JP2013078808A - Polishing apparatus and polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent at least the generation of a crack from an end surface of a display panel during polishing, in a polishing machine using a planetary carrier such as a double-side simultaneous polishing machine.SOLUTION: The polishing apparatus includes: an upper surface plate; a lower surface plate disposed facing the upper surface plate and rotating in an opposite direction to the upper surface plate; a sun gear rotated by the same rotational shaft as the upper surface plate and the lower surface plate; an internal gear rotated by the same rotational shaft as the upper surface plate and the lower surface plate; and the planetary carrier 5 in which a holding hole that holds a workpiece is formed, and which revolves while rotating by the engagement of the sun gear and the internal gear via an external tooth. The holding hole 10 in the planetary carrier 5 is formed with a notch at a side 10a (10b) located at a side of the holding hole 10 that comes into contact with a side surface of the workpiece when the planetary carrier 5 rotates.

Description

  The present disclosure relates to a polishing apparatus and a polishing method for polishing, for example, a glass substrate having a planarized surface and a display substrate for a liquid crystal display.

  In recent years, high-function mobile phones (so-called smartphones) having functions of a personal portable computer in addition to a conventional mobile phone having only a call function have been spreading. A thin panel display (FPD) such as a liquid crystal panel or an organic EL (electroluminescence) panel is often used for the display unit of such a portable terminal device. A thin panel display, that is, a display panel, is polished on the front surface (and the back surface) before being attached to these portable terminal devices. For example, in a polishing process for a liquid crystal panel in which a color filter 15 and a TFT (Thin Film Transistor) substrate 16 are bonded as shown in FIG. Both the color filter 15 and the TFT substrate 16 are mainly glass substrates.

  Conventionally, a double-sided simultaneous polishing machine is known as a polishing machine for polishing a display panel. The double-sided simultaneous polishing machine makes a planetary movement of the planet carrier holding the object to be polished, and polishes the object to be polished held in the holding hole of the planet carrier between the upper surface plate and the lower surface plate. Can be processed simultaneously. During polishing, a slurry (abrasive) supplied from the upper surface plate is interposed between the upper surface plate and the lower surface plate, and the surface of the object to be polished is polished.

For example, as a technique for polishing an object to be polished, Patent Document 1 discloses an arbitrary position of a positioning hole in order to facilitate removal of the object to be polished when performing single-side polishing (single-sided bonding) of the object to be polished. Is provided with a notch.
Patent Document 2 describes a polishing apparatus that polishes an object to be polished by providing reliefs (injection holes 5) at four corners of a recess hole 2 formed in a substantially rectangular shape of the object holder.

JP-A-61-230866 JP 2001-198805 A

  By the way, when the cracking strength of the display panel polished by the double-sided simultaneous polishing machine is measured using a strength tester, two types of cracking modes are confirmed as shown in FIG. FIG. 12A shows a crack 21 starting from the end face, and FIG. 12B shows a crack 22 starting from the in-plane. Cracks starting from the end face remarkably occur in a strength test by the JIS method. In addition, cracks starting from the surface are conspicuously generated in the strength test by the DIG method.

  At present, the functionality of mobile terminal devices has been dramatically improved, and at the same time, the number of individuals who own and carry mobile terminal devices has increased. In accordance with such user trends, a display panel with higher cracking strength is desired.

The polishing machine described in Patent Document 1 does not improve the strength of the polished object after polishing, and does not contribute to improving the strength of the polished object.
Further, in the polishing apparatus described in Patent Document 2, the end surface (side surface) of the object to be polished and the side of the recess hole 2 of the object holder to be polished are in contact with each other over a long part including the center of the side. The strength of the polished product will be reduced.

  The present disclosure has been made in consideration of the above-described situation, and in a polishing apparatus using a planetary carrier such as a double-sided simultaneous polishing machine, at least a crack starting from the end face of the display panel at the time of polishing does not occur. Like that.

  One aspect of the present disclosure includes an upper surface plate, a lower surface plate that is disposed opposite to the upper surface plate and rotates in the opposite direction to the upper surface plate, and rotates on the same rotation axis as the upper surface plate and the lower surface plate. A sun gear, an internal gear that rotates on the same rotation axis as the upper and lower surface plates, and a holding hole that holds the object to be polished are formed. And a planet carrier. The holding hole of the planet carrier is provided with a notch on the side of the holding hole that comes into contact with the side of the object to be polished when the planet carrier rotates.

