CN104568247A - Measuring method and measuring device for membrane stress - Google Patents
Measuring method and measuring device for membrane stress Download PDFInfo
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- CN104568247A CN104568247A CN201310470964.8A CN201310470964A CN104568247A CN 104568247 A CN104568247 A CN 104568247A CN 201310470964 A CN201310470964 A CN 201310470964A CN 104568247 A CN104568247 A CN 104568247A
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- laser
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- reflected light
- film
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- 238000000034 method Methods 0.000 title claims abstract description 34
- 239000012528 membrane Substances 0.000 title abstract 7
- 238000005259 measurement Methods 0.000 claims abstract description 27
- 239000010408 film Substances 0.000 claims description 83
- 239000000758 substrate Substances 0.000 claims description 19
- 239000010409 thin film Substances 0.000 claims description 16
- 230000002950 deficient Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
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Abstract
The invention relates to a measuring method and measuring device for membrane stress and belongs to the technical field of measurement. In the measuring method and the measuring device for membrane stress, at least two laser beams are projected to a membrane to be measured by a laser transmitter, so that after a detector receives reflection light reflected by the membrane, the membrane stress can be corrected according to difference values delta alpha of reflection angles of multiple reflection light, so that an error in measurement can be lowered greatly; besides, the measuring device also includes a revolving mirror group which can project over-ranging reflection light to a laser receiving unit, thereby enlarging the measuring range, and further improving the precision of a measuring result; the measuring device for the membrane stress provided by the invention is simple in structure, low in cost,simple and convenient in application manner of the measuring method and wider in application range.
Description
Technical Field
The invention relates to the technical field of measurement, in particular to the technical field of film stress measurement, and specifically relates to a film stress measurement method and a measurement device.
Background
The current common machine for stress measurement is in an independent offline mode, the measurement substrate is mostly a silicon wafer, a single beam of laser is projected on a film, and only a single reflection angle is measured to calculate a stress value. The measurement is shown in fig. 1.
In this mode, a thin film is deposited on a substrate such as a silicon wafer, and the substrate is deformed due to stress generated by the difference in physical constants between the substrate and the thin film. The deformation caused by the uniformly attached film is expressed as substrate warpage, the difference between the radii of curvature before and after the film attachment is calculated from the laser reflection angle scanned on the substrate to calculate the variation of the radius of curvature, and the film stress S is calculated from the radius of curvature of the substrate by the following equation.
Wherein,hyperbolic elastic coefficient of the substrate; h is the thickness of the substrate; t is the film thickness; r is the radius of curvature of the substrate.
When the light beam moves, the measurement process is affected by the machine itself, vibration, dead spots, the measurement range and resolution of the machine itself, and environmental factors, which may cause errors in the measurement result. Therefore, how to improve the existing measurement mode and reduce the measurement error becomes a problem to be solved in the technical field.
Disclosure of Invention
The present invention is directed to overcome the above-mentioned drawbacks of the prior art, and provides a method and an apparatus for measuring a film stress, which can effectively reduce measurement errors, expand a measurement range, and improve accuracy of a measurement result, and has a simple application, a low cost, and a wide application range.
In order to achieve the above object, the method for measuring film stress of the present invention comprises the following steps:
projecting at least two beams of laser onto a film to be measured;
step (20) detecting the reflected light of the at least two laser beams reflected from the film by a detector;
step (30) respectively calculating the film stress measured corresponding to each reflected light and the difference value delta alpha between the reflection angles of each reflected light according to the reflection angles of at least two beams of laser reflected light;
and (40) correcting the film stress measured by each beam of reflected light based on the difference delta alpha.
In the method for measuring film stress, the step (10) specifically comprises the following steps:
the laser transmitter in the step (11) projects a beam of laser onto a beam splitter;
the beam splitter in the step (12) splits the laser beam into at least two laser beams which are projected to a reflector group;
and (4) the reflector group reflects the at least two laser beams and then projects the reflected laser beams onto the film to be measured.
