KR20220142581A - A manufacturing method of phosphor chips - Google Patents

Abstract

A phosphor manufacturing method according to one aspect of the present invention comprises the steps of: (1) cutting one surface of a phosphor wafer with a dicing blade so that a plurality of dicing trenches are formed in rows in the wafer; (2) rubbing the surface of the wafer on which the dicing trenches are formed with a polishing pad to curve an angular corner of an outer side surface of the dicing trenches; and (3) cutting a surface of the wafer opposite to the surface on which the dicing trenches are formed by a predetermined thickness with a disc-shaped grinder so that the wafer is individualized into a plurality of phosphors, which are color conversion members for an LED. It is possible to mass-produce a phosphor that has a curved surface on the outside and improves the straightness of passing light.

Description

Phosphor manufacturing method {A MANUFACTURING METHOD OF PHOSPHOR CHIPS}

The present invention relates to a method for manufacturing a phosphor. More particularly, it relates to a method of dividing a large-sized phosphor wafer into small-sized individual chips when manufacturing a phosphor such as a color conversion member for changing the wavelength of light emitted from an LED chip.

Japanese Patent Application Laid-Open No. 2009-96653 (published on May 7, 2009, a prior art document) discloses a method for manufacturing a color conversion member. The color conversion member is attached to the front of the LED chip to convert the wavelength of light emitted from the LED chip. When a fluorescent film is applied to a blue LED as a color conversion member, a white LED can be obtained.

The prior art document discloses a process including a process of mixing glass powder and phosphor powder, a molding process, a firing process, a pressing process, a processing process, etc. as one of several methods for manufacturing a color conversion member. (See FIG. 1 )

In general, after manufacturing the color conversion member in the form of a thin and wide plate, it is divided into several small phosphors in a post-processing process. This is because it is advantageous to reduce the material, time, and process steps required for manufacturing by making a wide phosphor wafer and dividing it into multiple pieces rather than directly making the phosphor with the required size.

A dicing machine is mainly used to cut the wafer into a phosphor of the required size. A rotating dicing blade is installed in the dicing machine. When the dicing blade is rotated and the outer blade moves to penetrate the wafer, cutting is made. The dicing blade may be moved along a straight or curved path to form a phosphor having a desired shape from the wafer.

Meanwhile, Korean Patent Application Laid-Open No. 2016-0116998 discloses a phosphor plate for a vehicle headlamp. The main content of this prior invention is to provide straightness of light passing through the phosphor by forming a curvature on the side surface of the phosphor configured on the upper side of the LED chip.

The embodiments of the present invention provide a manufacturing process capable of simultaneously manufacturing a plurality of curved phosphors at the same time by dividing the color conversion member (phosphor) wafer into individual phosphors, thereby efficiently producing phosphors with improved straightness of light. want to mass-produce.

According to an aspect of the present invention, there is provided a method for manufacturing a phosphor, comprising the steps of: (1) cutting one surface of a phosphor wafer with a dicing blade so that a plurality of dicing trenches are formed in a row on the wafer; (2) rubbing the surface on which the dicing trench is formed of the wafer with a polishing pad to curved an angled corner of an outer side of the dicing trench; (3) cutting the opposite surface of the wafer to a predetermined thickness with a disk-shaped grinder so that the wafer is individualized with a plurality of phosphors that are color conversion members for LEDs; A phosphor having a curved surface that improves the straightness of passing light can be mass-produced.

In addition, the polishing pad is made of a synthetic fiber fabric, and the angular corners are curved while being worn by friction with the polishing pad, and in step (2), the surface on which the dicing trench is formed is downward. and the polishing pad is installed on the lower side of the wafer, the wafer is pressed toward the polishing pad and the polishing pad rotates so that the corners are worn.

In addition, friction particles are dispersedly disposed on the upper surface of the polishing pad, and the friction particles are made of a material having a higher rigidity than that of the polishing pad and the wafer. By being dense in the inner space of the trench, it is possible to accelerate the wear of the corner portion.