  According to one aspect of the present disclosure, by forming a notch, the contact between the side surface of the object being polished and the side of the holding hole of the planet carrier is avoided or the contact length (area) is reduced.

  According to one aspect of the present disclosure, it is possible to prevent a crack starting from an end surface of an object to be polished from occurring during polishing.

It is an external view for demonstrating the outline | summary of the grinding | polishing apparatus which concerns on 1st Embodiment of this indication. It is a perspective view with which it uses for description of the planet carrier of the grinding | polishing apparatus which concerns on 1st Embodiment of this indication. It is a top view showing an example of a planet carrier concerning a 1st embodiment of this indication. It is sectional drawing in the AA line of the holding hole escape part vicinity of a planetary carrier in the state by which the to-be-polished object is mounted | worn in the holding hole. It is explanatory drawing which shows the example of supply of the slurry with respect to a grinding | polishing apparatus. It is the schematic for demonstrating the operation example of a grinding | polishing apparatus. It is explanatory drawing which shows the measuring method of the intensity | strength of the to-be-polished object by a JIS system strength test. It is the graph which showed the example of a relationship between fracture strength and a cumulative defect rate. It is explanatory drawing which shows an example of the result analyzed by Taguchi method, A shows the result about S / N (stability), B shows the result about sensitivity (characteristic value). It is a graph which shows the improvement degree of the average intensity | strength of a to-be-polished object when grind | polishing on more suitable conditions. It is a perspective view which shows an example of a display panel. It is explanatory drawing which shows the kind of crack which arises in a display panel, A is a crack from which the end surface has originated, B is a crack from which the in-plane has originated.

  Exemplary embodiments for carrying out the present disclosure will be described below with reference to the accompanying drawings. In addition, in this specification and drawings, about the component which has the substantially same function or structure, the overlapping description is abbreviate | omitted by attaching | subjecting the same code | symbol.

The description will be made in the following order.
1. Introduction explanation2. First embodiment (planet carrier: an example in which a relief portion is provided in a holding hole)
3. Second Embodiment (Polishing condition: example in which control factors are appropriately set)

<1. Introduction explanation>
Among the two types of cracking modes described above, the inventors of the present invention are caused by the contact between the object to be polished and the planet carrier during polishing because the crack originated from the end face of the object to be polished (see FIG. 12A). Therefore, it was thought that cracks occurred on the side surface, leading to insufficient strength.
Therefore, the present inventors considered that it would be effective to prevent the contact between the side surface of the object to be polished and the planetary carrier as a measure for preventing cracks whose origin is the end surface of the object to be polished. This preventive measure is embodied as the first embodiment.

On the other hand, the inventors of the present invention found that the cause of cracks (see FIG. 12B) starting from the surface of the object to be polished was generated in the surface by polishing and grains because the polishing conditions were not optimized. It was thought that the strength was insufficient due to extremely fine cracks (microcracks).
Therefore, the inventors of the present invention have a technical idea that it is effective to optimize the polishing conditions (calculate the optimum value in the shortest time) as a measure for preventing cracks based on the in-plane of the workpiece. I thought. This preventive measure is embodied as the second embodiment.

<2. First Embodiment>
[Configuration example of polishing apparatus]
A polishing apparatus according to a first embodiment of the present disclosure will be described with reference to the drawings.
The first embodiment is an example in which the polishing apparatus according to the present disclosure is applied to a double-sided simultaneous polishing machine. First, the structure of a double-sided simultaneous polishing machine to which the polishing apparatus according to the present disclosure is applied will be described with reference to FIGS.

FIG. 1 is an external view for explaining an overview of a polishing apparatus according to a first embodiment of the present disclosure. In this figure, the description of the planet carrier is omitted.
FIG. 2 is a perspective view for explaining the planet carrier of the polishing apparatus according to the first embodiment of the present disclosure.
FIG. 3 is a plan view illustrating an example of a planet carrier according to the first embodiment of the present disclosure.

