JP2010161221A - Method of manufacturing mounting substrate, mounting substrate, and light emitting device - Google Patents

Abstract

A method of manufacturing a mounting board capable of improving productivity, a mounting board manufactured by the manufacturing method, and a light emitting device including the mounting board are provided.
A plurality of light emitting elements formed in a lattice pattern on one surface of a wafer 100, and then a region (effective pixel) in which various characteristics among the plurality of light emitting elements formed on the wafer 100 do not vary greatly. Region 100A) is selected. Next, after transferring a plurality of light emitting elements included in the effective pixel region 100A to the transfer substrate 200 collectively for each line or a plurality of lines, the plurality of light emitting elements after being transferred to the transfer substrate 200 are The transfer is performed collectively on the transfer substrate 300 for each line or a plurality of lines.
[Selection] Figure 6

Description

  The present invention relates to a mounting substrate manufacturing method in which a light emitting element is mounted on a substrate, a mounting substrate manufactured by the manufacturing method, and a light emitting device including the mounting substrate.

  In recent years, LEDs (Light Emitting Diodes) have been used in various devices such as backlights of liquid crystal display devices, display panels of LED display devices, and lighting fixtures. Along with this, there has been a strong demand for cost reduction of LEDs. In order to reduce the cost of LEDs, for example, it is necessary to improve productivity, select inexpensive materials, and the like.

  For example, in order to improve productivity, it is common to reduce the chip size and take a large number of LEDs from a single wafer. In recent years, the chip size has become extremely small, for example, 20 μm, and it has become difficult to handle the LED chip alone. Therefore, it is not practical to mount individual LED chips on a circuit board using a mounter.

  Therefore, conventionally, for example, enlarged transfer described below is performed instead of mounting by a mounter (see Patent Document 1). First, a support wafer having an adhesive layer on the surface is prepared. Next, the surface on the adhesive layer side of the supporting wafer is brought into contact with the surface on the light emitting element side of the wafer in which a plurality of light emitting elements are formed in a matrix on the substrate, and then the light emitting element is removed from the wafer by laser lift-off. Are peeled at predetermined intervals and transferred to a supporting wafer. Thereby, the arrangement pitch of the light emitting elements becomes sparse. Next, a circuit board on which connection electrodes are formed at a pitch equal to the arrangement pitch of the sparsely arranged light emitting elements is prepared, and the light emitting elements attached to the support wafer are transferred to the circuit board. In this manner, a mounting board in which the light emitting element is mounted on the circuit board can be manufactured.

JP 2002-182580 A

  By the way, as a method for mounting the light emitting elements on the circuit board, for example, it is conceivable to transfer the light emitting elements formed in a matrix on the wafer one by one to the circuit board. However, with this method, for example, when producing a large display device in which the number of light-emitting elements mounted on a single display panel reaches the level of millions, transfer of millions of times is required. Therefore, productivity is remarkably low. Such a problem can occur not only in a display device but also in a large-sized backlight, a lighting device, or the like.

  The present invention has been made in view of such problems, and an object thereof is to provide a mounting substrate manufacturing method capable of improving productivity, a mounting substrate manufactured by the manufacturing method, and a light emitting device including the mounting substrate. It is to provide.

The manufacturing method of the mounting substrate of the present invention includes the following steps.
(A1) a first step of collectively transferring a plurality of light emitting elements included in a predetermined region of the first substrate on which a plurality of light emitting elements are formed in a matrix to a second substrate for each line or a plurality of lines ( A2) Second step of transferring a plurality of light emitting elements after being transferred to the second substrate to the third substrate in a lump for each line or every plurality of lines.

  In the mounting substrate manufacturing method of the present invention, a plurality of light emitting elements included in a predetermined region of the first substrate in which the plurality of light emitting elements are formed in a matrix are bundled on the second substrate for each line or a plurality of lines. Is transcribed. Thereafter, the plurality of light emitting elements after being transferred to the second substrate are collectively transferred to the third substrate for each line or every plurality of lines. Thereby, the number of times of transfer can be greatly reduced as compared with the case where the light emitting elements are mounted one by one on a circuit board or the like.

  Here, in each of the steps described above, one line or a plurality of lines of light emitting elements may be transferred from one end of the substrate to the other end at equal intervals, or may be transferred at unequal intervals. Good.

