JP2014020973A - Device and method for measuring flatness - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flatness measuring device and a flatness measuring method which allow for measuring flatness of a surface under measurement without being affected by errors associated with movement accuracy of optical means such as a laser displacement meter.SOLUTION: A measurement light beam is irradiated on a vertically placed glass substrate and on a vertically or approximately vertically placed object under measurement through the glass substrate, and a reflected measurement light beam from the object under measurement and a reflected light beam from the glass substrate are measured. The measurement light beam is irradiated on a plurality of spots on the object under measurement and a plurality of reflected measurement light beams and reflected light beams from the glass substrate are acquired to measure flatness of the object under measurement using the plurality of reflected measurement light beams, the plurality of reflected light beams from the glass substrate, and flatness of the glass substrate surface.

Description

  The present invention relates to a flatness measuring apparatus and method, and more particularly to a flatness measuring apparatus and method for measuring the flatness of a holding table for holding a substrate.

  Flat panel displays using liquid crystal, etc., have become a mainstream display means for TVs, and have become indispensable as a display device for portable terminals by destroying the cathode ray tube due to features such as light weight, thinness, and low power consumption. ing. Such a flat panel display is manufactured by forming a display element on a substrate such as glass, but a manufacturing apparatus capable of forming the element on a larger substrate is demanded in order to increase the screen size and reduce the manufacturing cost. .

  Since such a substrate is thin compared to its size, when forming an element, it is not possible to maintain its shape simply by supporting the substrate from the outside, but on a holding table that is the same size or larger than the substrate. A substrate is placed. In this case, the substrate is placed so as to follow the surface shape of the holding table depending on the weight of the substrate. That is, the surface accuracy (flatness) of the holding table affects the flatness of the substrate. On the other hand, particularly in a portable terminal, the size of a pixel is reduced for higher definition. Therefore, if the flatness of a substrate at the time of film formation is poor, a defect may occur in the pixel.

  For this reason, it is important to periodically check the flatness of the holding table. Patent Document 1 describes a technique of measuring using a laser displacement meter when measuring the flatness of a substrate. In particular, it is disclosed to measure the distance between a reference plane having high flatness and the front and back surfaces of a substrate with a laser displacement meter.

JP 2007-46946 A

  When measuring flatness using a laser displacement meter, the laser displacement meter is run in parallel with the substrate to be measured and a holding table, and the distance between the laser displacement meter and the substrate surface to be measured is measured. On the other hand, the substrate is becoming larger and the moving distance of the laser displacement meter must be increased accordingly.

  Due to the increase of the moving distance, the traveling error of the laser displacement meter also increases, and this moving error is included in the measured value of the flatness of the measurement object, and an accurate measurement result cannot be obtained. For this reason, it is necessary to reduce the error by making the movement accuracy of the laser displacement meter high.

  However, in order to move the laser displacement meter with high accuracy, a high-accuracy and high-rigidity moving mechanism is required, and this type of moving mechanism is expected to be large and heavy and difficult to handle. .

  Further, in the method of Patent Document 1, a reference plane having a highly accurate planar shape with a surface roughness of 400 nm or less is required, but such a highly accurate reference plane is expensive.

A first object of the present invention is to provide a flatness measuring apparatus and method for measuring the flatness of a surface to be measured such as a substrate, which does not depend on the movement accuracy of an optical means such as a laser displacement meter.
The second object of the present invention is to measure the flatness of an organic EL film forming apparatus capable of measuring the flatness of the surface of the substrate holder that holds the substrate without depending on the movement accuracy of optical means such as a laser displacement meter. It is to provide an apparatus and a method thereof.

