CN105910530A - Wafer parallelism testing method - Google Patents
Wafer parallelism testing method Download PDFInfo
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- CN105910530A CN105910530A CN201610267887.XA CN201610267887A CN105910530A CN 105910530 A CN105910530 A CN 105910530A CN 201610267887 A CN201610267887 A CN 201610267887A CN 105910530 A CN105910530 A CN 105910530A
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- 238000012360 testing method Methods 0.000 title claims abstract description 135
- 239000002184 metal Substances 0.000 claims description 123
- 239000000523 sample Substances 0.000 claims description 41
- 238000000034 method Methods 0.000 claims description 10
- 230000008878 coupling Effects 0.000 claims description 6
- 238000010168 coupling process Methods 0.000 claims description 6
- 238000005859 coupling reaction Methods 0.000 claims description 6
- 230000007423 decrease Effects 0.000 claims description 6
- 235000012431 wafers Nutrition 0.000 description 129
- 230000005684 electric field Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 230000003247 decreasing effect Effects 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/02—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness
- G01B7/06—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness for measuring thickness
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Testing Or Measuring Of Semiconductors Or The Like (AREA)
Abstract
The invention provides a wafer parallelism testing method in which a wafer frequency testing device is employed to conduct frequency tests on test areas preset on the wafer to form amplitude frequency curves for the test areas. Based on the amplitude frequency curves for the test areas, the resonant frequencies of the test areas are determined. According to the relationship between the resonant frequencies and the thicknesses, the thicknesses of the test areas are determined. Finally, the parallelism of the wafer is determined according to the thicknesses of the test areas. With the invention, damage to a wafer can be reduced in testing the performance of the wafer while the testing accuracy on parallelism is raised.
Description
Technical Field
The invention belongs to the technical field of wafer manufacturing production, and particularly relates to a wafer parallelism testing method.
Background
With the development of electronic manufacturing industry, wafers are widely used in electronic manufacturing, and how to effectively test the performance of the wafers so as to obtain qualified wafers becomes a concern. At present, when the parallelism of the wafer is tested, a micrometer is usually required to be used for tightly pressing the wafer, and the wafer can be damaged.
Disclosure of Invention
The invention provides a wafer parallelism testing method, which aims to solve the problem that a wafer is easy to damage when the wafer is tested for parallelism at present.
According to a first aspect of the embodiments of the present invention, there is provided a wafer parallelism testing method, including:
the wafer frequency testing device comprises a metal probe, a metal table top, a fixing frame and a frequency testing instrument, wherein the top end of the metal probe is connected with the fixing frame through an elastic component, a metal sheet parallel to the metal table top is arranged at the bottom end of the metal probe, the frequency testing instrument is used for sequentially applying alternating current power supplies with different frequencies between the metal table top and the metal sheet, and measuring the amplitude of each testing area sequentially arranged between the metal sheet and the metal table top under the alternating current power supplies with different frequencies, so that an amplitude-frequency curve of each testing area is formed;
determining the resonant frequency of each test area according to the amplitude-frequency curve of each test area;
determining the thickness of each test area according to the corresponding relation between the resonance frequency and the thickness in the wafer;
and determining the parallelism of the wafer according to the thickness of each test area.
In an alternative implementation, the area of the metal sheet decreases with increasing expected resonant frequency, electromechanical coupling coefficient of the wafer, decreases with decreasing wafer size and is smaller than the area of the wafer.
In another alternative implementation manner, the metal probe is fixed in the fixing frame in a threaded connection manner.
In another alternative implementation, the measuring end of the frequency testing instrument is connected to any one of the elastic component, the metal probe and the metal sheet to measure the amplitude of the wafer placed between the metal sheet and the metal table.
In another optional implementation manner, the area of the test region is larger than the area of a metal sheet in the wafer frequency testing device.
In another optional implementation manner, the determining the resonant frequency of each test region according to the amplitude-frequency curve of each test region includes:
and aiming at the amplitude-frequency curve of each test area, taking the frequency corresponding to the highest amplitude point in the amplitude-frequency curve as the resonant frequency of the test area.