The mounting substrate of the present invention is provided with a plurality of light emitting elements on a fourth substrate. The plurality of light emitting elements are mounted on the fourth substrate through the following steps.
(B1) A step of transferring a plurality of light emitting elements included in a predetermined region of the fifth substrate on which the plurality of light emitting elements are formed in a matrix to the sixth substrate in a lump on a line or a plurality of lines (B2) A step of transferring a plurality of light emitting elements after being transferred to the sixth substrate to the fourth substrate in a lump for each line or a plurality of lines.

The display device of the present invention includes a mounting substrate having a plurality of light emitting elements and a drive IC for driving the plurality of light emitting elements. The plurality of light emitting elements are mounted on a mounting substrate through the following steps.
(C1) A step of collectively transferring a plurality of light emitting elements included in a predetermined region of the fifth substrate on which the plurality of light emitting elements are formed in a matrix to the sixth substrate for each line or a plurality of lines (C2) A step of transferring a plurality of light emitting elements after being transferred to the sixth substrate to the mounting substrate in a lump for each line or a plurality of lines.

  In the mounting substrate and the display device of the present invention, a plurality of light emitting elements included in a predetermined region of the fifth substrate in which the plurality of light emitting elements are formed in a matrix are collectively placed on the sixth substrate for each line or a plurality of lines. Transcribed. Thereafter, the light-emitting elements that have been transferred to the sixth substrate are collectively transferred to the mounting substrate for each line or a plurality of lines. Thereby, the number of times of transfer can be greatly reduced as compared with the case where the light emitting elements are mounted one by one on a circuit board or the like.

  According to the method for manufacturing a mounting substrate of the present invention, a plurality of light emitting elements included in a predetermined region of the first substrate in which a plurality of light emitting elements are formed in a matrix are placed on the second substrate for each line or every plurality of lines. After the batch transfer, the plurality of light emitting elements after being transferred to the second substrate are collectively transferred to the third substrate for each line or every plurality of lines. Thereby, productivity can be improved compared with the case where a light emitting element is mounted in a circuit board etc. one by one.

  In the method for manufacturing a mounting board of the present invention, one line or a plurality of lines of light emitting elements are transferred from one end of the board to the other end at equal intervals, or transferred at unequal intervals. Thus, when the plurality of light emitting elements after being transferred to the third substrate have a positional relationship different from the positional relationship on the first substrate, the light emitting elements after the transfer are emitted without reducing the productivity. The in-plane color unevenness that can occur in the emitted light can be reduced.

  According to the mounting substrate and the display device of the present invention, a plurality of light-emitting elements included in a predetermined region of the fifth substrate in which a plurality of light-emitting elements are formed in a matrix are collectively placed on the sixth substrate for each line or a plurality of lines. After the transfer, the light-emitting elements that have been transferred to the sixth substrate are collectively transferred to the mounting substrate for each line or a plurality of lines. Thereby, productivity can be improved compared with the case where a light emitting element is mounted in a circuit board etc. one by one.

1 is a perspective view of a display device according to an embodiment of the present invention. FIG. 2 is a top view of the image display area in FIG. 1. It is a schematic diagram for demonstrating an example of the manufacturing process of the display panel of FIG. FIG. 12 is a schematic diagram for explaining another example of the manufacturing process of the display panel of FIG. 1. It is a schematic diagram for demonstrating the other example of the manufacturing process of the display panel of FIG. It is a schematic diagram for demonstrating the process following FIGS. FIG. 7 is a schematic diagram of a layout of a display pixel after undergoing the process of FIG. 6.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. The description will be given in the following order.

1. Configuration of display device
Display panel, drive IC
2. 2. Manufacturing method of display panel 3. Operation and effect of display device Modified example

  FIG. 1 is a perspective view showing an example of a schematic configuration of a display device 1 (light emitting device) according to an embodiment of the present invention. The display device 1 according to the present embodiment is a so-called LED display, and uses LEDs as display pixels. For example, as shown in FIG. 1, the display device 1 includes a display panel 10 (fourth substrate, mounting substrate) having a plurality of light emitting elements 12 and a drive IC 20.

[Display panel 10]
The display panel 10 has an image display area 10A and an annular frame area 10B surrounding the image display area 10A in one plane. In the image display area 10A, for example, a plurality of data wirings (not shown) are formed extending in the vertical direction, and further, for example, a plurality of scanning wirings (not shown) intersect with the data wirings. It extends in a direction (for example, a horizontal direction). The data lines and the scan lines intersect (orthogonal) with each other when viewed from the normal direction of the substrate 10 in the image display region 10A. For example, display pixels 11 as shown in FIG. 2 are provided at the intersections between the data lines and the scan lines, and a plurality of display pixels 11 are arranged in a grid pattern in the image display area 10A. FIG. 2 shows an example of the upper surface configuration of the image display area 10A.