Also, between steps (1) and (2), (1-1) when the dicing trench is formed, it is formed outside along the longitudinal direction of the dicing trench, and the dicing blade enters the phosphor wafer. The surface of the wafer on which the dicing trench is formed is uniformly applied to a predetermined thickness with a disk-shaped grinder in order to remove the uneven portions generated on the wafer surface side according to the fine crumbling of particles constituting the wafer generated when It may further include a step of removing;

The method may further include forming a luminance enhancing layer by uniformly depositing a silicon dioxide film on the surface of the wafer on which the dicing trench is formed.

In addition, the dicing trench is formed along a plurality of vertically arranged dicing lines to form rectangular regions to be separated into individual phosphors in the future between the dicing lines. In step (2), the corner portion and to be curved up to the four corners of the quadrangular regions so that the quadrangular region is convex, (2-1) performing a fine grinding operation on the central portion of the convex rectangular region to flatten the curved surface on the central region ; may be further included.

In addition, the dicing blade is of a bevel type whose thickness gradually becomes thinner toward the outside, and in the step (1), the dicing trench is formed to gradually increase in width toward the outside, so that the cross-sectional area gradually increases toward the lower side. The side surface is formed to be inclined, and the corner portion may be curved to manufacture a phosphor.

According to the present invention, a phosphor having an inclined or curved surface formed on the outside to improve the straightness of passing light can be produced in a simple way.

1 is a schematic diagram of a method for manufacturing a phosphor according to an embodiment of the present invention;
2 is a front view and a cross-sectional view showing the result processed by the method for manufacturing a phosphor according to an embodiment of the present invention at each step;
3 and 4 are a front view and a cross-sectional view showing one step of a method for manufacturing a phosphor according to an embodiment of the present invention;
5 and 6 are a perspective view and a cross-sectional view showing a phosphor manufactured by a method for manufacturing a phosphor according to an embodiment of the present invention;
7 is a cross-sectional view illustrating a phosphor manufactured by a method for manufacturing a phosphor according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The accompanying drawings show exemplary forms of the present invention, which are only provided to explain the present invention in more detail, and the technical scope of the present invention is not limited thereby.

In addition, regardless of the reference numerals, the same or corresponding components are given the same reference numerals and redundant description thereof will be omitted, and for convenience of explanation, the size and shape of each component shown may be exaggerated or reduced. have.

On the other hand, terms including an ordinal number, such as first or second, may be used to describe various components, but the components are not limited by the terms, and the terms refer to one component from another. It is used only for distinguishing purposes.

1 is a schematic diagram of a method for manufacturing a phosphor according to an embodiment of the present invention, FIG. 2 is a front view and a cross-sectional view showing the results processed by the method for manufacturing a phosphor according to an embodiment of the present invention at each step, and FIGS. 3 and 4 are the views A front view and a cross-sectional view showing one step of a method for manufacturing a phosphor according to an embodiment of the present invention, FIGS. 5 and 6 are a perspective view and a cross-sectional view showing a phosphor manufactured by the method for manufacturing a phosphor according to an embodiment of the present invention, and FIG. It is a cross-sectional view showing a phosphor manufactured by a method for manufacturing a phosphor according to another embodiment of the present invention. The illustrated roughness, inclination, and the like of the surface of the wafer 1 may be exaggerated in scale than in reality. This is for convenience of explanation.

First, a phosphor wafer 1 to be divided into individual phosphors 11 is prepared. Although the present invention can be applied to various kinds of phosphors 11, in this embodiment, the phosphor 11 as a color conversion phosphor applied to an LED light emitting member will be described as an example. In order to utilize the blue LED as the white LED, the phosphor 11 in the form of a chip or film is widely used. As disclosed in the prior art literature, it is possible to manufacture a disk-shaped wafer 1 by applying processes such as compression and sintering to the fluorescent material powder and the glass powder. The wafer 1 may be manufactured in a rectangular shape.

Since this wafer 1 is not of a size to be applied to an actual product, it must be separated into a small phosphor 11 . In addition, since the surface may be rough or may be made of a curved surface, a planarization operation is required.

Process <1> shown in FIG. 1 is a rough grinding process. As shown in <0> of FIGS. 1 and 2, the freshly manufactured wafer 1 has a flat bottom surface B supported by a support surface G, but a top surface T is uneven or inclined. can As shown in <0> of FIG. 2 , it is common for the upper surface T to have a curved shape because the middle is thin and the outer is thick. If the top surface T is ground with the grinder 21 in the process <1>, a flat top surface T can be obtained as shown in <1> of FIG. 2 . However, the upper surface (T) still has a slight unevenness. Afterwards, it can be smoothed by fine grinding.