In another optional implementation manner, the determining the parallelism of the wafer according to the thickness of each test area includes:
subtracting the thicknesses of the test areas from each other;
judging whether the maximum difference value and the minimum difference value after the subtraction of every two are within a preset range;
and if so, determining that the parallelism of the wafer is good.
The invention has the beneficial effects that:
1. in the wafer frequency testing device, the frequency testing instrument sequentially applies alternating current power supplies with different frequencies between the metal table top in contact with the wafer and the metal sheet right above the wafer, so alternating current electric fields with different frequencies can be formed between the metal sheet and the metal table top, the wafer can vibrate under the alternating current electric fields with different frequencies, in addition, the metal sheet is fixed at the bottom end of the metal probe, the top end of the metal probe is connected with the fixing frame through the elastic component, and the elastic component can provide upward pulling force for the metal probe in the vibration process of the wafer, so that the influence of the metal probe and the metal sheet on the vibration of the wafer can be reduced, the amplitude tested by the frequency testing instrument can more accurately reflect the actual vibration condition of the wafer, and the testing accuracy of the wafer resonant frequency can be improved; in addition, the metal sheet is fixed at the bottom end of the metal probe, and the top end of the metal probe is connected with the fixing frame through the elastic component, so that the metal sheet, the wafer and the metal table top can be in good contact with each other after the wafer is placed between the metal sheet and the metal table top, but the wafer is not damaged; according to the invention, when the parallelism of the wafer is determined, firstly, the wafer frequency testing device is adopted to carry out frequency testing on the wafer to obtain the resonant frequency of the wafer, then the thickness of the wafer is determined based on the resonant frequency of the wafer, and the parallelism of the wafer is determined according to the thickness of the wafer;
2. the invention can improve the frequency test accuracy of the wafer by reducing the area of the metal sheet along with the increase of the expected resonant frequency and the electromechanical coupling coefficient of the wafer and the reduction of the size of the wafer;
3. according to the invention, the metal probe is fixed in the fixing frame in a threaded connection manner, so that a tester can conveniently replace the metal sheet according to the expected resonance frequency, the electromechanical coupling coefficient and the size of the wafer, and the application range of the wafer frequency testing device can be enlarged;
4. the invention can reduce the influence of the amplitude measurement process on the vibration of the wafer by connecting the measuring end of the frequency testing instrument with the elastic component or the metal probe or the metal sheet which can reflect the vibration condition of the wafer instead of directly connecting the wafer;
5. according to the invention, the frequency test accuracy of each test region can be improved by enabling the area of the test region to be larger than that of the metal sheet, so that the parallelism test accuracy of the wafer can be improved.
Drawings
FIG. 1 is a flow chart of one embodiment of a wafer parallelism testing method in accordance with the invention;
FIG. 2 is a block diagram of an embodiment of a wafer frequency testing apparatus according to the present invention.
Detailed Description
In order to make the technical solutions in the embodiments of the present invention better understood and make the above objects, features and advantages of the embodiments of the present invention more comprehensible, the technical solutions in the embodiments of the present invention are described in further detail below with reference to the accompanying drawings.
In the description of the present invention, unless otherwise specified and limited, it is to be noted that the term "connected" is to be interpreted broadly, and may be, for example, a mechanical connection or an electrical connection, or a communication between two elements, or may be a direct connection or an indirect connection through an intermediate medium, and a specific meaning of the term may be understood by those skilled in the art according to specific situations.