The present invention has at least the following features in order to achieve the above-mentioned goal.
The present invention relates to an object to be measured that is held vertically or substantially vertically, a glass substrate that is held by a first holding means and is provided in parallel with the object to be measured, and is transmitted through the glass substrate. Then, an irradiating means for irradiating the measurement target with measurement light, a first measurement means for measuring the measurement reflected light from the measurement target, and a second for measuring the glass substrate reflected light from the glass substrate Measuring means, and the irradiation means, the first measuring means, and the measurement means so that the measurement light can be irradiated to a predetermined position of the measurement target, and the measurement reflected light and the glass substrate reflected light can be measured. A two-dimensional movement mechanism for moving the second measuring means; and the two-dimensional movement mechanism for controlling the surface of the object to be measured from the measurement result of the measurement reflected light and the reflected light of the glass substrate and the flatness of the glass substrate. Control device for measuring the flatness of , The first, comprising a.

  Further, the present invention irradiates measurement light to a glass substrate provided vertically and an object to be measured that is transmitted through the glass substrate and held vertically or substantially perpendicular to the glass substrate, The measurement reflected light from the object and the glass substrate reflected light from the glass substrate are measured, the measurement light is irradiated to a plurality of positions of the measurement target, and the plurality of measurement reflected light and the glass substrate reflected light are irradiated. The second characteristic is that the flatness of the surface to be measured is measured from a plurality of the measured reflected light, the reflected glass substrate light, and the flatness of the glass substrate surface.

  Further, the object to be measured is a substrate holder for holding the substrate in a vacuum deposition chamber for depositing a deposition material on the substrate, and the first holding means is a mask for depositing a predetermined position on the substrate. The two-dimensional movement mechanism may be fixed to the simulated mask.

The base and the object to be measured are held by second holding means provided on the base, the first holding means is provided on the base, and the two-dimensional moving mechanism is You may provide in a 1st holding means or the said base.
Furthermore, the irradiation unit, the first measurement unit, and the second measurement unit may be a laser displacement meter in which they are integrated.
The flatness of the glass substrate may be known.

Further, the second measuring means measures the glass substrate surface reflected light and the glass substrate back surface reflected light from the surface on the second measuring means side of the glass substrate and the back surface on the opposite side, and the control device The flatness of the glass substrate surface may be obtained based on the glass substrate surface reflected light and the glass substrate back surface reflected light.
The flatness of the glass substrate may be obtained based on a difference in measurement distance between the reflected light on the glass substrate surface and the reflected light on the back surface of the glass substrate.

ADVANTAGE OF THE INVENTION According to this invention, the flatness measuring apparatus and its method which can measure the flatness of the to-be-measured object surfaces, such as a board | substrate, which do not depend on the movement precision of optical means, such as a laser displacement meter, can be provided.
Further, according to the present invention, in the organic EL film forming apparatus, the flatness measuring device capable of measuring the flatness of the surface of the substrate holding table that holds the substrate, which is independent of the movement accuracy of the optical means such as a laser displacement meter, and the same Can provide a method.

It is a figure which shows embodiment of the organic EL device manufacturing apparatus to which this invention is applied. It is a figure which shows the structure outline | summary of the vacuum conveyance chamber and the vacuum evaporation chamber in the organic EL device manufacturing apparatus of this embodiment. It is the figure which showed the structure of a mask, and the relationship between a board | substrate holding part and a mask. It is a figure which shows the 1st Example of a flatness measuring device. It is a figure which shows the relationship of the main elements for calculating | requiring flatness, and the data measured with the laser displacement meter at that time. It is a figure which shows the flatness measurement processing flow of a substrate holding stand surface. It is a figure which shows the 2nd Example of a flatness measuring device. It is a figure which shows embodiment using a flatness measuring apparatus as stand-alone.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows an embodiment of an organic EL device manufacturing apparatus to which an embodiment of the present invention is applied, and further shows an organic EL device manufacturing apparatus 100 that realizes alignment and vapor deposition in the same vacuum vapor deposition chamber 1. The organic EL device manufacturing apparatus 100 is a cluster in which a polygonal vacuum transfer chamber 2 having a vacuum transfer robot 5 at the center and a substrate stocker chamber 3 and a vacuum deposition chamber 1 as a film forming chamber are arranged radially around the periphery. Type organic EL device manufacturing apparatus. Each vacuum deposition chamber 1 includes a substrate holding unit 9 that holds a substrate 6, an alignment unit 8, and a vapor deposition unit 7 that deposits a vapor deposition material on the substrate. Further, a gate valve 10 that isolates the vacuum from each other is provided between the vacuum deposition chamber 1 and the substrate stocker chamber 3 and the vacuum transfer chamber 2. Reference numeral 40 denotes a control device that controls components of the organic EL device manufacturing apparatus 100.

