JP2002283206A - Projected substance polishing method and polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projected substance polishing device adopting the optimum quality judgment value corresponding to a shape of the projected substance existing on a base plate. SOLUTION: When the projected substance existing on a surface of a color filter for a liquid crystal panel is polished, a judgment value different before and after the polishing is used for a quality judgment of height of the projected substance. A right or wrong of the polishing of the projected substance is determined by a height judgment value, before polished, of the quality judgment value and the quality judgment of the projected substance is carried out by the height judgment value after polished. Thereby, the optimum quality judgment is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes it possible to make a proper pass / fail judgment on the basis of a height measurement result when polishing and correcting a projection present on a substrate surface such as a color filter for a liquid crystal panel. The present invention relates to a polishing method and a polishing apparatus.

[0002]

2. Description of the Related Art When projections are present on a substrate such as a color filter for a liquid crystal panel, a transparent electrode on the color filter side and a thin film transistor (TF) are used during the production of a liquid crystal display.
T) The pixel electrode on the TFT substrate side on which the TFT is formed is short-circuited by a foreign substance, which may cause a display failure of the liquid crystal. If there is a projection on the pixel electrode that is larger than the panel gap, the gap becomes uneven and the display quality deteriorates. There is. For this reason, it is necessary to prevent the short-circuit with the counter electrode by polishing the protrusion to make the height within an allowable range.

When polishing and correcting projections on the surface of a substrate such as a color filter for a liquid crystal panel, a special consideration must be given to the height. Therefore, the height of the projection is measured and compared with a required standard value. It is generally performed to make a pass / fail judgment. As the height measuring method, a contact type in which measurement is directly performed with a stylus or the like and a non-contact type in which measurement is performed by using optical characteristics. Although the measurement can be performed by either method, the non-contact method is mainly used on the substrate surface having a soft film quality in order to prevent scratches and secondary contamination. However, regarding the height measurement, the height measurement using an optical measuring instrument causes variation in the scattered light detected due to the shape of the protrusion, which tends to cause an error in the measurement value, and the height measurement value becomes unstable. Sometimes. Further, in a contact-type measuring instrument, it is not possible to stably measure the maximum height of the projection due to a deviation of the contact coordinate position of the projection, so that a variation in the measured passing value may occur. It is difficult to accurately measure the height before polishing using either measuring instrument.Depending on the measurement conditions, consider the protrusion defect protrusion to the next process or, conversely, too much measurement error to prevent the flow. If the determination value is made too strict, a problem arises in that a projection which should be originally determined to be a non-defective product is erroneously determined to be a defect and the yield is reduced.

[0004]

SUMMARY OF THE INVENTION According to the present invention, an appropriate polishing method and conditions are used for correcting a projection to flatten the tip shape after polishing of the projection and to bring the tip shape close to a flat surface, thereby achieving optical improvement. It focuses on improving the accuracy of foreign matter height measurement with a measuring device and a stylus-type measuring device before polishing, and the issue is to determine the optimal quality based on changes in the shape of the protrusions before and after polishing. An object of the present invention is to provide a projection polishing method and a polishing apparatus which can adopt a value and can efficiently produce a high-quality product with no projection outflow without erroneous determination.

[0005]

The present invention employs the following configuration to achieve the above object. That is, (1) measuring the height of the protrusions present on the substrate and determining whether or not the protrusions can be polished based on the height determination value of the protrusions before polishing the protrusions when determining the quality of the protrusions. A method of polishing a projection, comprising determining the quality of the projection using a determined height after polishing.

(2) A projection polishing apparatus comprising: a mechanism for measuring the height of a projection existing on a substrate; and a judging means for judging the height of the projection before and after polishing.

(3) The projection polishing apparatus according to (2), further comprising a judging means for determining the height of the projection before and after polishing.

(4) The protrusion polishing apparatus according to (2) or (3), wherein a measuring device using laser light is used as the protrusion height measuring mechanism.

(5) The projection polishing apparatus according to any one of (2) to (4), wherein the projection is partially polished by using a polishing tape as a method of polishing the projection.

(6) As the projection polishing mechanism, it is preferable that the polishing head has a flat surface portion of 0.0025 to 2.25 mm 2 at a contact portion of a polishing head portion which holds a polishing tape and contacts the projection to polish the polishing tape. The protrusion polishing apparatus according to any one of the above (2) to (5).

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described with reference to the flowchart of FIG. 1. First, a foreign matter height T1 before polishing is measured by a foreign matter height measuring mechanism provided in the present apparatus. Either a contact type or a non-contact type may be used as the foreign matter height measuring mechanism, but it is preferable to use a non-contact type in terms of preventing scratches on the substrate surface and secondary contamination, and furthermore, the inclination and the inclination of the measured object. It is more preferable to use a laser microscope which is hardly affected by a vertical step in the surface shape. Foreign matter height determination value t1 before polishing that determines whether or not polishing is possible
In order to improve the quality of the target substrate and prevent the outflow of defects, it is preferable to set the quality standard value to a stricter value in which an error of a measuring instrument is added.