In the film stress measuring method, the detector comprises a laser receiving unit and a calculation control unit which are connected with each other; the step (20) further comprises: the laser receiving unit receives at least two beams of reflected light reflected from the film;
said step (30) further comprises: the calculation control unit calculates the film stress and the difference value delta alpha between the reflection angles according to the reflection angles of the multiple beams of reflected light, and corrects the film stress based on the difference value delta alpha.
In the film stress measuring method, a rotating mirror group is also arranged on the light path of a plurality of beams of reflected light and is connected with the calculation control unit; the step (20) specifically comprises the following steps:
projecting the reflected light of step (21) onto the rotating mirror group;
and (4) refracting the reflected light by the rotating mirror group and then projecting the refracted light to the laser receiving unit.
In the method for measuring the film stress, the film to be measured is covered on the substrate, and the step (30) specifically comprises the following steps:
the calculation control unit in step (31) controls the rotation angle of the rotating mirror group to project the reflected light beyond the range of the laser receiving unit to the laser receiving unit;
and (4) the calculation control unit calculates and corrects the film stress according to the rotation angle of the rotating mirror group, the refraction ratio of the rotating mirror group, the receiving angle of the reflected light and the difference delta alpha between the reflection angles of the multiple beams of reflected light.
In the method for measuring film stress, the laser receiving unit receives at least three reflected lights reflected from the film, and the method further comprises the following steps between the step (31) and the step (33):
and (32) comparing the received at least three beams of reflected light by the calculation control unit, judging the bad points of the substrate, and rejecting the bad points.
The present invention also provides a thin film stress measuring device, comprising: the laser emitter is used for projecting at least two beams of laser onto the film to be measured; and the detector is used for detecting the reflected light of the at least two laser beams after being reflected from the film and correcting the film stress according to the difference delta alpha between the reflection angles of the reflected light beams.
The film stress measuring device also comprises a light splitter which is used for splitting a laser beam emitted by the laser emitter into at least two laser beams and projecting the laser beams; and the reflector group is used for reflecting at least two beams of laser projected by the light splitter and then projecting the reflected laser onto the film to be measured.
In the film stress measuring device, the detector comprises a laser receiving unit and a calculation control unit which are connected with each other, and the laser receiving unit is used for receiving reflected light reflected from the film; the calculation control unit is used for correcting the film stress according to the difference delta alpha between the reflection angles of the multiple beams of reflected light.
The film stress measuring device also comprises a rotating mirror group, wherein the rotating mirror group is arranged on the light path of the multiple reflected lights, is connected with the calculation control unit, is used for refracting the reflected lights and then projecting the refracted lights to the laser receiving unit, and projects the reflected lights beyond the range of the laser receiving unit to the laser receiving unit under the control of the calculation control unit.
In the film stress measuring device, the film to be measured is covered on a substrate, and the calculation control unit is used for calculating and correcting the film stress according to the rotation angle of the rotating mirror group, the refraction ratio of the rotating mirror group, the receiving angle of the reflected light and the difference delta alpha between the reflection angles of a plurality of beams of reflected light.
In the film stress measuring device, the laser receiving unit receives at least three beams of reflected light reflected from the film, and the calculation control unit is used for judging the defective points of the substrate and eliminating the defective points according to the comparison result of the received at least three beams of reflected light.
By adopting the film stress measuring method and the measuring device, the laser emitter projects at least two beams of laser to the film to be measured, so that the detector can correct the film stress measured by each beam of reflected light according to the difference delta alpha between the reflection angles of a plurality of beams of reflected light after receiving the reflected light reflected by the film, thereby effectively reducing the measuring error; meanwhile, the measuring device also comprises a rotating lens group which can project the reflected light beyond the range to the laser receiving unit so as to enlarge the measuring range and further improve the accuracy of the measuring result.
Drawings
Fig. 1 is a schematic structural diagram of a thin film stress measurement device in the prior art.
FIG. 2 is a schematic structural diagram of a thin film stress measurement device according to the present invention.
FIG. 3 is a flowchart illustrating steps of a method for measuring film stress according to the present invention.
Detailed Description
In order to clearly understand the technical contents of the present invention, the following examples are given in detail.