  One or more light emitting elements 12 are mounted on the display pixel 11. For example, as shown in FIG. 2, three light emitting elements 12R, 12G, and 12B are mounted on the display pixel 11, and one display pixel 11 is configured by these three light emitting elements 12R, 12G, and 12B. Yes. For example, the display pixels 11 are arranged at a pitch P1 in the horizontal direction and at a pitch P2 in the vertical direction.

  The light emitting element 12R is an LED element that outputs red light, the light emitting element 12G is an LED element that outputs green light, and the light emitting element 12B is an LED element that outputs blue light. The light emitting elements 12R, 12G, and 12B are provided with a pair of electrodes (not shown) for injecting current into the light emitting elements 12R, 12G, and 12B, and one electrode is electrically connected to the data wiring. The other electrode is electrically connected to the scan wiring.

[Drive IC 20]
The drive IC 20 has, for example, two drive ICs 20A and 20B as shown in FIG. The driving IC 20A is a data driver that drives the data wiring connected to the display pixel 11, and is, for example, an elongated bar-shaped chip as shown in FIG. The drive IC 20B is a scan driver that drives the scan wiring connected to the display pixel 11, and is, for example, an elongated bar-shaped chip as shown in FIG.

[Method for Manufacturing Display Panel 10]
Next, an example of a method for manufacturing the display panel 10 of the present embodiment will be described.

  First, a plurality of light emitting elements (12R, 12G, or 12B) are formed in a lattice pattern on one surface of the wafer 100 (first substrate, fifth substrate). As a method for forming a plurality of light emitting elements, for example, the following variations can be considered. Hereinafter, the light emitting element 12 is used as a general term for the light emitting elements 12R, 12G, and 12B.

  (Part 1) As shown in FIG. 3, three types of light emitting elements 12R, 12G, and 12B are formed in a line in one direction for each type on one wafer 100, and intersect with the one direction. It forms periodically in the direction.

  (No. 2) As shown in FIG. 4A, two kinds of light emitting elements (for example, 12R, 12G) out of three kinds of light emitting elements 12R, 12G, and 12B are arranged on a single wafer 100 for each kind. And in a direction intersecting with the one direction, it is formed periodically. 4B, the remaining one type of light emitting elements (for example, 12B) among the three types of light emitting elements 12R, 12G, and 12B is formed on another wafer 100 in a lattice shape.

  (Part 3) As shown in FIGS. 5A, 5B, and 5C, three types of light emitting elements 12R, 12G, and 12B are formed in a grid pattern on separate wafers 100 for each type.

  Next, an area (effective pixel area 100A) in which various characteristics do not vary greatly is selected from the plurality of light emitting elements 12 formed on the wafer 100. Subsequently, the plurality of light emitting elements 12 included in the effective pixel region 100A are transferred to the transfer substrate 200 (second substrate, sixth substrate) in a lump for each line or a plurality of lines.

  At this time, the light emitting elements 12 of one line or a plurality of lines may be transferred at regular intervals from one end of the transfer substrate 200 to the other end, or may be transferred at irregular intervals. As a result, the plurality of light emitting elements 12 after being transferred to the transfer substrate 200 may have the same positional relationship as that on the wafer 100, or may have a different positional relationship.

  In the above process, the light emitting element 12 can be transferred to the transfer substrate 200 by laser transfer. For example, as shown in FIG. 6A, the band-shaped laser light L1 is irradiated to the light emitting elements 12 of one line or plural lines included in the effective pixel region 100A. At this time, it is preferable to move the wafer 100 and the transfer substrate 200 at a predetermined pitch in directions opposite to each other with the position of the light source (not shown) of the laser light L1 fixed (the white arrow in the figure). reference). As a result, as shown in FIG. 7A, the irradiated one or more lines of the light emitting elements 12 are collectively transferred to the transfer substrate 200. At this time, the plurality of light emitting elements 12 after being transferred to the transfer substrate 200 are arranged at a pitch equal to the pitch on the wafer 100 in a direction parallel to the extending direction of the laser light L, and the extending of the laser light L. They are arranged at a predetermined pitch P1 in a direction orthogonal to the current direction.

