JP2014052291A - Gain calibration sample, film thickness measurement device, and gain calibration method - Google Patents

Abstract

A gain calibration sample capable of accurately adjusting the height of a measurement head is provided.
A gain calibration sample (60) includes a height adjustment unit (61) and a gain adjustment unit (62). The height adjusting unit (61) is a part for adjusting the height of the measuring head by measurement of the displacement sensor. The gain adjustment unit (62) is a part for adjusting the gain of the measurement head.
[Selection] Figure 7A

Description

  The present invention relates to a gain calibration sample, a film thickness measuring device, and a gain calibration method.

  Conventionally, as a gain calibration sample used in a film thickness measuring device, there is one described in Japanese Patent Laid-Open No. 2005-156213 (Patent Document 1). As shown in FIG. 9, the calibration sample 100 includes a sample material 101 and a glass 102 that covers the sample material 101.

  By the way, when the calibration sample 100 is used to adjust the gain of the measurement head for measuring the film thickness of the film thickness measurement device, first, the distance between the measurement head and the calibration sample 100 is set in advance. It is necessary to adjust the position of the measuring head in the height direction so as to be a value.

  At this time, the distance from the calibration sample 100 is measured by the displacement sensor of the film thickness measuring apparatus, and the position of the measuring head in the height direction is adjusted based on the measured value. The displacement sensor irradiates the calibration sample 100 with a light beam, detects reflected light from the calibration sample 100, and measures the distance from the calibration sample 100.

  However, since the light from the displacement sensor is reflected more on the lower surface 102b than on the upper surface 102a of the glass 102, the displacement sensor measures the distance to the lower surface 102b instead of the upper surface 102a of the glass 102. For this reason, the distance between the measurement head and the calibration sample 100 becomes smaller than the set value, and there is a problem that the height of the measurement head cannot be adjusted accurately. For this reason, the gain of the measurement head cannot be adjusted accurately.

JP 2005-156213 A

  Accordingly, an object of the present invention is to provide a gain calibration sample, a film thickness measurement device, and a gain calibration method that can accurately adjust the height of a measurement head.

In order to solve the above problems, the gain calibration sample of the present invention is
A calibration sample used for calibration of a film thickness measuring device having a displacement sensor for measuring a distance from a formed product substrate and a measurement head for measuring the thickness of the film of the product substrate,
A height adjusting unit for adjusting the height of the measuring head by measurement of the displacement sensor;
And a gain adjusting unit for adjusting the gain of the measuring head.

  Here, the product substrate includes a substrate and one or more films formed on the substrate.

  According to the gain calibration sample of the present invention, since the height adjustment unit and the gain adjustment unit are provided, the height of the measurement head can be adjusted at a portion different from the adjustment of the gain of the measurement head. . Thereby, the height of the measuring head can be adjusted accurately.

Moreover, in the film thickness measuring device of one embodiment,
The base,
A substrate stage that is provided on the base and on which the formed product substrate is placed;
A calibration stage provided on the base and on which the gain calibration sample according to claim 1 is placed;
A gantry that extends in a first direction with respect to the substrate stage and the calibration stage and is attached to the base so as to be movable in a second direction with respect to the substrate stage and the calibration stage;
A slider attached to the gantry movably in the first direction;
A displacement sensor that is fixed to the slider and measures a distance from the product substrate placed on the substrate stage;
A measuring head fixed to the slider and measuring the thickness of the film of the product substrate placed on the substrate stage;
The displacement sensor and the measurement head are moved to the calibration stage, the height adjustment unit of the gain calibration sample is used to adjust the height of the measurement head by measuring the displacement sensor, and then the gain calibration is performed. Measuring instrument calibration means for adjusting the gain of the measuring head using the gain adjusting section of the sample.

  Here, the product substrate includes a substrate and one or more films formed on the substrate.

  According to the film thickness measurement apparatus of this embodiment, the measurement instrument calibration means adjusts the height of the measurement head by measuring the displacement sensor using the height adjustment unit of the gain calibration sample. Then, the gain of the measuring head is adjusted using the gain adjusting unit of the gain calibration sample. As a result, the height of the measuring head can be adjusted accurately, and the gain of the measuring head can be adjusted accurately.

In the gain calibration method of one embodiment,
A step of moving a displacement sensor for measuring the distance from the formed product substrate and a measurement head for measuring the thickness of the film of the product substrate to a calibration stage on which a gain calibration sample is placed When,
Adjusting the height of the measurement head by measuring the displacement sensor using the height calibration unit of the gain calibration sample; and
And a step of adjusting the gain of the measurement head using the gain adjustment unit of the gain calibration sample.