Referring to fig. 1, a flowchart of an embodiment of a wafer parallelism testing method according to the invention is shown. The wafer parallelism testing method can comprise the following steps:
step S101, a wafer frequency testing device is adopted to carry out frequency testing on each testing area preset on the wafer. The wafer frequency testing apparatus may include a metal probe 110, a metal table 120, a fixing frame 130, and a frequency testing instrument 140, as shown in fig. 1, wherein a top end of the metal probe 110 may be connected to the fixing frame 130 through an elastic component 150, the top end may be provided with a metal sheet 160 parallel to the metal table 120, and the frequency testing instrument 140 may be configured to apply ac power with different frequencies between the metal table 120 and the metal sheet 160 in sequence, and measure amplitudes of various testing regions on the wafer 170 sequentially placed between the metal sheet 160 and the metal table 120 under the ac power with different frequencies, so as to form an amplitude-frequency curve of each testing region.
In this embodiment, it is found through research that the correspondence between the resonant frequency and the thickness of the wafer can be expressed as:
wherein,
t is the thickness of the wafer;
Kf-wafer shear vibration frequency constant;
f0-the resonance frequency of the wafer;
the invention therefore proposes to determine the thickness of the wafer and thus the parallelism of the wafer on the basis of the resonance frequency of the individual test areas on the wafer.
At present, when testing the frequency performance of a wafer, a "contact" test method is generally adopted, that is, two metal probes are generally used to press the wafer first, then an ac power is applied to the two metal probes respectively, and the resonance frequency of the wafer is determined according to the combined amplitude of the two metal probes and the wafer under different ac power frequencies. However, this method may cause damage to the wafer when two metal probes are pressed against the wafer, and it has been found through research that the resonance frequency of the wafer tested by this method is lower than the actual resonance frequency of the wafer, i.e., the accuracy of the resonance frequency of the wafer tested by this method is lower. By adopting an air gap test method, the upper metal probe is away from the surface of the wafer for a certain distance to induce the vibration of the wafer, so that certain energy loss is caused, the amplitude-frequency curve tested on a frequency test instrument has weak response, the frequency point corresponding to the maximum amplitude is inaccurate, and the resonant frequency of the wafer cannot be accurately tested.
In this embodiment, before testing the frequency characteristics of each test region on the wafer, the elastic component 150 connected to the top end of the metal probe 110 may be in a tensile state, and a predetermined distance (which may be smaller than the designed thickness of the corresponding wafer) may exist between the metal sheet 160 connected to the bottom end of the metal probe 110 and the metal mesa 120. Thus, when each test area on the wafer 170 is placed between the metal sheet 160 and the metal mesa 120, the metal sheet 160, the wafer 170, and the metal mesa 120 can be in good contact with each other without causing damage to the wafer 170.
When testing the frequency performance of each test region on the wafer, the corresponding test region on the wafer 170 may be first placed between the metal sheet 160 and the metal table 120, then the frequency testing instrument 140 is controlled to provide ac power with different frequencies between the metal table 120 and the metal sheet 160, and the amplitude of the test region is measured under the ac power with different frequencies, so as to form an amplitude-frequency curve of the test region. Thereafter, the frequency corresponding to the highest amplitude point in the amplitude-frequency curve can be used as the resonant frequency of the test region 170.
It is found that when the metal sheets with the same area are used for frequency testing wafers with different expected resonant frequencies, different materials and different sizes, the frequency testing accuracy is different. The frequency testing accuracy of the wafer can be improved by generally decreasing the sheet metal area as the expected resonant frequency, the electromechanical coupling coefficient (which can be used to characterize the wafer material), of the wafer increases, and the frequency testing accuracy of the wafer can also be improved by decreasing the sheet metal area as the wafer size decreases. In this embodiment, the metal probes 110 may be fixed in the fixing frame 130 by a threaded connection, and when the area of the metal sheet disposed at the bottom end of each metal probe is different, the metal sheet with different area may be replaced by replacing the metal probe. According to the invention, the metal probe is fixed in the fixing frame in a threaded connection manner, so that a tester can conveniently replace the metal sheet according to the expected resonant frequency, the electromechanical coupling coefficient and the size of the wafer, and the application range of the wafer frequency testing device can be enlarged.