Fig. 2 is a schematic structural diagram of a thin film stress measuring device according to the present invention.
In one embodiment, as shown in fig. 2, the thin film stress measuring apparatus of the present invention includes a laser emitter 1 and a detector 2.
The method for measuring the film stress by using the device of this embodiment, as shown in fig. 3, includes the following steps:
step (10), the laser transmitter 1 projects at least two beams of laser onto the film 3 to be measured;
step (20) the detector 2 detects the reflected light of the at least two laser beams reflected from the film 3;
step (30) respectively calculating the film stress measured corresponding to each reflected light beam and the difference value delta alpha between the reflection angles of the reflected light beams according to the reflection angles of the reflected light beams;
and (40) correcting the film stress measured by each beam of reflected light based on the difference delta alpha.
In a preferred embodiment, the thin film stress measuring device further comprises: a beam splitter 4 and a mirror group 5.
In the method for measuring a film stress using the apparatus of the preferred embodiment, the step (10) specifically includes the steps of:
the laser transmitter 1 in the step (11) projects a beam of laser onto a beam splitter 4;
the beam splitter 4 in the step (12) splits the laser beam into at least two laser beams, and the two laser beams are projected to a reflector group 5;
and (5) reflecting the at least two laser beams by the reflector group 5 and then projecting the reflected laser beams onto the film 3 to be measured.
In a further preferred embodiment, the detector 2 comprises a laser receiving unit 21 and a calculation control unit (not shown in the figure) connected to each other.
In the method for measuring a film stress using the apparatus of the further preferred embodiment, the step (20) is specifically: the laser receiving unit 21 receives at least two beams of reflected light reflected from the film 3; the step (30) is specifically as follows: the calculation control unit calculates the film stress and the difference value delta alpha between the reflection angles according to the reflection angles of the multiple beams of reflected light, and corrects the film stress based on the difference value delta alpha.
In a further preferred embodiment, the thin film stress measuring apparatus further comprises a rotating mirror group 6, wherein the rotating mirror group 6 is disposed on the optical path of the plurality of reflected lights and connected to the calculation control unit. The film 3 to be measured is covered on the substrate 7.
In the method for measuring a film stress using the apparatus of the further preferred embodiment, the step (20) specifically includes the steps of:
projecting the reflected light of the step (21) onto the rotating mirror group 6;
the reflected light in step (22) is refracted by the rotating mirror group 6 and then is projected to the laser receiving unit 21.
And the step (30) specifically comprises the following steps:
the calculation control unit in step (31) controls the rotation angle of the rotating mirror group 6 to project the reflected light beyond the range of the laser receiving unit 21 to the laser receiving unit 21;
and (4) the calculation control unit calculates and corrects the film stress according to the rotation angle of the rotating mirror group 6, the refraction ratio of the rotating mirror group 6, the receiving angle of the reflected light and the difference delta alpha between the reflection angles of the multiple beams of reflected light.
In a more preferred embodiment, the laser receiving unit receives at least three reflected lights reflected from the film 3.
In the method for measuring a film stress using the apparatus of the preferred embodiment, the method further comprises the following steps between step (31) and step (33):
and (4) comparing the received at least three beams of reflected light by the calculation control unit, judging the defective points of the substrate 7 and eliminating the defective points.
In practical application, the method and the device for measuring the film stress change single laser beam measurement into multi-beam measurement on the basis of the existing measurement principle, simultaneously detect the difference value of the reflection angles of the light beams to correct the stress value, and add the rotary mirror group, process the refracted light beams by the rotation of the mirror group, enlarge the reflection angles, refract the reflected light, facilitate the detection of the light beams beyond the measurement range, adjust the rotation of the rotary mirror group along with the received light signals, and eliminate the dead spots after analyzing the dead spots of the substrate by comparison. The rotating lens group is connected with a control computer, the rotation angle of the lens group, the refractive ratio row of the lens group and the size of the reflected light receiving angle are detected, and the film stress is calculated and corrected through a formula.