  Here, the product substrate includes a substrate and one or more films formed on the substrate.

  According to the gain calibration method of this embodiment, the height of the measurement head is adjusted by measurement of the displacement sensor using the height adjustment unit of the gain calibration sample, and then the gain of the gain calibration sample is adjusted. The gain of the measurement head is adjusted using the adjustment unit. As a result, the height of the measuring head can be adjusted accurately, and the gain of the measuring head can be adjusted accurately.

  According to the gain calibration sample of the present invention, since the height adjustment unit and the gain adjustment unit are provided, the height of the measurement head can be adjusted accurately.

  According to the film thickness measuring apparatus of the present invention, the measuring instrument calibration means adjusts the height of the measuring head by measuring the displacement sensor using the height adjusting unit of the gain calibration sample, The gain of the measurement head is adjusted using the gain adjustment unit of the gain calibration sample. As a result, the height of the measuring head can be adjusted accurately, and the gain of the measuring head can be adjusted accurately.

  According to the gain calibration method of the present invention, the height adjustment unit of the gain calibration sample is used to adjust the height of the measurement head by measuring the displacement sensor, and then the gain adjustment of the gain calibration sample is performed. Is used to adjust the gain of the measuring head. As a result, the height of the measuring head can be adjusted accurately, and the gain of the measuring head can be adjusted accurately.

It is a top view which shows the film thickness measuring apparatus of one Embodiment of this invention. It is a side view of the film thickness measuring apparatus seen from the arrow U direction of FIG. It is explanatory drawing explaining operation | movement of a displacement sensor. It is explanatory drawing explaining operation | movement of a measurement head. It is explanatory drawing explaining the state which a fluorescent X ray generate | occur | produces by irradiation of a primary X ray. It is a table | surface which shows the relationship between the X-ray intensity and film thickness in a titanium film and a molybdenum film | membrane. It is the graph which plotted the data of FIG. 6A. It is a top view which shows the gain calibration sample of one Embodiment of this invention. It is sectional drawing which shows the gain calibration sample of one Embodiment of this invention. It is explanatory drawing explaining the method to adjust the height of a measurement head by the measurement of a displacement sensor. It is explanatory drawing explaining the method to adjust the gain of a measurement head. It is explanatory drawing explaining the method of adjusting the conventional gain.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

  FIG. 1 is a plan view showing a film thickness measuring apparatus according to an embodiment of the present invention. FIG. 2 is a side view seen from the direction of arrow U in FIG. As shown in FIGS. 1 and 2, the film thickness measuring apparatus includes a base 1, a substrate stage 2, a calibration stage 3, a gantry 4, a slider 5, and a plurality of measuring devices 21, 22, and 23. And control means 30.

  The substrate stage 2 includes a stage provided on the base 1 and divided into a plurality of stages. On the substrate stage 2, the formed product substrate 10 is placed.

  The substrate stage 2 is provided with a plurality of air holes 2a. By sucking air from the air holes 2a, the product substrate 10 can be brought into close contact with the substrate stage 2, while air is blown out from the air holes 2a. The product substrate 10 can be lifted from the substrate stage 2.

  The product substrate 10 is, for example, a liquid crystal TFT used for a liquid crystal display. The product substrate 10 includes a substrate and one or more films formed on the substrate. The film is formed on the substrate by, for example, a sputtering method, a vapor deposition method, or a plating method. The substrate is, for example, a glass substrate, and the film is a metal film such as aluminum, titanium, tungsten, or molybdenum.

  The calibration stage 3 is provided on the base 1 and is provided separately from the substrate stage 2. The calibration stage 3 is provided with a plurality of recesses 3a, and various types of calibration samples 60 and 70 are fitted into the recesses 3a, and the calibration samples 60 and 70 are used for the measurement devices 21, 22, and 23. Calibration is performed.

  The gantry 4 extends in the first direction with respect to the substrate stage 2 and the calibration stage 3. The gantry 4 is attached to the base 1 so as to be movable in the second direction with respect to the substrate stage 2 and the calibration stage 3. The first direction refers to the direction of arrow A, and the second direction refers to the direction of arrow B. The first direction and the second direction are orthogonal to each other.

  That is, the base 1 is provided with two rail portions 6 and 6 extending in the second direction (arrow B direction). The two rail portions 6 and 6 are arranged so as to sandwich the substrate stage 2 and the calibration stage 3. The gandries 4 are stretched over the two rail portions 6 and 6 and can move along the rail portions 6 and 6 in the second direction.

  The slider 5 is attached to the gantry 4 so as to be movable in the first direction (arrow A direction). A camera 21, a displacement sensor 22, and a measurement head 23 as the measurement device are fixed to the slider 5.