FIG. 2 shows a schematic configuration of the vacuum transfer chamber 2 and the vacuum deposition chamber 1 in the organic EL device manufacturing apparatus of this embodiment.
The vacuum transfer chamber 2 includes a vacuum transfer robot 5 that carries the substrate 6 into and out of the vacuum deposition chamber 1 via the gate valve 10. The vacuum transfer robot 5 has a degree of freedom 59 that can move up and down as a whole, a two-link structure arm 57 that can turn left and right, and a comb-like hand 58 for transferring a substrate at the tip.

  On the other hand, the vacuum deposition chamber is a vacuum chamber in which a light emitting material as a deposition material is deposited on the substrate 6 to form an EL layer. The substrate holding unit 9 of the vacuum evaporation chamber 1 can deliver the substrate 6 without interfering with the comb-like hand 58 of the transfer robot 5 and holds the substrate 6 carried in via the gate valve 10. 91, and substrate holding table turning means 93 for turning the substrate holding table 91 so that the substrate 6 stands upright and faces the mask 81. The substrate holding base 91 has a cooling mechanism for cooling the substrate 6 and is also called a cooling plate.

  The alignment unit 8 includes a mask 81, an alignment driving unit 83 that moves the mask 81 up and down, left and right, and an alignment camera 86 that captures an alignment mark (not shown) provided on each of the mask 81 and the substrate 6. .

  As shown in FIG. 3, the mask 81 includes a mask portion 81M that forms a vapor deposition pattern on the substrate 6 and a frame portion 81F that holds the mask portion. As shown in the drawing, the mask portion 81M has an opening 81h at a location corresponding to a portion to be deposited on the substrate 6. In this example, an opening corresponding to red is shown in a mask for depositing red (R), green (G), and blue (B) light emitting materials. That is, in the case of a mask for red (R), only red (R) is opened as shown in the second and third stages of the drawing. The size of the mask becomes 2000 mm × 2000 mm with the increase in size of the substrate, and its weight also exceeds 300 kg. The thickness of the mask portion 81M is about 50 μm and tends to become thinner in the future. On the other hand, the thickness of the frame portion 81F is 50 mm.

  The alignment driving unit 83 is driven by the control device 40 based on the imaging result of the alignment camera 86, and aligns the mask 81 and the substrate 6 in a vertical state. The mask 81 is held at a lower portion thereof so as not to have a degree of freedom in a direction other than the direction in which the alignment driving unit 83 is driven vertically and horizontally, that is, in the front-rear direction. The vapor deposition unit 7 includes an evaporation source 71 and an evaporation source lifting / lowering means 72 that lifts and lowers the evaporation source, and deposits the entire surface of the substrate 6.

  FIG. 4 is a diagram showing the relationship between the substrate holding part 91 and the mask 81. The mask 81 is held vertically, and the substrate holding portion 91 faces the mask 81 with an inclination of up to about 1 degree in the vertical direction or the direction opposite to the mask side.

  A feature of this embodiment is that a glass substrate with a known flatness is fixed to a simulated mask 81s having only a frame portion 81F that does not have a mask portion 81M, and the substrate holding surface 91h of the substrate holding portion 91 is fixed by a laser displacement meter. It is to measure the flatness.

  FIG. 4 is a diagram illustrating a first embodiment of the flatness measuring apparatus 20. FIG. 4A is a side view of the flatness measuring apparatus 20 as viewed from the direction A in FIG. FIG. 4B is a front view of the flatness measuring device 20 as viewed from the B direction in FIG. 3, that is, from the vapor deposition section 7 side in FIG.