  As shown in FIGS. 1 and 2, the polishing apparatus of the present embodiment includes an upper surface plate 1, a lower surface plate 2 that is disposed to face the upper surface plate 1, a sun gear 3, and an internal gear 4. It has. These four gears (rotators) can be rotated independently by selecting the number of rotations.

  The upper surface plate 1 is an annular disk that holds the display panel of the object to be polished from the upper side, and rotates by receiving the rotational force of the upper surface plate rotation driving unit 1A. The lower surface plate 2 is an annular disk that rotates with an object to be polished, and rotates by receiving a rotational force from a lower surface plate receiver (not shown). The upper surface plate 1 and the lower surface plate 2 during polishing rotate in opposite directions. For example, when the polishing apparatus is viewed from above, when the rotation direction Du of the upper surface plate 1 is clockwise, the rotation direction Dl of the lower surface plate 2 is counterclockwise.

  The sun gear 3 is an external gear positioned at the center of the upper surface plate 1 and the lower surface plate 2, and uses a tooth profile of the same size as the tooth profile of the planetary carrier 5. It rotates on the same rotation axis as the upper surface plate 1 and the lower surface plate 2, and is also called a sun gear. On the other hand, the internal gear 4 is an internal gear positioned around the outer periphery of the lower surface plate 2 and uses a tooth profile having the same size as the tooth profile of the planet carrier 5. It rotates on the same rotation axis as the upper surface plate 1 and the lower surface plate 2.

  The planet carrier 5 disposed between the upper surface plate 1 and the lower surface plate 2 has a relatively thin disk shape, and teeth (concave grooves) are cut on the outer peripheral surface thereof, and the sun gear 3 and the internal gear. Revolves while engaging 4 and rotating. The rotation direction Ds of the sun gear 3 and the rotation direction Di of the internal gear 4 are the same, and the rotation direction of the planet carrier 5 is determined by the difference in the rotation speeds of the two gears. As a material of the planet carrier 5, a steel plate, a glass epoxy resin, a vinyl chloride plate or the like is used.

For example, when the sun gear 3 rotates faster than the internal gear 4 (counterclockwise), the planetary carrier 5 rotates in the clockwise direction Dc1. On the other hand, when the internal gear 4 rotates faster than the sun gear 3 (counterclockwise), the rotation direction of the planet carrier 5 is counterclockwise Dc2.
When the rotation of the lower surface plate 2 is counterclockwise Dl, the rotation of the planet carrier 5 is clockwise Dc1 is “forward rotation”. When the rotation of the lower surface plate 2 is counterclockwise Dl, the rotation of the planet carrier 5 is counterclockwise Dc2 is “reverse”.

  In addition, as shown in FIG. 3, the planet carrier 5 has a plurality of holding holes 10 into which the object to be polished is inserted in the plane portion. A display panel such as a liquid crystal panel cut out in a single piece is filled in the holding hole 10 of the planet carrier 5 and held during the polishing process.

  The holding hole 10 has a substantially rectangular shape, and its longitudinal direction is formed in parallel with the radial direction of the planet carrier 5. Then, substantially central portions (near the center) of two opposing longitudinal sides 10a and 10b constituting the holding hole 10 are cut out to form escape portions 11a and 11b. By thus forming notches in the holding hole 10, that is, by forming relief portions 11 a and 11 b, contact between the side surface of the object being polished and the longitudinal sides 10 a and 10 b of the holding hole 10 of the planet carrier 5 is avoided. Or, the contact length (area) decreases.

FIG. 4 is a cross-sectional view taken along the line AA in the vicinity of the relief portions 11 a and 11 b of the holding hole 10 in a state where the object to be polished is mounted in the holding hole 10.
As an example, when the rotation of the planet carrier 5 is reversed (counterclockwise Dc2), the object to be polished is caused to flow and be pressed against the side 10a side where the escape portion 11a of the holding hole 10 is formed by inertia. The side surface of the object to be polished receives a drag force F from the side 10a of the planet carrier 5 that abuts, which may cause cracks on the side surface of the object to be polished.