As for the foreign matter after polishing, when a rotary polishing apparatus using silica or alumina fine particles is used, the fine projections on the surface of the projections are removed, the surface shape becomes a gentle slope, and the projection height accuracy using a laser microscope is improved. improves. Also,
By adopting tape polishing, the protrusions are selectively and positively polished from the tip, so that the polished protrusions can be trapezoidal with flat vertices. Improve dramatically.

Therefore, the post-polishing foreign matter height determination value t2 for determining the quality of the post-polishing projection height T2 is preferably a strict value in which the error of the height measuring device is added to the quality standard value. In order to suppress a decrease in yield due to over-detection of defects, adopt a value that corrects the error added to the quality standard value by the improvement of the measurement accuracy, and use the value of the product that was conventionally considered to be difficult to achieve. It is possible to satisfy both quality improvement and high yield.

As a polishing method, there are a rotary polishing, a wide range of pixel ground tape polishing, a partial polishing for selectively polishing only protrusions, and the like.

The rotary polishing includes, for example, CMP (Chemical Mechanical Polishing), but is not particularly limited. From the viewpoint of effective polishing, it is preferable to use a slurry using a low-grain fine powder such as alumina, silica, chromium oxide, cerium oxide, and zirconia. It is preferable that particles having a particle size of 0.001 to 1.0 μm are included. As the polishing cloth, a nonwoven fabric, a foamed cloth such as polyurethane, a suede, and the like are preferable. For example, a substrate is placed on a supporting surface plate, and a rotating plate having a pad material is placed thereon while flowing an appropriate slurry (abrasive material) on the substrate to perform rotational polishing.

For a wide range of pixel ground tape polishing,
For example, a polishing tape is pressed and polished while pressing the polishing tape with a roller on a substrate with a ground area equal to or larger than the pixel pitch with a rubber roller, and then the whole area of the pixel is polished by scanning.

For partial polishing in which only the protrusions are partially polished, there are intermediate products such as an unprocessed substrate, a color filter substrate and a black matrix, an RGB color process, a protective film process, an ITO sputtering process, a thin film transistor array substrate, and a thin film diode. Substrate, PDP substrate, driving electrode such as organic / inorganic EL, glass, plastic having colored layer, their substrate or film with reflective film etc. By irradiating the surface and detecting laser scattered light while scanning the entire substrate, the defect and its defect coordinate data are investigated in advance using a defect detection device that detects defects, and data storage and partial Data is transmitted to the polishing device. The detected defect information is read by the polishing apparatus, and the polishing apparatus detects whether or not the projection is on the corresponding coordinates, and measures the height before polishing. Here, the height is measured using a laser microscope, a stylus-type measuring instrument, or the like.

As the polishing apparatus in the present invention, an integrated apparatus having a polishing section and a height measuring function on the same work, and an apparatus in which the polishing section and the height measuring section are connected by a transfer robot and / or a transfer conveyor or the like. And systematized devices can be employed.

Next, the height of the protrusion before polishing is determined,
Determine if partial polishing is required. Height measurement value before polishing T
If 1 exceeds the set allowable value t1, partial polishing is performed. Here, for example, when the product standard value of the protrusion exceeds 5 μm, in the case of NG, if the measurement accuracy due to shape variation of the protrusion height before polishing is ± 2.0 μm, the protrusion height before polishing is 3.0 μm or more. The process is sent to a partial polishing step to partially polish the protrusions.

After polishing, the height T2 of the protrusion is measured again. Here, the side cross section having a flat portion at the apex of the shape of the protrusion after polishing has a trapezoidal height, and the height measurement accuracy is improved by using a laser microscope, and the measurement accuracy is ± 0.5 μm. Therefore, for example, the criterion t2 of the polishing height after polishing is set to a product standard value of 5 μm.
0.5 is taken into consideration, and less than 4.5 μm is regarded as a good product.
m or more can be NG. 3. In the case of NG after one polishing, the polishing is repeated again.
A non-defective product having a thickness of less than 5 μm can be appropriately implemented.

In the present invention, different judgment values are set for the height of the protrusion before and after polishing. That is, t
1 <t2. As for the determination value t2 after polishing, an expected error can be estimated to be small in anticipation of improvement in measurement accuracy after polishing. Conversely, the pre-polishing determination value t1 estimates the error largely because the measurement accuracy is poor. Further, it is more effective to make t2 0.5 to 1.5 μm or more larger than t1.