  The flatness measuring device 20 is provided on the opposite side of the simulated mask 81s having only the frame portion 81F, the known flat glass substrate 6g fixed to the simulated mask, and the substrate holding table 91 to be measured. The laser displacement meter 21 which is an optical means by integrating the means and the light receiving means, and the two-dimensional movement mechanism 22 which is fixed to the simulation mask 81s and moves the laser displacement meter in a plane parallel to the substrate holding surface 91h. In the embodiment, in the two dimensions, the vertical direction on the paper surface shown in FIG. By using the simulated mask 81s for fixing the glass substrate 6g, there is an advantage that the alignment unit 8 can be used as a holding unit for the glass substrate 6g without newly providing a mechanism.

  The two-dimensional moving mechanism 22 includes an outer frame 23 having an opening 23k larger than the opening 81k into which the glass substrate 6g of the simulated mask 81s is inserted, a Y moving mechanism 24 that moves the laser displacement meter 21 in the Y direction, The X direction mechanism 25 is provided above and below the outer frame 23 and moves the Y moving mechanism 24 in the X direction, and the fixing portions 26 are provided at the four corners that fix the outer frame 23 to the simulation mask 81s.

  The X moving mechanism 25 has two sets of linear guides LG provided on the upper and lower outer frames 23. The linear guide LG includes a guide rail 25r and a guide block 25g that moves on the guide rail. On the other hand, the Y moving mechanism 24 fixes the beam 24b fixed to the linear guide 25g of the X moving mechanism 25, the guide rail 24r provided on the beam 24b, and the laser displacement meter 21, and moves on the guide rail 24r. And a linear block 24g.

In the above description, the driving method of the linear blocks 24g and 25g is not shown, but a so-called linear motor, a ball screw driving by a rotary motor, or the like may be used.
According to the first embodiment, by integrating the glass substrate 6g, the simulated mask 81s, and the two-dimensional movement mechanism, it is possible to eliminate troublesome work when removing the apparatus from the apparatus during maintenance.
Next, a method for measuring the flatness of the surface of the substrate holding table 91, that is, the substrate holding surface 91h in this embodiment will be described.

FIG. 5 shows the relationship between the main elements for obtaining the flatness and the data measured by the laser displacement meter 21 at that time. Data to be measured are reflected light 21g from the front surface (or back surface) of the glass substrate 6g with respect to the pulsed light of the laser displacement meter 21, and reflected light 21t from the substrate holding surface 91h as a target. The control device 40 can determine the reciprocal distances Lg and Lt from the arrival times of the reflected lights 21g and 21t, respectively. The flatness measurement distance Ls between the glass substrate Lg and the substrate holding surface 91h can be obtained by Expression (1).
Ls = (Lt−Lg) / 2 (1)
As can be seen from the equation (1) and FIG. 5, the distance between the glass substrate 6g and the laser displacement meter 21 is irrelevant. Therefore, the two-dimensional movement mechanism 22 does not require the movement accuracy for moving the laser displacement meter to the plane parallel to the substrate holding surface 91h.

  According to the embodiment described above, by providing the glass substrate between the object to be measured and the laser displacement meter, the absolute distance from the laser displacement meter to the surface to be measured is not the distance between the glass substrate and the surface to be measured. By measuring the relative distance, the flatness of the surface to be measured can be measured regardless of the positional accuracy of the two-dimensional movement mechanism 22.

Further, since the positional relationship between the glass substrate 6g and the substrate holding portion 91 does not change during the measurement, the flatness measurement distance Ls can be measured at many points of the substrate holding portion 91, and the flatness can be evaluated by statistical processing. .
The flatness Hs of the substrate holding portion 91 is obtained as a difference between the measured flatness Hk obtained by statistically processing the flatness measurement distance Ls and the known flatness Hg of the glass substrate 6g subjected to the same statistical processing as shown in the equation (2). Desired.
Hs = Hk−Hg (2)
Note that, as the statistical processing described above, a difference between the maximum value and the minimum value, an average value, and the like are raised.

  According to the flatness measuring method described above, if the flatness Hg of the glass substrate 6g is obtained in advance, the flatness of the substrate holding surface 91h can be obtained. As for the flatness of the glass substrate 6g, a known flatness is obtained by a conventional technical method, particularly in a state where the glass substrate 6g is set in the simulated mass 81s.