The film stress measuring method and the film stress measuring device have the advantages that:
1. the multi-beam measurement is relative to the single-beam measurement, the difference delta alpha of the reflection angles of the multi-beam measurement is taken to correct the stress, so that the vibration can be reduced, the influence of environmental factors on the measurement result can be eliminated, and the result is more accurate;
2. three groups of data are obtained simultaneously, bad points are eliminated through comparison and analysis, and the precision is relatively improved;
3. a rotating lens group is additionally arranged, the reflection angle is proportionally enlarged, and the detection result is better and more accurate;
4. the rotary lens group is additionally arranged to refract light beams beyond the measuring range, so that the measuring range of the machine is enlarged.
By adopting the film stress measuring method and the measuring device, the laser emitter projects at least two beams of laser to the film to be measured, so that the detector can calculate the film stress according to the difference delta alpha between the reflection angles of a plurality of beams of reflected light after receiving the reflected light reflected by the film, thereby effectively reducing the measuring error; meanwhile, the measuring device also comprises a rotating lens group which can project the reflected light beyond the range to the laser receiving unit so as to enlarge the measuring range and further improve the accuracy of the measuring result.
In this specification, the invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.
Claims (10)
1. A method for measuring film stress is characterized in that the method comprises the following steps:
projecting at least two beams of laser onto a film to be measured;
step (20) detecting the reflected light of the at least two laser beams reflected from the film by a detector;
step (30) respectively calculating the film stress measured corresponding to each reflected light and the difference value delta alpha between the reflection angles of each reflected light according to the reflection angles of at least two beams of laser reflected light;
and (40) correcting the film stress measured by each beam of reflected light based on the difference delta alpha.
2. The method of claim 1, wherein the step (10) further comprises the steps of:
step (11) projecting a laser beam onto a beam splitter;
the beam splitter in the step (12) splits the laser beam into at least two laser beams which are projected to a reflector group;
and (4) the reflector group reflects the at least two laser beams and then projects the reflected laser beams onto the film to be measured.
3. The method of claim 1 or 2, wherein the detector comprises a laser receiver and a calculation controller connected to each other; the step (20) further comprises: the laser receiving unit receives at least two beams of reflected light reflected from the film;
said step (30) further comprises: the calculation control unit calculates the film stress and the difference value delta alpha between the reflection angles according to the reflection angles of the multiple beams of reflected light, and corrects the film stress based on the difference value delta alpha.
4. The method of claim 3, wherein a rotating mirror is further disposed on each of the light paths of the reflected lights, and the rotating mirror is connected to the calculation control unit; the step (20) specifically comprises the following steps:
projecting the reflected light of step (21) onto the rotating mirror group;
and (4) refracting the reflected light by the rotating mirror group and then projecting the refracted light to the laser receiving unit.
5. The method of claim 3, wherein the film to be measured is covered on a substrate, and the step (30) comprises the following steps:
the calculation control unit in step (31) controls the rotation angle of the rotating mirror group to enable the reflected light exceeding the range of the laser receiving unit to be projected to the laser receiving unit;
and (4) the calculation control unit calculates and corrects the film stress according to the rotation angle of the rotating mirror group, the refraction ratio of the rotating mirror group, the receiving angle of the reflected light and the difference delta alpha between the reflection angles of the reflected lights.
6. The method of claim 5, wherein the laser receiving unit receives at least three reflected lights reflected from the thin film, and the method further comprises the following steps between the step (31) and the step (33):
and (32) comparing the received at least three beams of reflected light by the calculation control unit, judging the bad points of the substrate, and rejecting the bad points.
7. A thin film stress measuring device, comprising:
the laser emitter is used for projecting at least two beams of laser onto the film to be measured; and
and the detector is used for detecting the reflected light of the at least two laser beams after being reflected from the film and correcting the film stress according to the difference delta alpha between the reflection angles of the reflected light beams.
8. The thin film stress measurement device of claim 7, further comprising:
the beam splitter is used for splitting a laser beam emitted by the laser emitter into at least two laser beams and projecting the laser beams; and
and the reflector group is used for reflecting at least two beams of laser projected by the light splitter and then projecting the reflected laser onto the film to be measured.