  The measuring devices 21, 22, and 23 can cover the entire range of the substrate stage 2 and the calibration stage 3 in the second direction (arrow B direction) by the movable range Z1 of the gantry 4. Further, the measuring devices 21, 22, and 23 can cover the entire range of the substrate stage 2 and the calibration stage 3 in the first direction (arrow A direction) by the movable range Z <b> 2 of the slider 5.

  The control unit 30 includes a substrate position correction unit 31, a head position adjustment unit 32, an analysis unit 33, and a measurement device calibration unit 34.

  The camera 21 detects an alignment mark of the product substrate 10 placed on the substrate stage 2. This alignment mark is a mark that can be identified by the camera 21, and is provided at, for example, the four corners of the product substrate 10.

  The substrate position correcting unit 31 corrects position information in the planar direction (first and second directions) of the product substrate 10 placed on the substrate stage 2 based on the detection result of the camera 21. Specifically, the base 1 is provided with a plurality of clamps 7 so as to press each side around the product substrate 10. After fixing the product substrate 10 to a predetermined position by the clamp 7, the alignment mark is detected by the camera 21, and the position information of the product substrate 10 is corrected by the substrate position correcting means 31 based on the detection result.

  As shown in FIG. 3, the displacement sensor 22 measures a distance in the height direction from the product substrate 10 placed on the substrate stage 2. The displacement sensor 22 irradiates a predetermined measurement point P of the product substrate 10 with light rays such as infrared rays, detects the reflected light from the measurement point P, and measures the distance to the measurement point P.

  Based on the measurement value of the displacement sensor 22, the head position adjusting means 32 is configured so that the distance between the product substrate 10 placed on the substrate stage and the measurement head 23 becomes a predetermined set value. The position of the measuring head 23 in the height direction is adjusted. Specifically, the distance in the height direction between the measurement point P of the product substrate 10 and the light emitting / receiving unit 23a of the measurement head 23 is adjusted to be 2 mm ± 30 μm.

  The head position adjusting means 32 adjusts the position of the measurement head 23 in the height direction, and then moves the measurement head 23 to a position where the measurement head 23 can measure the measurement point P of the product substrate 10.

  As shown in FIG. 4, the measurement head 23 includes an X-ray irradiation unit 231 and a fluorescent X-ray detection unit 232.

  The X-ray irradiation unit 231 irradiates the measurement point P of the product substrate 10 with the primary X-ray 51 from the light emitting / receiving unit 23a. The primary X-ray 51 is, for example, rhodium, molybdenum, tungsten, or the like. Then, as shown in FIG. 5, the film 12 on the substrate 11 of the product substrate 10 generates fluorescent X-rays 52 by irradiation with the primary X-rays 51.

  The fluorescent X-ray detection unit 232 detects the fluorescent X-ray 52 generated from the film 12 from the light emitting / receiving unit 23a. The fluorescent X-ray detector 232 is, for example, a silicon drift detector.

  The analyzing means 33 obtains the thickness of the film 12 from the intensity of the fluorescent X-ray 52 detected by the measuring head 23. Specifically, the analysis means 33 includes a preamplifier 331 and a multi-channel analyzer (hereinafter referred to as MCA) 332.

  The preamplifier 331 amplifies the electric signal output from the fluorescent X-ray detection unit 232. The MCA 332 analyzes the electrical signal amplified by the preamplifier 331. In the MCA 332, the energy output from the fluorescent X-ray detection unit 232 is selected, and the pulse is measured to obtain the X-ray intensity of the elements constituting the film 12. And based on this X-ray intensity, the thickness of the film | membrane 12 is calculated | required from known data. Note that since the MCA 332 is used, foreign matters and impurities mixed in the film 12 can be detected.

  For example, when the film 12 is a titanium film or a molybdenum film, the relationship between the X-ray intensity and the film thickness is as shown in FIGS. 6A and 6B.

  In the above description, the measurement of the thickness of the single-layer film (FIG. 5) has been described. However, the thickness of the multi-layer film can also be measured. In this case, fluorescent X-rays generated from each film are detected by the measuring head 23, and the X-ray intensity of each element constituting each film is obtained by the analyzing means 33, and the thickness of each film is determined based on this X-ray intensity. Ask for. Furthermore, the composition ratio of each element can also be obtained from the X-ray intensity of each element.

  As shown in FIG. 1, the measuring instrument calibration means 34 moves the measuring instruments 21, 22, 23 to the calibration stage 3 to calibrate the measuring instruments 21, 22, 23. Calibration of the measuring devices 21, 22, and 23 is performed at predetermined intervals. The predetermined interval is, for example, every predetermined time such as performing calibration once a day, or every predetermined number of processes such as performing calibration after measuring the film thickness of a predetermined number of product substrates 10.