Next, the flatness measurement process flow of the substrate holding part 91 including the above-described measurement method will be described with reference to FIG. The processing flow is performed by the control device 40 shown in FIG. The control device 40 controls the X moving mechanism 25 and the Y moving mechanism 24, takes in the output of the laser displacement meter 21, and performs data processing to obtain flatness.
First, as a preparation, the flatness of the glass substrate 6g is measured with another measuring device (S1). The simulated mask 81s in which the two-dimensional moving mechanism 22 is set, that is, the flatness measuring device 20 is set in the alignment unit 8 (S2). The laser displacement meter 21 is moved to the measurement position, and the flatness measurement distance Ls is measured (S3). It is determined whether the measurement of S3 has been performed at all predetermined positions (S4). If not, the laser displacement meter 21 is moved to the next measurement position (S5), and the process goes to S3. If implemented, statistical processing of the flatness measurement distance Ls is performed to evaluate the measurement flatness Hk (S6). Next, the flatness of the substrate holding surface 91h of the substrate holding base 91 is obtained from the known flatness Hg of the glass substrate 6g using Equation (2) (S7).

  According to the first embodiment described above, the flatness of the substrate holding surface 91h of the substrate holding table 91 can be measured with high accuracy, and the quality of vapor deposition caused by the surface accuracy (flatness) of the substrate holding surface 91h can be reduced. Can be prevented.

  FIG. 7 is a diagram showing a second embodiment of the flatness measuring apparatus 20. Example 2 is an example in which the front surface reflected light 21g and the back surface reflected light 21r can be discriminated and measured from the glass substrate 6g used for measurement.

  In Example 2, as in Example 1, the flatness Hg ′ including the front and back surfaces of the substrate 6g is evaluated from the front surface reflected light 21g and the back surface reflected light 21r. The flatness Hg is set to ½ of the flatness Hg ′ on each of the front and back surfaces. Next, the flatness Hs of the substrate holding surface 91 is obtained from the reflected light 21t and the front surface reflected light 21g or the back surface reflected light 21r from the substrate holding surface 91h.

  According to the second embodiment, it is possible to provide a method of measuring the flatness of the front and back surfaces of the glass substrate and determining the flatness Hs of the substrate holding surface 91 without measuring the flatness of the glass substrate 6g in advance.

  In the first and second embodiments described above, the substrate holding table 91 is vertically set by the substrate holding table turning means 93 shown in FIG. 1, and the substrate holding table faces the simulation mask 81s in parallel. Explained. However, as described in the description of FIG. In that case, for example, the angle detection device of the substrate holding table turning means 93 detects the inclination angle, corrects each flatness measurement distance Ls based on the inclination angle and the measurement position, and flatness of the substrate holding surface 91h. Can be measured.

  In the above description, the case of obtaining the flatness of the substrate holding surface 91h of the substrate holding table 91 of the organic EL film forming apparatus has been described. In the embodiment shown in FIG. 8, a holding unit 28 that holds a measurement target 30 such as a flatness measuring device 20 and a glass substrate and a base 27 that fixes the holding unit are provided and used as a stand-alone flatness measuring device. Can do. In this case, of course, the glass substrate holder 31 that holds the glass substrate 6g does not need to simulate the mask 81. Note that 30 h indicates the flatness measurement surface of the measurement object 30.

  In the above description, the irradiation unit for irradiating and the light receiving unit for receiving the reflected light using the laser displacement meter that can irradiate the measuring light and measure the reflected light may be provided separately and arranged in a V shape. .