  Here, when the previous step is the above (1), the direction is parallel to the periodic arrangement direction on the wafer 100 or in the direction intersecting (orthogonal) with the periodic arrangement direction on the wafer 100. The extending strip-shaped laser light L is irradiated to the effective pixel region 100A. When the previous process is the above (2), the direction parallel to the periodic arrangement direction on the wafer 100 on which two types of light emitting elements are formed or the periodic arrangement direction on the wafer 100 The effective pixel region 100 </ b> A is irradiated with a strip-shaped laser beam L extending in a direction intersecting (orthogonal) with. Further, the effective pixel region 100A is irradiated with a strip-shaped laser beam L extending in a direction parallel to one arrangement direction on the wafer 100 on which the remaining one type of light emitting element is formed. If the previous step is the above (No. 3), the effective pixel region 100A is irradiated with a strip-shaped laser beam L extending in a direction parallel to one arrangement direction on the wafer 100.

  Next, the plurality of light emitting elements 12 after being transferred to the transfer substrate 200 are collectively transferred to the transfer substrate 300 (third substrate) for each line or every plurality of lines. The transfer substrate 300 corresponds to the display panel 10 described above, for example. At this time, one line or a plurality of lines of light emitting elements 12 may be transferred to the transfer substrate 300 at equal intervals, or may be transferred randomly.

  At this time, the light emitting elements 12 of one line or a plurality of lines may be transferred at regular intervals from one end of the transfer substrate 300 to the other end, or may be transferred at irregular intervals. In addition, when the light emitting elements 12 of one line or a plurality of lines are transferred to the transfer substrate 200 at equal intervals in the previous process, the light emitting elements 12 of one line or a plurality of lines are transferred to the transfer substrate 300 at equal intervals in this process. It may be transferred or transferred at unequal intervals. Further, when one line or a plurality of lines of light emitting elements 12 are transferred to the transfer substrate 200 at unequal intervals in the previous step, in this step, one line or a plurality of lines of light emitting elements 12 are transferred at equal intervals. Or may be transferred at unequal intervals. As a result of these steps, the plurality of light emitting elements 12 after being transferred to the transfer substrate 300 may have the same positional relationship as that on the wafer 100 or may have a different positional relationship. .

  In the above process, the light emitting element 12 can be transferred to the transfer substrate 300 by laser transfer. For example, as shown in FIG. 6B, one or more lines of the light emitting elements 12 after being transferred to the transfer substrate 200 are irradiated with the belt-shaped laser light L2. At this time, it is preferable to move the transfer substrate 200 and the transfer substrate 300 at a predetermined pitch in directions opposite to each other with the position of the light source (not shown) of the laser light L2 fixed (the white in the drawing). See arrow). As a result, as shown in FIG. 7B, the irradiated one or more lines of the light emitting elements 12 are collectively transferred to the transfer substrate 300. At this time, the plurality of light emitting elements 12 after being transferred to the transfer substrate 300 are arranged at a predetermined pitch P1 in a direction parallel to the extending direction of the laser light L and orthogonal to the extending direction of the laser light L. Are arranged at a predetermined pitch P2 in the direction of

  Here, even if the previous step is any of the above (Part 1), (Part 2), and (Part 3), it extends in a direction orthogonal to the direction in which the transfer substrate 200 is densely arranged. The transfer substrate 200 is irradiated with a strip-shaped laser beam L.

[Operation / Effect of Display Device 1]
In the present embodiment, the display pixel 11 is driven (simple matrix drive) by data lines and scan lines arranged in a simple matrix. Thus, current is sequentially supplied to the display pixels 11 provided at the intersections between the data lines and the scan lines, and an image is displayed in the image display area 10A.

  In the present embodiment, in the manufacturing process, the plurality of light emitting elements 12 included in the effective pixel region 100A of the wafer 100 in which the plurality of light emitting elements 12 are formed in a matrix shape are collectively transferred for each line or a plurality of lines. Transferred to the substrate 200. Thereafter, the plurality of light emitting elements 12 after being transferred to the transfer substrate 200 are collectively transferred to the transfer substrate 300 for each line or every plurality of lines. Thereby, compared with the case where the light emitting element 12 is mounted in a circuit board etc. one by one, the frequency | count of transcription | transfer can be reduced significantly and productivity can be improved.

  By the way, when the collective thinning transfer is performed in which the light emitting elements 12 arranged in a matrix on the wafer 100 are thinned and transferred at a pitch equal to the pixel pitch of the display panel 10, color unevenness may occur. This uneven color is caused by a slight difference in the structure of the light emitting element 12 depending on the position on the wafer 100 due to, for example, uneven gas flow on the wafer 100 in the manufacturing process. .