  On the calibration stage 3, a gain calibration sample 60 and an offset amount calibration sample 70 are installed. The gain calibration sample 60 is a sample for adjusting the gain of the fluorescent X-ray detection unit 232 of the measurement head 23. The offset amount calibration sample 70 is a sample for adjusting the offset amount of each measuring device 21, 22, 23.

  The gain calibration sample 60 includes a height adjusting unit 61 and a gain adjusting unit 62 as shown in FIGS. 7A and 7B. The height adjusting unit 61 is a part for adjusting the height of the measuring head 23 by the measurement of the displacement sensor 22. The gain adjusting unit 62 is a part for adjusting the gain of the measuring head 23.

  The height adjusting portion 61 is formed in a rectangular parallelepiped shape, and a cylindrical recess 61a is provided on the upper surface. The gain adjusting unit 62 is fitted into the recess 61a. The height adjustment unit 61 is made of a material that substantially totally reflects the light beam of the displacement sensor 22. The height adjusting unit 61 is made of a metal such as stainless steel or aluminum.

  The gain adjusting unit 62 includes a sample material 621 and a glass 622 that covers the sample material 621. The sample material 621 generates fluorescent X-rays when irradiated with primary X-rays from the measurement head 23. Since the characteristics of the sample material 621 are known, the gain of the measuring head 23 can be adjusted based on the sample material 621. The glass 622 protects the sample material 621. The gain adjustment unit 62 is formed in a columnar shape, and the upper surface of the glass 622 and the upper surface of the height adjustment unit 61 are at the same height in a state where the gain adjustment unit 62 is fitted in the recess 61 a of the height adjustment unit 61.

  A method for adjusting the gain of the measurement head 23 using the gain calibration sample 60 will be described.

  First, the position of the measurement head 23 in the height direction is adjusted so that the distance between the measurement head 23 and the gain calibration sample 60 becomes a predetermined set value. At this time, as shown in FIG. 8A, the distance between the gain calibration sample 60 and the height adjusting unit 61 is measured by the displacement sensor 22, and the height of the measuring head 23 is measured based on the measured value. Adjust the position.

  Thereafter, as shown in FIG. 8B, the measurement head 23 is moved to a position facing the gain adjustment unit 62 of the gain calibration sample 60, and the gain of the measurement head 23 is adjusted using the gain adjustment unit 62. .

  Next, the operation of the film thickness measuring apparatus having the above configuration will be described.

  As shown in FIG. 1, first, the product substrate 10 is transferred onto the substrate stage 2 from the right direction (arrow R direction) of the film thickness measuring device. The product substrate 10 transported onto the substrate stage 2 is fixed at a predetermined position by the clamp 7. Thereafter, the alignment mark is detected by the camera 21, and the position information of the product substrate 10 is corrected by the substrate position correcting unit 31 based on the detection result.

  Then, the distance in the height direction between the first measurement point and the displacement sensor 22 is measured by the displacement sensor 22 at the first measurement point among the plurality of measurement points of the product substrate 10. The head position adjusting means 32 adjusts the position of the measuring head 23 in the height direction so that the distance between the first measuring point and the measuring head 23 becomes a set value based on the measured value. To do.

  Thereafter, the measurement head 23 is moved directly above the first measurement point by the head position adjusting means 32, and the film of the product substrate 10 is irradiated with primary X-rays to detect fluorescent X-rays generated from this film. To do. Then, the analysis means 33 obtains the thickness of the film from the detected intensity of the fluorescent X-ray.

  Thereafter, with respect to the other measurement points of the product substrate 10, similarly, after adjusting the height of the measurement head 23, the film thickness of the other measurement points is measured by the measurement head 23.

  In this way, the film thicknesses of all measurement points of the product substrate 10 are measured, and based on the measurement result, it is determined whether or not the product substrate 10 is defective.

  Thereafter, the measuring instrument calibration means 34 moves the measuring instruments 21, 22, 23 to the calibration stage 3 at predetermined intervals, and calibrates the measuring instruments 21, 22, 23 using the calibration samples 60, 70. .

  According to the gain calibration sample 60 having the above configuration, since the height adjusting unit 61 and the gain adjusting unit 62 are provided, the adjustment of the height of the measurement head 23 is performed at a portion different from the adjustment of the gain of the measurement head 23. ,It can be carried out. Thereby, the height of the measuring head 23 can be adjusted accurately.