1: Vacuum evaporation chamber 2: Vacuum transfer chamber 3: Substrate stocker chamber 5: Vacuum transfer robot 6: Substrate 6g: Glass substrate 7: Evaporation part 71: Evaporation source 8: Alignment part 81: Mask 81F: Mask frame part 81s: Simulated mask 9: Substrate holder 91: Substrate holder (cooling plate)
91h: Substrate holding surface of substrate holding part 10: Gate valve 20: Flatness measuring device 21: Laser displacement meter 22: Two-dimensional moving mechanism 23: Outer frame 24: Y moving mechanism 25: X moving mechanism 30: Measurement target
31: Glass substrate holding unit for holding the glass substrate 40: Control device 93: Substrate holding table turning driving means 100: Organic EL device manufacturing apparatus Hs: Flatness of substrate holding unit Hk: Measurement flatness flatness of substrate holding unit Hg : Known flatness of glass substrate Ls: Flatness measurement distance between glass substrate and substrate holding surface

Claims (12)

A measurement object held vertically or nearly vertically;
A glass substrate held by the first holding means and provided in parallel with the object to be measured;
Irradiating means for irradiating the object to be measured with measurement light through the glass substrate;
First measurement means for measuring measurement reflected light from the measurement object;
A second measuring means for measuring the glass substrate reflected light from the glass substrate;
The irradiation means, the first measurement means, and the second measurement are applied so that the measurement light is irradiated onto a predetermined position of the measurement target, and the measurement reflected light and the glass substrate reflected light can be measured. A two-dimensional movement mechanism for moving the means;
A control device for controlling the two-dimensional movement mechanism, and measuring the flatness of the measurement target surface from the measurement reflected light and the measurement result of the glass substrate reflected light and the flatness of the glass substrate;
A flatness measuring apparatus comprising: The object to be measured is a substrate holder that holds the substrate in a vacuum deposition chamber for depositing a deposition material on the substrate,
The first holding means is a simulated mask that simulates a frame portion of a mask for vapor deposition at a predetermined position on the substrate;
The flatness measurement apparatus according to claim 1, wherein the two-dimensional movement mechanism is fixed to the simulation mask. The base,
The measurement object is held by a second holding means provided on the base,
The first holding means is provided on the base;
The flatness measuring apparatus according to claim 1, wherein the two-dimensional movement mechanism is provided on the first holding unit or the base.   4. The flatness measuring apparatus according to claim 1, wherein the irradiation unit, the first measuring unit, and the second measuring unit are a laser displacement meter in which they are integrated. .   The said 1st measurement means and the said 2nd measurement means are arrange | positioned in the V shape with respect to the said irradiation means so that a measurement reflected light and a glass substrate reflected light can be measured, respectively. The flatness measuring apparatus according to 1, 2 or 3.   The flatness measuring apparatus according to claim 1, wherein the flatness of the glass substrate is known. The second measuring means measures the glass substrate surface reflected light and the glass substrate back surface reflected light from the surface on the second measuring means side of the glass substrate and the back surface on the opposite side,
The flatness measuring device according to claim 1, wherein the control device obtains the flatness of the glass substrate surface based on the glass substrate surface reflected light and the glass substrate back surface reflected light. Irradiating measurement light to a vertically provided glass substrate and a measurement target that is transmitted through the glass substrate and faces the glass substrate and is held vertically or substantially vertically,
Measure the measurement reflected light from the object to be measured and the glass substrate reflected light from the glass substrate,
Irradiating the measurement light to a plurality of positions of the measurement target, obtaining a plurality of the measurement reflected light and the glass substrate reflected light,
Measuring the flatness of the surface to be measured from the plurality of measurement reflected light, the glass substrate reflected light and the flatness of the glass substrate surface;
The flatness measuring method characterized by the above-mentioned.   The flatness measurement method according to claim 8, wherein the irradiation, the measurement reflected light, and the glass substrate reflected light are measured by a laser displacement meter.   The flatness measurement method according to claim 8, wherein the flatness of the glass substrate is known. The glass substrate reflected light measures the glass substrate surface reflected light and the glass substrate back surface reflected light from the surface on the measurement side of the glass substrate and the back surface on the opposite side,
The flatness measurement method according to claim 8, wherein flatness of the glass substrate surface is obtained based on the glass substrate surface reflected light and the glass substrate back surface reflected light.   The flatness measurement method according to claim 8, wherein the flatness of the glass substrate is obtained based on a difference in measurement distance between the reflected light on the front surface of the glass substrate and the reflected light on the back surface of the glass substrate.

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