  Therefore, for example, a method of randomly transferring the light emitting elements 12 to the transfer substrates 200 and 300 one by one instead of performing collective thinning transfer is conceivable. However, in this method, for example, when producing a large display device in which the number of light emitting elements 12 mounted on one display panel 10 reaches a level of several million, transfer is performed several million times. This is necessary and productivity is significantly reduced.

  On the other hand, in the present embodiment, one line or a plurality of lines of light emitting elements 12 are transferred from one end portion of the transfer substrate 200 to the other end portion at equal intervals, or transferred at unequal intervals. Thus, when the plurality of light emitting elements 12 after being transferred to the transfer substrate 300 have a positional relationship different from the positional relationship on the wafer 100, the light emitting elements 12 after the transfer are emitted without reducing productivity. In-plane color unevenness that can occur in light can be reduced. In the present embodiment, the light-emitting elements 12 of one line or a plurality of lines are transferred at an equal interval from one end portion of the transfer substrate 300 to the other end portion, or transferred at unequal intervals. Thus, even when the plurality of light emitting elements 12 after being transferred to the transfer substrate 300 have a positional relationship different from the positional relationship on the wafer 100, the light emitting elements 12 after the transfer are emitted without reducing productivity. In-plane color unevenness that can occur in light can be reduced.

  While the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment, and various modifications can be made.

  For example, in the above-described embodiment, the case where the present invention is applied to an LED display has been specifically described. However, the present invention can of course be applied to other displays. In the above embodiment, the case where the present invention is applied to a simple matrix drive type display has been specifically described. However, the present invention can also be applied to an active matrix drive type display.

  DESCRIPTION OF SYMBOLS 1 ... Display apparatus, 10 ... Display panel, 10A ... Image display area, 10B ... Frame area, 11 ... Display pixel, 12, 12R, 12G, 12B ... Light emitting element, 100 ... Wafer, 200, 300 ... Transfer substrate, 15 ... Substrate, 16 ... interlayer insulating film, 17 ... via, 18, 19, 22 ... connection pad, 20, 20A, 20B ... driver IC, 21 ... semiconductor chip, 23 ... bump, 30 ... anisotropic conductive film, D1 ... width , P1, P2, P3, P4... Pitch.

Claims (6)

A first step of collectively transferring a plurality of light emitting elements included in a predetermined region of the first substrate in which the plurality of light emitting elements are formed in a matrix to the second substrate for each line or a plurality of lines;
And a second step of collectively transferring the plurality of light emitting elements after being transferred to the second substrate to the third substrate for each line or every plurality of lines. In the first step, the one or more lines of light emitting elements are transferred at equal intervals from one end of the second substrate to the other end,
The manufacturing method of the mounting substrate according to claim 1, wherein in the second step, the light emitting elements of the one line or the plurality of lines are transferred at regular intervals from one end portion of the third substrate to the other end portion. In the first step, the one or more lines of light emitting elements are transferred at unequal intervals from one end of the second substrate to the other end,
The manufacturing method of the mounting substrate according to claim 1, wherein in the second step, the light emitting elements of the one line or the plurality of lines are transferred at unequal intervals from one end of the third substrate to the other end. . In the first step, the plurality of light emitting elements after being transferred to the second substrate are included in a predetermined region of the first substrate so as to have a positional relationship different from the positional relationship on the first substrate. Transferring a plurality of light emitting elements to the second substrate;
In the second step, the plurality of light-emitting elements that have been transferred to the third substrate are transferred to the second substrate so that the plurality of light-emitting elements have a different positional relationship from the positional relationship on the second substrate. The manufacturing method of the mounting substrate according to claim 1, wherein the light emitting element is transferred to the third substrate. A plurality of light emitting elements are provided on the fourth substrate,
The plurality of light emitting elements are mounted on the fourth substrate through the following steps.
A step of transferring a plurality of light emitting elements included in a predetermined region of the fifth substrate, in which the plurality of light emitting elements are formed in a matrix, to the sixth substrate in a lump for each line or a plurality of lines; A step of transferring a plurality of light-emitting elements after the transfer to the fourth substrate in a lump for each line or a plurality of lines. A mounting substrate having a plurality of light emitting elements and a driving IC for driving the plurality of light emitting elements;
The plurality of light emitting elements are mounted on the mounting substrate through the following steps.
A step of transferring a plurality of light emitting elements included in a predetermined region of the fifth substrate, in which the plurality of light emitting elements are formed in a matrix, to the sixth substrate in a lump for each line or a plurality of lines; A step of transferring a plurality of light-emitting elements after the transfer onto the mounting substrate in a lump for each line or a plurality of lines;

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