  According to the film thickness measuring apparatus having the above configuration, the measuring instrument calibration means adjusts the height of the measuring head 23 by the measurement of the displacement sensor 22 using the height adjusting unit 61 of the gain calibration sample 60. Then, the gain of the measuring head 23 is adjusted using the gain adjusting unit 62 of the gain calibration sample 60. As a result, the height of the measurement head 23 can be adjusted accurately, and the gain of the measurement head 23 can be adjusted accurately.

  According to the gain calibration method of the above configuration, the height calibration unit 61 of the gain calibration sample 60 is used to adjust the height of the measurement head 23 by measurement of the displacement sensor 22, and then the gain calibration sample. The gain of the measuring head 23 is adjusted using the 60 gain adjusting unit 62. As a result, the height of the measurement head 23 can be adjusted accurately, and the gain of the measurement head 23 can be adjusted accurately.

  In addition, since the film thickness is obtained by fluorescent X-ray analysis, a minute region of the film 12 of the product substrate 10 can be measured, and the film thickness measurement accuracy can be improved. Further, in the fluorescent X-ray analysis method, the film thickness measurement time can be shortened as compared with the X-ray reflectance method.

  Further, since the measurement head 23 is movable in the first direction and the second direction with respect to the substrate stage 2, the film thickness at a plurality of locations on the product substrate 10 can be measured with the measurement head 23. Thereby, it becomes suitable for the film thickness measurement of the large-sized product substrate 10.

  In addition, this invention is not limited to the above-mentioned embodiment. For example, the height adjustment unit 61 is the entire portion other than the gain adjustment unit 62 of the gain calibration sample 60, but may be the upper surface portion of the gain calibration sample 60 other than the gain adjustment unit 62.

  Further, the first direction that is the extending direction of the gantry 4 and the second direction that is the moving direction of the gantry 4 may cross each other without being orthogonal to each other.

  Further, the number of the camera 21, the displacement sensor 22, and the measuring head 23 is not limited to one and may be plural. Further, the camera 21 may be omitted.

  In addition, although two calibration samples 60 and 70 are installed on the calibration stage 3, the number of calibration samples can be freely increased or decreased. Also, other types of calibration samples may be used, for example, calibration samples for calibrating X-ray intensity drift.

  In addition, the film thickness measuring device of the present invention may be used to measure the film thickness of a small product substrate. In addition to the liquid crystal TFT, the film thickness of a semiconductor substrate such as an organic EL may be measured. Also good.

DESCRIPTION OF SYMBOLS 1 Base 2 Substrate stage 3 Calibration stage 4 Gantry 5 Slider 6 Rail part 7 Clamp 10 Product substrate 21 Camera 22 Displacement sensor 23 Measuring head 30 Control means 31 Substrate position correcting means 32 Head position adjusting means 33 Analyzing means 34 Measuring equipment calibration means 60 Gain calibration sample 61 Height adjustment unit 62 Gain adjustment unit 621 Sample material 622 Glass 70 Offset amount calibration sample A 1st direction B 2nd direction

Claims (3)

A calibration sample used for calibration of a film thickness measuring device having a displacement sensor for measuring a distance from a formed product substrate and a measurement head for measuring the thickness of the film of the product substrate,
A height adjusting unit for adjusting the height of the measuring head by measurement of the displacement sensor;
A gain calibration sample comprising: a gain adjusting unit for adjusting the gain of the measuring head. The base,
A substrate stage that is provided on the base and on which the formed product substrate is placed;
A calibration stage provided on the base and on which the gain calibration sample according to claim 1 is placed;
A gantry that extends in a first direction with respect to the substrate stage and the calibration stage and is attached to the base so as to be movable in a second direction with respect to the substrate stage and the calibration stage;
A slider attached to the gantry movably in the first direction;
A displacement sensor that is fixed to the slider and measures a distance from the product substrate placed on the substrate stage;
A measuring head fixed to the slider and measuring the thickness of the film of the product substrate placed on the substrate stage;
The displacement sensor and the measurement head are moved to the calibration stage, the height adjustment unit of the gain calibration sample is used to adjust the height of the measurement head by measuring the displacement sensor, and then the gain calibration is performed. A film thickness measuring apparatus comprising: a measuring device calibration unit that adjusts the gain of the measuring head using the gain adjusting unit of the sample. A step of moving a displacement sensor for measuring the distance from the formed product substrate and a measurement head for measuring the thickness of the film of the product substrate to a calibration stage on which a gain calibration sample is placed When,
Adjusting the height of the measurement head by measuring the displacement sensor using the height calibration unit of the gain calibration sample; and
And a step of adjusting the gain of the measurement head using a gain adjustment unit of the gain calibration sample.

Images