On the other hand, in the partial tape polishing, there is no direct contact with the pixel and there is no fear of generation of scratches on the pixel surface. Therefore, depending on the type of the projection, for example, a metal-based projection may require a polishing tape bound with hard particles. Can be used. As the polishing material for the tape, a material obtained by coating the tape with a fine powder such as alumina, silica, zirconia, diamond, silicon carbide, cerium oxide, stainless steel or the like with a binder such as polyurethane can be appropriately used. The abrasive particles used in the polishing tape are preferably finely divided for the purpose of improving the ground flatness of the polishing, and more preferably have an average particle diameter of 0.6 μm or less, more preferably 0.1 μm or less.

Further, in order to obtain a more stable polishing height after polishing and a stable shape in which protrusions such as burrs and horns do not occur, the polishing head holding the polishing tape 1 must be a polishing head as shown in FIG. A portion 4 having a flat and substantially flat surface at least at an apex 3 and at least the area of the projection to be polished;
It is important to have The flat and substantially flat portion 4 has an area of 0.0025 to 2.50 in consideration of an alignment error between the protrusion and the polishing head vertex 3.
25 square mm. More preferably,
0.01 to 1.0 mm2. further,
The flat and substantially flat portion of the apex of the polishing head depends on the flat surface and the contact area, but as shown in FIG.
If the curvature is R = 400 μm or more, the contact area can be said to be substantially flat. More preferably, R = 1000 μm
That is all. For example, as shown in FIG. 5, the length of a chord in contact with a circumference having a curvature R = 2500 μm is 200 μm.
In this case, the distance from the center of the chord to the circumference is 2 μm, and such a curvature is regarded as a substantially planar shape. Further, it is more preferable that the portion 4 which is flat and substantially flat from the distribution of the protrusion shapes is circular and elliptical.

In FIG. 5, the length λ of the dotted line is 1
00.0199998, sin θ = 100 / λ θ = 88.854 ω = 180−2θ = 2.292 tan ω = 100 / (R−2) R = 100 / tan ω + 2 R = 2500.48

Furthermore, a flat, substantially planar portion 4
When making a circular shape and an elliptical shape, the polishing tape 1 is brought into close contact with the polishing head vertex 3 without any gap,
Although the danger of the tape edge contacting the substrate can be avoided, the tape guides 5 are provided on both sides of the apex 3 of the polishing head because there is a possibility of the polishing tape 1 meandering or slipping off.
Is more preferable. Next, in order to bring the polishing tape 1 into close contact with the polishing head vertex 3 without any gap, the tape entry angle α to the polishing head vertex 3 is important, and the tape entry angle α is set to 45 degrees or less, more preferably. It is preferable that the angle be 3 degrees to 25 degrees. If the angle is less than 3 degrees, there is a risk that the tape edge contacts the pixel due to the tension fluctuation, and there is a danger of scratching. Guide roll 2 to determine approach angle
It is more preferable that the distance between the polishing head apex 3 and the polishing head 3 be 5 mm or more to improve the running stability of the tape.

[0026]

(Embodiment 1) The present invention will be described below with reference to embodiments. A laser microscope, which is an optical measuring device, was used for measuring the height of the foreign matter. A protective film was applied to the substrate on which the standard foreign matter sample was scattered, and a heat-cured standard substrate was prepared. The height T1 of the foreign matter before polishing was repeatedly measured.
It was 2.0 μm. The pre-polished foreign matter height determination value t1 was determined to be 3 μm or more in consideration of the required quality of less than 5 μm and the measurement error of 2 μm. As shown in FIG. 3, the substrate obtained by rotary polishing 6 using an alumina slurry was set at level A, and a wide range of pixel ground tape was polished so that scratches would not be caused by grounding pixels having a ground width of 40 mm, as shown in FIG. A substrate polished using a wide tape 7 coated with a film of a relatively low-hardness silica fine-particle powder on a film with a binder is used for level B, and alumina fine-particle fine powder is used for partial polishing.
A 3.8 mm wide polishing tape coated with a binder was used. Here, the polishing material was alumina fine powder because it did not directly contact the pixels. The sample polished using this partial polishing tape was set to level C. Further, the polishing was carried out in the same manner as the level C except that a polishing head having a flat circular flat portion 8 (area 0.2 mm 2) was used, and the level D was obtained.

In the case of using the same judgment value before and after polishing as in the prior art (Comparative Examples 1 and 2), the judgment value of the height after polishing was set to 4 μm in consideration of improvement in measurement accuracy. Table 1 shows the pass rate of defects after polishing and the outflow rate of defects after polishing in the cases (Examples 1 to 4). The NG of the defect and the outflow rate were determined based on the projection height obtained from the depth of focus of the visual inspection using an optical microscope, which is a product inspection method. As shown in the results of Table 1, when the judgment values before and after polishing were set to the same value,
In Comparative Example 1 in which the measurement error was sufficiently taken into consideration, the polishing pass rate was low, and in Comparative Example 2, in which the measurement error was estimated to be small, the outflow rate was high, and any good results could not be obtained. In Examples 1 to 4 in which the judgment values before and after polishing were changed, the polishing pass rate exceeded 80% and the outflow rate was 20 or less, which was good. In particular, in Example 3 of partial tape polishing and Example 4 in which the shape of the polishing head was a flat flat surface, the shape of the protrusion after polishing was stabilized, and the polishing success rate was extremely good.