9. The apparatus according to claim 7 or 8, wherein the detector comprises a laser receiving unit connected to each other for receiving the reflected light reflected from the thin film and a calculation control unit for correcting the stress of the thin film according to a difference Δ α between the reflection angles of the reflected light beams.
10. The thin film stress measuring device of claim 9, further comprising:
and the rotating mirror group is arranged on the light path of the multiple reflected lights, is connected with the calculation control unit, is used for refracting the reflected lights and then projecting the refracted lights to the laser receiving unit, and projects the reflected lights beyond the range of the laser receiving unit to the laser receiving unit under the control of the calculation control unit.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310470964.8A CN104568247B (en) | 2013-10-10 | 2013-10-10 | Measuring method and measuring device for membrane stress |
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| CN201310470964.8A CN104568247B (en) | 2013-10-10 | 2013-10-10 | Measuring method and measuring device for membrane stress |
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| CN104568247A true CN104568247A (en) | 2015-04-29 |
| CN104568247B CN104568247B (en) | 2017-05-17 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107144383A (en) * | 2017-03-15 | 2017-09-08 | 上海大学 | Membrane stress test device and film stress test method |
| CN110068405A (en) * | 2019-03-29 | 2019-07-30 | 上海理工大学 | A kind of optical pressure sensor |
| CN110542536A (en) * | 2019-09-24 | 2019-12-06 | 上海交通大学 | Single-degree-of-freedom micro-force measurement system for soap film water tunnel model experiment |
| CN113267278A (en) * | 2021-05-24 | 2021-08-17 | 无锡卓海科技有限公司 | Film stress measuring instrument and measuring method thereof |
| CN116202664A (en) * | 2023-03-10 | 2023-06-02 | 无锡卓海科技股份有限公司 | Film stress detection system and method suitable for transparent wafer |
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| US5134303A (en) * | 1990-08-14 | 1992-07-28 | Flexus, Inc. | Laser apparatus and method for measuring stress in a thin film using multiple wavelengths |
| JP2000028441A (en) * | 1998-06-22 | 2000-01-28 | Saint Gobain Vitrage | Method for measuring film of transparent material and device for implementing the same |
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2013
- 2013-10-10 CN CN201310470964.8A patent/CN104568247B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5134303A (en) * | 1990-08-14 | 1992-07-28 | Flexus, Inc. | Laser apparatus and method for measuring stress in a thin film using multiple wavelengths |
| JP2000028441A (en) * | 1998-06-22 | 2000-01-28 | Saint Gobain Vitrage | Method for measuring film of transparent material and device for implementing the same |
Non-Patent Citations (2)
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107144383A (en) * | 2017-03-15 | 2017-09-08 | 上海大学 | Membrane stress test device and film stress test method |
| CN110068405A (en) * | 2019-03-29 | 2019-07-30 | 上海理工大学 | A kind of optical pressure sensor |
| CN110542536A (en) * | 2019-09-24 | 2019-12-06 | 上海交通大学 | Single-degree-of-freedom micro-force measurement system for soap film water tunnel model experiment |
| CN113267278A (en) * | 2021-05-24 | 2021-08-17 | 无锡卓海科技有限公司 | Film stress measuring instrument and measuring method thereof |
| CN113267278B (en) * | 2021-05-24 | 2022-12-09 | 无锡卓海科技股份有限公司 | Film stress measuring instrument and measuring method thereof |
| CN116202664A (en) * | 2023-03-10 | 2023-06-02 | 无锡卓海科技股份有限公司 | Film stress detection system and method suitable for transparent wafer |
| CN116202664B (en) * | 2023-03-10 | 2023-11-10 | 无锡卓海科技股份有限公司 | Wafer film stress detection system and method |
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Address after: 201508, building two, building 100, 1, Jinshan Industrial Road, 208, Shanghai, Jinshan District Patentee after: Shanghai Hehui optoelectronic Co.,Ltd. Address before: 201508, building two, building 100, 1, Jinshan Industrial Road, 208, Shanghai, Jinshan District Patentee before: EverDisplay Optronics (Shanghai) Ltd. |
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