electronic equipment and storage medium |
-
2009
- 2009-04-14 CN CN200910082351A patent/CN101866111A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102566315A (en) * | 2012-01-18 | 2012-07-11 | 上海华力微电子有限公司 | Method for detecting offset of focus of lithography machine |
| CN102566315B (en) * | 2012-01-18 | 2014-02-05 | 上海华力微电子有限公司 | Method for detecting offset of focus of lithography machine |
| CN102566321A (en) * | 2012-02-28 | 2012-07-11 | 上海华力微电子有限公司 | Method for monitoring offset of focal length of lithography machine |
| CN102566321B (en) * | 2012-02-28 | 2014-11-05 | 上海华力微电子有限公司 | Method for monitoring offset of focal length of lithography machine |
| CN109240039A (en) * | 2017-07-10 | 2019-01-18 | 卡尔蔡司Smt有限责任公司 | Inspection device and method for mask of semiconductor lithography |
| CN109240039B (en) * | 2017-07-10 | 2022-11-04 | 卡尔蔡司Smt有限责任公司 | Inspection apparatus and method for mask for semiconductor lithography |
| CN112666805A (en) * | 2020-12-30 | 2021-04-16 | 江苏友迪电气有限公司 | Focal length testing method and compensation method |
| CN116952545A (en) * | 2023-09-20 | 2023-10-27 | 粤芯半导体技术股份有限公司 | Method and device for monitoring focus offset of photoetching machine, electronic equipment and storage medium |
| CN116952545B (en) * | 2023-09-20 | 2023-12-22 | 粤芯半导体技术股份有限公司 | Lithography machine focus offset monitoring method, device, electronic equipment and storage medium |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| TWI765043B (en) | An overlay metrology system and method | |
| US10101674B2 (en) | Methods and apparatus for determining focus | |
| TWI649628B (en) | Differential methods and apparatus for metrology of semiconductor targets | |
| TWI641828B (en) | Method of characterizing structures of interest on semiconductor wafer and semiconductor metrology system | |
| KR101906289B1 (en) | Measuring a process parameter for a manufacturing process involving lithography | |
| JP6723269B2 (en) | System and method for focus determination using a focus sensitive overlay target | |
| TWI671835B (en) | Metrology test structure design and measurement scheme for measuring in patterned structures | |
| US20110246400A1 (en) | System for optical metrology optimization using ray tracing | |
| US20110246141A1 (en) | Method of optical metrology optimization using ray tracing | |
| US9103664B2 (en) | Automated process control using an adjusted metrology output signal | |
| US20110246142A1 (en) | Optimization of ray tracing and beam propagation parameters | |
| EP4025867B1 (en) | System and method for application of harmonic detectivity as a quality indicator for imaging-based overlay measurements | |
| US20200241428A1 (en) | Scaling Metric for Quantifying Metrology Sensitivity to Process Variation | |
| US10969697B1 (en) | Overlay metrology tool and methods of performing overlay measurements | |
| JP5283372B2 (en) | Method for measuring scatterometer aberrations | |
| CN101866111A (en) | Method for monitoring exposure machine focal plane change | |
| US11609088B2 (en) | Systems and methods for measuring patterns on a substrate |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C12 | Rejection of a patent application after its publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20101020 |