The grinding operation may be performed by the surface grinder 21 . The grinder 21 sharpens the surface of the wafer 1 while a wide disk-shaped disk rotates. The thickness of the wafer 1 is uniformly gradually reduced by the grinding operation. A grinding system can be constructed with mechanical equipment including a support for movably supporting the grinder 21 , a support bed for placing the wafer 1 , and a control unit.

In the process <2>, a rough grinding operation may be performed on the bottom surface B by turning the wafer 1 over. The bottom surface (B) is usually not inclined in many cases, but since it may have some fine irregularities, this process can be selectively performed.

In step <3>, the upper surface T of the wafer 1 is cut with the dicing blade 25 . However, this is not to completely cut the wafer 1 and divide it into small phosphors 11 , but to cut the wafer 1 like a slicing only to a partial thickness to form the dicing trench 17 . If a dicing blade 25 having a uniform width is used, a dicing trench 17 having a uniform width can be obtained, and a bevel-type dicing blade 25 that gradually decreases in width toward the outside can be used. In this case, it is possible to obtain the dicing trench 17 which is formed to gradually increase in width toward the outside.

A plurality of straight dicing lines 13 are formed over the entire wafer 1 at regular intervals, and then, a plurality of dicing lines 13 are again formed in a direction perpendicular to the straight line. A rectangular area formed between the dicing lines 13 corresponds to the width of the phosphor 11 to be finally cut.

At this time, as shown in <3> of FIG. 2 , fine crushed portions 18 are formed on both side portions of the upper end of the dicing trench 17 , that is, on the portion where the upper side of the side surface of the phosphor 11 will be formed in the future. . Since the surface of the wafer 1 is the portion that receives the dicing blade 25 in the front and is the interface between the wafer 1 and the outside, more material is removed by the rotation of the dicing blade 25 . The wafer 1 is a group of several grains, and as the dicing blade 25 enters, these grains are torn off, and mainly the grains are torn off non-uniformly from the surface of the wafer 1 . That is, most of the fine crushed portions 18 are formed on the surface side of the wafer 1 .

This fine crushed portion 18 is a cause of making the upper surface edge and side surface of the phosphor 11 uneven, and it is necessary to remove it to obtain a smooth phosphor 11 . Furthermore, in step <5>, which will be described later, a curved surface is formed on the phosphor 11 with the polishing pad 30. Since the uneven surface of the fine crushed portion 18 is randomly and non-uniformly formed, the curved surface may also become non-uniform. can Details will be described later.

In order to remove the fine crushed portion 18, in the process <4> of FIG. 1, the upper surface of the dicing trench 17, that is, the upper surface T of the wafer 1, is again subjected to rough grinding. When the rough grinding is completed, the fine crushed portion 18 is deleted as shown in <4> of FIG. 2 . However, the fine irregularities still remain. If a grinder 21 that is too coarse in this process is used, it is advantageous to delete the fine crushed portion 18, but a rough surface may be obtained. It could take too long. The roughness of the grinder 21 may be selected in consideration of the roughness required in the final product, the required work time, the reliability of equipment, and the like.

In step <5> of FIG. 1 , a polishing operation is performed on the surface of the wafer 1 on which the dicing trench 17 is formed. As shown in <5> and FIG. 3 of FIGS. 1 and 2 , the surface on which the dicing trench 17 is formed is downward and it is brought into close contact with the polishing pad 30 . A driving device (not shown) for rotating the polishing pad 30 may be installed below the polishing pad 30 . The wafer 1 is positioned above the polishing pad 30 and pressed downward to bring the wafer 1 and the polishing pad 30 into close contact. In this state, if the polishing pad 30 is rotated at a high speed, the polishing pad 30 and the surface of the wafer 1 rub against each other. As a result of friction, the uneven portion of the wafer 1 becomes smooth.