[0028]

[Table 1]

(Embodiment 2) FIG. 4 is a flowchart showing another embodiment of the present invention. In the present embodiment, the foreign matter polishing of the color filter which requires the height of the foreign matter on the substrate to be less than 4 μm was performed. The foreign matter height T1 before polishing was determined using the above-described determination value t1, and polishing was performed for a foreign matter height T1 of t1 or more. The post-polishing foreign matter height T2 was determined using the above-described determination value t2, and a foreign matter having a height T2 less than t2 was determined to be non-defective. In the present embodiment, a foreign matter whose height T2 after polishing is determined to be not less than t2 is not immediately determined to be defective, but is re-polished by limiting the number of times. Levels A, B,
When the quality of the polished product was confirmed twice for both C and D, the levels A and B did not change in the height level and the variation even when re-polishing was performed. In addition to the height improvement, it was confirmed that the height variation after polishing was improved.

[0030]

According to the present invention, by using different judgment values before and after polishing for judging the quality of the foreign matter, the quality judgment value taking into account the measurement error due to the foreign matter shape can be selectively used according to the change in the shape of the foreign matter. Becomes possible.

Further, by determining whether or not the foreign matter can be polished based on the height judgment value before polishing and determining whether the foreign matter is good or bad with the height judgment value after polishing, a judgment value suitable for the purpose can be used.

That is, foreign matter before polishing with a low accuracy of the measured value is determined to be polished by a judgment value in which errors are sufficiently taken into consideration, and foreign matter after polishing with a high accuracy of the measured value has a judgment value closer to the quality standard value. By using this, protrusion defect outflow to the next process due to unstable height measurement value, and conversely, by making the judgment value stricter in consideration of measurement error, protrusions that should be judged as good This solves the problem of erroneously determining a non-defective product, and is effective in improving quality and reducing costs.

Further, by using a measuring device using a laser beam as a projection height measuring mechanism or using a polishing tape as a polishing method of the projection, the accuracy of measuring the height of the projection after polishing is improved. The height measurement accuracy is greatly improved due to the synergistic effect of adopting both.

As a projection polishing mechanism, a flat and substantially flat portion of 0.0025 to 2.25 mm 2 is provided at a contact portion of a polishing head portion which holds a polishing tape and makes contact with the projection to polish the polishing tape. It is an effective means to shorten the production tact time and improve the production efficiency by improving the successful polishing rate and reducing the number of polishing times of the multiple polishing of the projection polishing.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a preferred embodiment of the present invention.

FIG. 2 is a configuration diagram showing one embodiment of a polishing tape type foreign matter polishing apparatus according to the present invention.

FIG. 3 is a diagram showing a comparative example of a polishing method level and a projection shape before and after polishing.

FIG. 4 is a flowchart showing another embodiment of the present invention.

FIG. 5 is an embodiment view of a substantially planar portion in the present invention.

[Explanation of symbols]

 1: Polishing tape 2: Tape guide 3: Polishing head 4: Polishing head apex flat portion 5: Tape guide 6: Rotary polishing 7: Wide tape 8: Flat circular flat portion

Continued on the front page F-term (reference) 3C058 AA05 AA09 AC02 BA02 BA07 BB01 BB09 CA01 CB03 CB10

Claims (6)

[Claims] 1. A method for measuring the height of a projection present on a substrate,
When judging the quality of the protrusion, determine whether or not the protrusion can be polished by the height judgment value of the protrusion before polishing the protrusion, and perform the quality judgment of the protrusion by the height judgment value after polishing. A projection polishing method characterized by the above-mentioned. 2. A projection polishing apparatus, comprising: a mechanism for measuring the height of a projection existing on a substrate; and a judging means for judging the height of the projection before and after polishing. 3. The projection polishing apparatus according to claim 2, further comprising means for judging the height of the projection before and after polishing. 4. The protrusion polishing apparatus according to claim 2, wherein a measuring device using laser light is used as the protrusion height measuring mechanism. 5. The projection polishing apparatus according to claim 2, wherein a polishing tape is used as the projection polishing method, and the projection is partially polished. 6. The projection polishing mechanism, wherein a contact portion of a polishing head portion which holds a polishing tape and makes contact with the projection to polish the polishing tape has a flat substantially flat surface of 0.0025 to 2.25 square mm. A part having a portion.
The projection polishing apparatus according to any one of the above.