  In this example, as described above, by forming the relief portion, contact between the side surface of the object to be polished and the sides 10a and 10b of the holding hole 10 of the planet carrier 5 is avoided, or the contact length (area) is set. By reducing it, the generation of cracks can be suppressed as compared with the conventional case.

  In this example, the size of the holding hole 10 is slightly larger than the size into which the object to be polished enters. Thereby, the backlash is made between the holding hole 10 and the object to be polished, thereby reducing the chance that the side of the holding hole 10 is in contact with the object to be polished and further reducing the occurrence of cracks.

  In the example of FIG. 3, the cutout shape of the relief portions 11a and 11b is a semicircular or elliptical curved shape, but it may be a shape using three sides of a rectangle or two sides of a triangle.

  With such a configuration, the planet carrier 5 holding the object to be polished can be caused to perform planetary movement, the object to be polished can be polished between the upper surface plate 1 and the lower surface plate 2, and both surfaces of the object to be polished can be processed simultaneously. .

[Example of operation of polishing equipment]
The operation of the polishing apparatus having the above configuration will be described.
FIG. 5 is an explanatory diagram showing an example of supplying slurry to the polishing apparatus.
FIG. 6 is a schematic diagram for explaining an operation example of the polishing apparatus.

  In general, when the polishing process is started, the slurry (abrasive) 7 supplied as shown in FIG. 5 falls to the lower surface plate 2 side through holes formed in the upper surface plate 1. While the slurry 7 is interposed between the upper surface plate 1 and the lower surface plate 2, the slurry 7 is relatively moved while applying pressure P to the upper surface plate 1 or the lower surface plate 2 and the object to be polished (see FIG. 6). When contained in the slurry 7, the surface of the object to be polished is finished smoothly and with high precision by utilizing rolling, scratching, crushing, and the like of the grains.

[Strength test]
The strength test of the object to be polished after polishing is performed using a strength tester having the principle shown in FIG. The example of FIG. 7 shows the principle of the strength test of the JIS method. In the strength test of the JIS method, for example, a liquid crystal panel in which the color filter 15 and the TFT substrate 16 are bonded as a polishing object is placed horizontally on two rod-like tables 18A and 18B separated by 30 cm. Then, the object 17 having the protrusions is dropped from above along a prescribed method, and the occurrence of cracks and the state of cracks are observed. Further, a DIG method strength test (not shown) is also performed in conjunction with the JIS method to measure the strength of the polished object after polishing.
Note that 11N is required as the current target strength of the display panel.

FIG. 8 is a graph showing the measurement results of the strength test (in this example, JIS method) of the liquid crystal panel (FIG. 11) when the escape portions 11 a and 11 b are provided in the holding holes 10 of the planet carrier 5. The graph of FIG. 9 shows an example of the relationship between the fracture strength (N) and the cumulative failure rate F (t) (%), which is a so-called Weibull distribution.
Initially, when a strength test is performed on 1000 liquid crystal panels with respect to the strength before the relief portions 11a and 11b are provided, it is indicated that there is a liquid crystal panel having a breaking strength of 8N and insufficient strength. On the other hand, by using the planetary carrier 5 provided with the escape portions 11a and 11b, it was possible to secure a breaking strength of 25N and a strength three times or more. This satisfies 11N, which is the current target strength of the display panel.

  According to the first embodiment described above, a significant improvement in strength can be ensured by providing the escape portion (notch) in the holding portion of the object to be polished of the planet carrier. As an example, a three-fold improvement in strength was observed on the Weibull distribution.

<3. Second Embodiment>
A second embodiment of the present disclosure will be described with reference to Table 1 and FIG.
As shown in Table 1, eight items were listed as polishing control factors, and three levels were set for each item. In the table, “specific gravity”, “particle size”, “flow rate”, and “slurry temperature” are items for the slurry. “Rise 4 steps” indicates the time required for each gear to increase its rotational speed to a specified speed in four stages. “Forward / Reverse” indicates the direction of rotation of the planet carrier 5. The pressing pressure is a pressure for pressing the upper surface plate 1 (or the lower surface plate 2) against the object to be polished. In addition, when the rotation speed of the lower surface plate 2 is 30 rpm, 35 rpm, and 40 rpm, as an example, the rotation speed of the upper surface plate 1 is 10.2 rpm, 11.9 rpm, and 13.6 rpm, respectively.