The polishing pad 30 may be made of a synthetic resin material, for example, a polyurethane material. Since a soft fabric protrudes over the entire polishing pad 30 , when the polishing pad 30 and the wafer 1 are rubbed, the fine particles on the surface of the wafer 1 are removed to smooth the uneven area. As the material of the polishing pad 30, a rougher and higher rigid metal may be used or friction may be performed as a fiber rather than a fabric, but in order to make a smoother surface, it is better to use a soft material.

The friction particles 35 may be sprinkled on the surface of the polishing pad 30 . The friction particles 35 are very small synthetic diamond powder particles, and if they are evenly arranged over the polishing pad 30 , they can help the friction action while being sandwiched between the polishing pad 30 and the wafer 1 . Since the friction particles 35 are fine particles, they only smooth the surface of the wafer 1 without increasing the roughness, and have high rigidity, which accelerates the friction of the wafer 1 .

When the wafer 1 is polished with the polishing pad 30 in this way, the roughness of the surface of the wafer 1 is reduced. At the same time, the angled corner portions 39 on both sides of the outer side of the dicing trench 17 are worn to form a curved surface. Since the dicing trench 17 is formed in the flat wafer 1, the corner portion 39 is naturally formed at a right angle. The corner portion 39 is a portion corresponding to between the upper surface and the side surface of each of the phosphors 11 when the wafer 1 is separated into a plurality of phosphors 11 in the future.

When the surface of the wafer 1 is worn by the friction particles 35 and the polishing pad 30, rather than uniformly worn as a whole, the degree of abrasion in areas such as the edge portion 39 around the dicing trench 17 is more become big This is because the angular portion rubs the polishing pad 30 and the friction particles 35 better than the flat portion. In particular, since a space is formed inside the dicing trench 17, the friction particles 35 better stay in this area, and the wear of the corner portion 39 is reduced by the friction particles 35 driven toward the dicing trench 17. can be aggravated

As the surface of the wafer 1 is rubbed, the fine particles that fall off go down to the lower polishing pad 30 by their own weight, so they also act as the friction particles 35 .

During step <5>, the surface of the wafer 1 became smooth, and at the same time, the edge portion 39 on the side of the dicing trench 17 had a curved surface. In the previous step <4>, the fine crumb 18 was removed by the rough grinding operation. If the polishing operation of step <5> is performed in a state in which the fine crushed portion 18 remains as it is without step <4>, the curved surface may not be uniformly formed. Since the fine crushed portion 18 is a region where the particles constituting the wafer 1 are non-uniformly and randomly separated, the edge portion 39 of the surface of the wafer 1 is also non-uniform. Even if the polishing operation is performed on the non-uniform edge portion 39 in this way, a non-uniform curved surface will be formed in the same manner. Therefore, a uniform curved surface can be obtained only when the polishing operation of step <5> is performed in a state in which the fine crushed portion 18 is removed through the grinding operation of step <4>.

In the process <6> of FIG. 1 , the wafer 1 is finally divided into the phosphor 11 . A rough grinding operation is performed on the bottom surface (B) with the dicing trench 17 facing downward. The thickness of the wafer 1 is gradually reduced from the bottom surface B by the rough grinding operation. If the operation is continued as shown in FIG. 4 , the grinder 21 finally reaches the dicing trench 17 . As a result, as shown in FIG. 2 and FIG. 4, the wafer 1 is separated into several small phosphors 11 accordingly. In addition, if the grinder 21 is moved further down even after separation, the thickness of the phosphors 11 may be further reduced. This may continue until the desired phosphor 11 thickness is achieved. That is, through the <6> process, the separation of the phosphor 11 and thickness adjustment can be completed.

If necessary, the roughness of the bottom surface B may be reduced by performing fine grinding on the bottom surface B of the wafer 1 with the fine grinder 22 . Coarse grinding and fine grinding are relative concepts. The roughness of coarse grinding and fine grinding may be determined according to the characteristics of the material and required specifications. Of course, the resultant roughness of the coarse grinding and the fine grinding will be set so that the roughness of the fine grinding work is smaller than that of the coarse grinding. From the point of view, coarse grinding is intended to reduce roughness while substantially reducing the thickness of the wafer, and fine grinding is a polishing operation performed for the purpose of further reducing roughness rather than reducing the thickness.