In the wafer frequency testing device, the frequency testing instrument sequentially applies alternating current power supplies with different frequencies between the metal table top in contact with the wafer and the metal sheet right above the wafer, so alternating current electric fields with different frequencies can be formed between the metal sheet and the metal table top, the wafer can vibrate under the alternating current electric fields with different frequencies, in addition, the metal sheet is fixed at the bottom end of the metal probe, the top end of the metal probe is connected with the fixing frame through the elastic component, and the elastic component can provide upward pulling force for the metal probe in the vibration process of the wafer, so that the influence of the metal probe and the metal sheet on the vibration of the wafer can be reduced, the amplitude tested by the frequency testing instrument can more accurately reflect the actual vibration condition of the wafer, and the testing accuracy of the wafer resonant frequency can be improved. In addition, the metal sheet is fixed at the bottom end of the metal probe, and the top end of the metal probe is connected with the fixing frame through the elastic component, so that the metal sheet, the wafer and the metal table top can be in good contact with each other after the wafer is placed between the metal sheet and the metal table top, and the wafer cannot be damaged.
It should be noted that: the elastic component 150 may be a spring, a sponge, etc., and since the metal sheet 160 is connected to the fixing frame through the metal probe 110 and the elastic component 150, the wafer 170 may drive the metal sheet 160, the metal probe 110 and the elastic component 150 to vibrate while vibrating, so that the frequency measuring instrument 140 may connect the measuring end thereof to any one of the elastic component 150, the metal probe 110 and the metal sheet 160 when measuring the amplitude of the wafer. The invention can reduce the influence of the amplitude measurement process on the vibration of the wafer by connecting the measuring end of the frequency testing instrument with the elastic component or the metal probe or the metal sheet which can reflect the vibration condition of the wafer instead of directly connecting the wafer.
In addition, when the parallelism of the wafer is tested, the same wafer frequency testing device can be adopted to sequentially test each preset testing area on the wafer, so that the flatness of different areas of the metal table top in different wafer frequency testing devices and the same wafer frequency testing device can be reduced, the influence on the measurement of the parallelism of the wafer is reduced, and the accuracy of the test of the parallelism of the wafer can be improved.
And S102, respectively determining the resonant frequency of each test area according to the amplitude-frequency curve of each test area.
In this embodiment, after obtaining the amplitude-frequency curve of each test region, for the amplitude-frequency curve of each test region, a frequency corresponding to a highest amplitude point in the amplitude-frequency curve may be used as the resonant frequency of the test region.
Step S103, determining the thickness of each test area according to the corresponding relation between the resonance frequency and the thickness in the wafer.
And step S104, determining the parallelism of the wafer according to the thickness of each test area.
In this embodiment, when determining the parallelism of the wafer, the thicknesses of the test areas may be subtracted from each other; and then judging whether the maximum difference value and the minimum difference value after the subtraction of every two are within a preset range, if so, determining that the parallelism of the wafer is good, and otherwise, determining that the parallelism of the wafer is unqualified.
It should be noted that: when dividing the test area of the wafer, the area of the test area of the wafer is generally made larger than the area of the metal sheet. When the area of the metal sheet is larger than that of the test area, the mass load of the test area is increased when the frequency test is performed on the test area, which may cause the resonant frequency of the test area obtained by the test to be smaller than the actual resonant frequency, thereby causing the frequency test accuracy of the test area to be lower. Therefore, the frequency testing accuracy of each testing area can be improved by enabling the area of the testing area to be larger than that of the metal sheet, and the parallelism testing accuracy of the wafer can be improved.
It can be seen from the above embodiments that, when determining the parallelism of a wafer, the present invention first performs a frequency test on each test area on the wafer using the wafer frequency test apparatus to obtain a resonant frequency of each test area, then determines the thickness of the wafer based on the resonant frequency of each test area, and determines the parallelism of the wafer according to the thickness of the wafer.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.