FIG. 9 shows the result of analysis using Taguchi method for levels 1 to 3. Note that the conditions of levels 1 to 3 for each item in Table 1 and the level conditions corresponding to each item shown in FIG.
The graph of FIG. 9A shows the stability (S / N ratio) related to strength when an object to be polished is produced as a product. On the other hand, the graph of FIG. 9B shows the intensity (sensitivity (characteristic value)) of each item of the control factor. The direction of Good indicates high stability and high strength (sensitivity).

As shown in the columnar graph of FIG. 10, as a result of the JIS method strength test, the average strength of the liquid crystal panel before optimizing the conditions of each item of the control factor was 10.9 N.
Next, the rotation of the planetary carrier 5 is reversed, the specific gravity of the slurry is 70 g / cm ³ , the slurry particle size is # 1500, the rising time is 19 minutes, the lower platen rotation speed is 35 rpm, and the pressing pressure is set to 15 kPa. As a result, a liquid crystal panel having an average strength of 13.9 N or more was obtained. This satisfies 11N, which is the target strength of the current display panel, and is an improvement of 25%.

In addition, from the graph of FIG. 9A and FIG. 9B, you may select the conditions which have high stability and can maintain intensity | strength at each level.
For example, as shown in the graph of S / N ratio and sensitivity, the strength is certainly higher in the direction of GOOD. However, when the particle size of the slurry is selected as No. 1000, it is easier to obtain than No. 1500, and it can be said that inventory management and the like are easy when manufacturing.
In addition, as for the startup step 4 step, if productivity is given priority, 12 minutes may be selected. The pressing pressure may be 12 kPa when it is desired to reduce damage to the product.

  According to the second embodiment described above, the strength of the object to be polished can be improved by optimizing the condition of each item of the control factor at the time of polishing, that is, the polishing condition.

  In addition, the method of optimizing the conditions of each control factor item at the time of polishing according to the second embodiment is applied to the polishing method using the planet carrier on which the relief portion is formed according to the first embodiment. It is also possible. In this case, the effect which both embodiment has can be acquired.

In the first embodiment, relief portions (notches) formed in the holding holes of the planet carrier are provided at two locations. However, generally, when the rotation of the planet carrier is normal, the load tends to increase with respect to the planet carrier, that is, the object to be polished. Therefore, when the planetary carrier rotates in the forward direction, a cutout may be provided only on one side of the holding hole on the side in contact with the side surface of the object to be polished. Of course, when the planetary carrier rotates in the reverse direction, it is possible to provide an escape portion on the side that comes into contact with the side surface of the object to be polished.
In the case where relief portions are provided on the two sides of the holding hole as in the first embodiment, it is possible to cope with polishing by switching between normal rotation and reverse rotation of the planet carrier.

  In the above-described embodiment, the example in which the polishing apparatus and the polishing method of the present disclosure are applied to the double-sided simultaneous polishing machine has been described. However, the present disclosure is not limited to the double-sided simultaneous polishing machine, but can be applied to any polishing machine that holds the object to be polished on the planetary carrier and presses the surface plate to perform polishing.

In addition, this indication can also take the following structures.
(1)
Upper surface plate,
A lower surface plate disposed opposite to the upper surface plate and rotating in a direction opposite to the upper surface plate,
A sun gear that rotates on the same rotational axis as the upper surface plate and the lower surface plate;
An internal gear that rotates on the same rotation axis as the upper surface plate and the lower surface plate;
A holding hole for holding an object to be polished is formed, and the planetary carrier revolves while revolving by engaging with the sun gear and the internal gear,
The planetary carrier holding hole is provided with a notch on the side of the holding hole that contacts the side of the object to be polished when the planet carrier rotates.
(2)
The polishing apparatus according to (1), wherein the holding hole is substantially rectangular, and the notch is provided on a side of the holding hole that contacts the side surface of the object to be polished when the planet carrier rotates.
(3)
The polishing apparatus according to (1) or (2), wherein the notch is provided on a side of the substantially rectangular holding hole that is in contact with the side surface of the object to be polished and on a side facing the side.
(4)
The polishing apparatus according to (2) or (3), wherein a side of the holding hole that contacts the side surface of the object to be polished corresponds to a rectangular longitudinal direction when the planetary carrier rotates.
(5)
Upper surface plate,
A lower surface plate disposed opposite to the upper surface plate and rotating in a direction opposite to the upper surface plate,
A sun gear that rotates on the same rotational axis as the upper surface plate and the lower surface plate;
An internal gear that rotates on the same rotation axis as the upper surface plate and the lower surface plate;
A holding method for holding an object to be polished, a planetary carrier that revolves while rotating by engaging with the sun gear and the internal gear, and a polishing method for a polishing apparatus comprising:
A polishing method, wherein the holding hole of the planet carrier is provided with a notch on the side of the holding hole that contacts the side surface of the object to be polished when the planet carrier rotates.