A plurality of phosphors 11 shown in FIGS. 5 and 6 can be obtained through the above processes. 5 and 6, the results of various phosphors 11 having different shapes are shown as (a), (b), (c), and (d). The same type of phosphor 11 is indicated by the same label as a perspective view in FIG. 5 and a cross-sectional view in FIG. 6 . Processes for obtaining this for each phosphor 11 are somewhat different.

Although the phosphors 11 shown in FIGS. 5 and 6 have slightly different shapes, all the phosphors 11 have in common that the corners between the top and side surfaces of the phosphors 11 are curved. When the outer side of the phosphor forms a curved surface in this way, as disclosed in Korean Patent Application Laid-Open No. 2016-0116998, the light passing through the phosphor does not spread but is concentrated at the center. Accordingly, the straightness of the light may increase and the quality of the light may be improved.

5 and 6 (a) are results obtained by a general polishing process <5>. It can be seen that the corner portion between the upper surface and the side surface is curved.

5 and 6 (b) shows that the polishing process <5> is performed relatively longer and more strongly, so that not only the corner 34 between the upper surface and the side surface of the phosphor 11 but also the four corners 32 of the upper surface are curved. The phosphor 11 having a shape is shown. In this case, since the dicing trench 17 is formed deeper from the beginning than in other cases, the phosphor 11 having a certain thickness can be preserved even if worn by the polishing process <5>.

5 and 6 (c) can be obtained by adding one more task to the result of (b). That is, (c) the phosphor 11 is obtained by performing a fine grinding operation on the upper surface of the phosphor 11 (b) to flatten the curved surface of the upper surface of the phosphor 11 at the center 33 .

As described above, the light could be focused on the outside of the phosphor 11 by making it curved. (b) In the case of the phosphor 11, it is advantageous in terms of improving the optical straightness because the outside can be curved more than that of (a) the phosphor 11. However, as the polishing process <5> is performed for a long period of time, the curvature may be deepened to the central portion 33 of the phosphor 11 rather than the outside. In order to secure the optical straightness, it is necessary to make the outer side of the phosphor 11 curved, but it is not necessary to make it curved up to the center portion 33 of the phosphor 11 . This is because the light of the central portion 33 of the phosphor 11 does not spread well to the outside anyway. Moreover, if the central portion 33 of the phosphor 11 is curved, a weakness may occur such as an increase in volume or an unnecessary gap between the phosphor 11 and other components when modularizing the phosphor 11 together with an LED chip. can In addition, if the polishing process <5> is performed uniformly, the plurality of phosphors 11 derived from one wafer 1 will have the same shape. A deviation may occur between the phosphors 11 in the curved shape. If the upper surface of the phosphor 11 is subjected to a fine grinding operation to flatten the curved surface of the upper surface of the phosphor 11 at the center 33, this concern can also be eliminated.

The operation of flattening the upper surface central portion 33 of the phosphor 11 by grinding may be performed between the polishing step <5> and the phosphor individualization step <6>, and after completing the steps <5> and <6> The entire individual phosphor 11 may be turned over at the same time, and a grinding operation may be performed thereon.

On the other hand, the phosphor 11 of FIGS. 5 and 6 (d) is a result of only curving the corners between the upper surface and the side surface and between the side surface, like the phosphor 11 (a). However, the four side surfaces of the phosphor 11 are inclined and are formed in a form in which the cross-sectional area gradually increases toward the lower side. In the polishing step <5>, the amount of wear is too large to wear the side surface of the phosphor 11 to form the inclined surface. When the bevel-type dicing blade 25 is used in the dicing trench formation process <3> before the polishing step <5>, such an inclined side surface can be obtained. Here, the result of polishing only the corner portion 36 by performing the polishing process <5> is (d) the phosphor 11 . Even if it is not a curved surface (d), the inclined surface 37 on the side of the phosphor 11 will also help to improve the straightness of the light.

7 shows a phosphor 11 coated with a luminance enhancing layer 40 on its surface. As an example, although only the phosphor 11 coated with the luminance enhancing layer 40 is illustrated in FIGS. The luminance enhancing layer 40 may be formed using silicon dioxide (SiO2, silica) as a material. As the light generated from the LED chip passes through the phosphor 11 , the wavelength of the light is converted, the straightness is enhanced, and the luminance may be improved while passing through the luminance enhancing layer 40 outside the phosphor 11 .