Claims (7)
1. A wafer parallelism testing method is characterized by comprising the following steps:
the wafer frequency testing device comprises a metal probe, a metal table top, a fixing frame and a frequency testing instrument, wherein the top end of the metal probe is connected with the fixing frame through an elastic component, a metal sheet parallel to the metal table top is arranged at the bottom end of the metal probe, the frequency testing instrument is used for sequentially applying alternating current power supplies with different frequencies between the metal table top and the metal sheet, and measuring the amplitude of each testing area sequentially arranged between the metal sheet and the metal table top under the alternating current power supplies with different frequencies, so that an amplitude-frequency curve of each testing area is formed;
determining the resonant frequency of each test area according to the amplitude-frequency curve of each test area;
determining the thickness of each test area according to the corresponding relation between the resonance frequency and the thickness in the wafer;
and determining the parallelism of the wafer according to the thickness of each test area.
2. The apparatus of claim 1, wherein the area of the metal sheet decreases as the expected resonant frequency, electromechanical coupling coefficient of the wafer increases, decreases as the wafer size decreases and the area of the metal sheet is smaller than the area of the wafer.
3. The device of claim 1, wherein the metal probe is secured in the holder by a threaded connection.
4. The apparatus of claim 1, wherein a measuring end of the frequency testing instrument is connected to any one of the spring assembly, the metal probe and the metal plate to measure an amplitude of a wafer placed between the metal plate and the metal table.
5. The method of claim 1, wherein the area of the test region is larger than the area of a metal sheet in the wafer frequency testing device.
6. The method of claim 1, wherein determining the resonant frequency of each test region from the amplitude-frequency curve of each test region comprises:
and aiming at the amplitude-frequency curve of each test area, taking the frequency corresponding to the highest amplitude point in the amplitude-frequency curve as the resonant frequency of the test area.
7. The method of claim 1, wherein said determining parallelism of said wafer based on said thickness of said respective test area comprises:
subtracting the thicknesses of the test areas from each other;
judging whether the maximum difference value and the minimum difference value after the subtraction of every two are within a preset range;
and if so, determining that the parallelism of the wafer is good.
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| JPH0734248A (en) * | 1993-07-23 | 1995-02-03 | Toyota Motor Corp | Quartz crystal type film thickness gage |
| US20060137452A1 (en) * | 2003-04-21 | 2006-06-29 | Tangidyne Corporation | Method and apparatus for measuring film thickness and film thickness growth |
| CN202473871U (en) * | 2012-02-09 | 2012-10-03 | 青岛嘉星晶电科技股份有限公司 | Measurement device for surface evenness of wafer |
| CN103217115A (en) * | 2012-01-19 | 2013-07-24 | 昆山思拓机器有限公司 | Measuring device for wafer thickness and wafer planeness |
| CN203325845U (en) * | 2013-07-05 | 2013-12-04 | 天津浩洋环宇科技有限公司 | Tool used for wafer surface flatness measurement |
-
2016
- 2016-04-26 CN CN201610267887.XA patent/CN105910530A/en active Pending
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|---|---|---|---|---|
| JPS5223960A (en) * | 1975-08-19 | 1977-02-23 | Matsushita Electric Ind Co Ltd | Process for measuring piezo-electric thickness resonator |
| US4362125A (en) * | 1980-07-21 | 1982-12-07 | Balzers Aktiengesellschaft | Quartz oscillator measuring head |
| JPH0734248A (en) * | 1993-07-23 | 1995-02-03 | Toyota Motor Corp | Quartz crystal type film thickness gage |
| US20060137452A1 (en) * | 2003-04-21 | 2006-06-29 | Tangidyne Corporation | Method and apparatus for measuring film thickness and film thickness growth |
| CN103217115A (en) * | 2012-01-19 | 2013-07-24 | 昆山思拓机器有限公司 | Measuring device for wafer thickness and wafer planeness |
| CN202473871U (en) * | 2012-02-09 | 2012-10-03 | 青岛嘉星晶电科技股份有限公司 | Measurement device for surface evenness of wafer |
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Non-Patent Citations (2)
| Title |
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| 史天录，刘经燕: "《测试技术及应用》", 31 May 2009 * |
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Application publication date: 20160831 |