  Further, in this specification, the processing steps describing time-series processing are not limited to processing performed in time series according to the described order, but are not necessarily performed in time series, either in parallel or individually. The processing (for example, parallel processing or object processing) is also included.

As described above, the present disclosure is not limited to each of the above-described embodiments, and various other modifications and application examples can be taken without departing from the gist described in the claims. .
That is, the examples of the above-described embodiments are preferable specific examples of the present disclosure, and thus various technically preferable limitations are given. However, the technical scope of the present disclosure is not limited to these forms unless specifically described in each description to limit the present disclosure. For example, the materials used in the following description, the amounts used, the processing time, the processing order, and the numerical conditions of each parameter are only suitable examples, and the dimensions, shapes, and arrangement relationships in the drawings used for the description are also outline. Is something.

  DESCRIPTION OF SYMBOLS 1 ... Upper surface plate, 1A ... Upper surface plate rotation drive part, 2 ... Lower surface plate, 3 ... Sun gear, 4 ... Internal gear, 5 ... Planet carrier, 7 ... Slurry, 10 ... Holding hole, 11a, 11b ... Escape 15, color filter, 16, display panel, Du, rotation direction of upper surface plate, Dl, rotation direction of lower surface plate (planet carrier revolving direction), Di, rotation direction of internal gear, Ds, rotation of sun gear Direction, Dc1 ... planet carrier clockwise (forward), Dc2 ... planet carrier counterclockwise (reverse)

Claims (5)

Upper surface plate,
A lower surface plate disposed opposite to the upper surface plate and rotating in a direction opposite to the upper surface plate,
A sun gear that rotates on the same rotational axis as the upper surface plate and the lower surface plate;
An internal gear that rotates on the same rotation axis as the upper surface plate and the lower surface plate;
A holding hole for holding an object to be polished is formed, and the planetary carrier revolves while revolving by engaging with the sun gear and the internal gear,
The planetary carrier holding hole is provided with a notch on the side of the holding hole that contacts the side of the object to be polished when the planet carrier rotates. The polishing apparatus according to claim 1, wherein the holding hole is substantially rectangular, and the notch is provided on a side of the holding hole that contacts the side surface of the object to be polished when the planet carrier rotates. The polishing apparatus according to claim 2, wherein the notch is provided on a side of the substantially rectangular holding hole that is in contact with a side surface of the object to be polished, and a side facing the side. The polishing apparatus according to claim 3, wherein a side of the holding hole that contacts the side surface of the object to be polished corresponds to a rectangular longitudinal direction when the planetary carrier rotates. Upper surface plate,
A lower surface plate disposed opposite to the upper surface plate and rotating in a direction opposite to the upper surface plate,
A sun gear that rotates on the same rotational axis as the upper surface plate and the lower surface plate;
An internal gear that rotates on the same rotation axis as the upper surface plate and the lower surface plate;
A holding method for holding an object to be polished, a planetary carrier that revolves while rotating by engaging with the sun gear and the internal gear, and a polishing method for a polishing apparatus comprising:
The holding hole of the planet carrier is provided with a notch on the side of the holding hole that contacts the side of the object to be polished when the planet carrier rotates.
A polishing method in which an object to be polished is held in the holding hole provided with the notch of the planetary carrier, and the surface of the object to be polished is polished between the upper surface plate and the lower surface plate.

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