The luminance enhancing layer 40 using silicon dioxide as a material may be formed by a film deposition method. The wafer 1 is fixed with the side on which the dicing trench 17 is formed in the vacuum chamber facing down, and the silicon dioxide crystal placed thereunder is evaporated with a brightness enhancing layer forming apparatus until a film of a desired thickness is formed. (1) A method of allowing silicon dioxide vapor to condense on the surface is an example. Examples of the method for evaporating the silicon dioxide crystal include thermal evaporation, electron beam evaporation, and sputtering.

The step of forming the luminance enhancing layer 40 may be performed between the polishing step <5> and the phosphor individualization step <6>. The luminance enhancing layer 40 may be formed on the upper surface of the phosphor 11 and the curved surface formed in the polishing process <5>. The lower surface of the phosphor 11 is a portion in contact with the LED chip, and the luminance enhancing layer 40 should not be formed.

A technique for improving the straightness of light by making the outer portion of the phosphor 11 curved has been disclosed in the prior art. The embodiment of the present invention is improved so that a large amount of curved phosphors 11 can be manufactured from the wafer 1 in a simple manner.

In the above, although embodiments of the present invention have been described, those of ordinary skill in the art can add, change, delete or add components within the scope that does not depart from the spirit of the present invention described in the claims. The present invention may be variously modified and changed by such as, and it will be said that it is also included within the scope of the present invention.

One; wafer 11; phosphor
13; dicing line 17; dicing trench
21, 22; grinder 25; dicing blade
30; polishing pad

Claims (7)

(1) cutting one surface of the phosphor wafer with a dicing blade so that a plurality of dicing trenches are formed in a row in the wafer;
(2) rubbing the surface on which the dicing trench is formed of the wafer with a polishing pad to curved an angled corner of an outer side of the dicing trench;
(3) cutting the opposite surface of the wafer to a predetermined thickness with a disk-shaped grinder so that the wafer is individualized with a plurality of phosphors that are color conversion members for LEDs; A phosphor manufacturing method for mass production of phosphors having a curved surface and improving the straightness of passing light. According to claim 1,
The polishing pad is made of a synthetic fiber fabric,
The angled corner is curved while being worn by friction with the polishing pad,
In the step (2), the surface of the wafer on which the dicing trench is formed is downward and the polishing pad is installed on the lower side of the wafer, the wafer is pressed toward the polishing pad and the polishing pad rotates while the corner portion is A method of manufacturing a phosphor to be worn. 3. The method of claim 2,
Friction particles are dispersed and disposed on the upper surface of the polishing pad,
The friction particles are made of a material having a higher rigidity than the polishing pad and the wafer,
In the step (2), the friction particles are concentrated in the inner space of the dicing trench, thereby accelerating the wear of the corner portion. The method according to claim 1, wherein between steps (1) and (2),
(1-1) When the dicing trench is formed, it is formed on the outside along the longitudinal direction of the dicing trench, and when the dicing blade enters the phosphor wafer, the fine crumbling of the particles constituting the wafer occurs. and uniformly removing the surface of the wafer on which the dicing trench is formed by a predetermined thickness with a disk-shaped grinder in order to remove the uneven portions generated on the wafer surface side. According to claim 1,
and forming a luminance enhancing layer by uniformly depositing a silicon dioxide film on the surface of the wafer on which the dicing trench is formed. The method of claim 1,
The dicing trench is formed along a plurality of vertically arranged dicing lines, and rectangular regions to be separated into individual phosphors are formed between the dicing lines.
In the step (2), the corner portion and the four corners of the rectangular regions are curved so that the rectangular region is convex,
(2-1) performing a fine grinding operation on the central portion of the convex rectangular region to flatten the curved surface on the central portion; The method of claim 1,
The dicing blade is of a bevel type that gradually decreases in thickness toward the outside,
In the step (1), the dicing trench is formed to gradually increase in width toward the outside,
A method for manufacturing a phosphor in which the side surface is formed to be inclined so that the cross-sectional area gradually increases toward the lower side, and the corner portion is curved to manufacture a phosphor.

Images