JP6550342B2 - Light emitting element unit, exposure apparatus, image forming apparatus, and method of manufacturing light emitting element unit - Google Patents

Description

  The present invention relates to a light emitting element unit, an exposure apparatus, an image forming apparatus, and a method of manufacturing the light emitting element unit.

  An electrophotographic image forming apparatus (e.g., a printer, a copier, a facsimile machine, a multifunction machine, etc.) irradiates uniformly charged photosensitive drums with light corresponding to image data to print on the photosensitive drums. An exposure device for forming an electrostatic latent image is provided. The exposure apparatus has a light emitting element unit in which a semiconductor composite device is mounted on a printed wiring board. Patent Document 1 describes an LED unit (light emitting element unit) having a printed wiring board and a plurality of composite chips (semiconductor composite devices) provided on the wiring board.

JP, 2007-81081, A (For example, paragraph 0031, FIG. 3)

  However, in the conventional light emitting element unit described above, since the bonding pad for connecting one end of the bonding wire is formed on the side surface of the semiconductor substrate to electrically connect the semiconductor substrate and the printed wiring board, the manufacturing cost increases. Had the problem of

  The present invention has been made to solve the problems of the prior art, and provides a light emitting element unit, an exposure apparatus, an image forming apparatus, and a method of manufacturing the light emitting element unit that can reduce the manufacturing cost. With the goal.

A light emitting element unit according to the present invention includes a semiconductor substrate having a first surface and a second surface adjacent to each other and intersecting each other, a connecting portion formed on the first surface, and a light emitting element formed on the first surface. And a bonding wire having an end ball and a wire portion extending from the end ball, wherein the end ball intersects a first portion formed on the second surface and the first portion . And a second portion extending over the connection portion of the first surface via the first surface and an end of the second surface .

A method of manufacturing a light emitting device unit according to the present invention comprises the steps of: forming a connecting portion on the first surface of a semiconductor substrate having a first surface and a second surface adjacent to each other and intersecting ; and a light emitting device on the first surface Bonding the wire with the end ball and the wire portion extending from the end ball, the end ball crossing the first portion formed on the second surface and the first portion Attaching the first surface and the second portion extending over the end of the second surface to the connection portion of the first surface. Do.

  According to the light emitting element unit, the exposure apparatus, the image forming apparatus, and the method of manufacturing the light emitting element unit according to the present invention, the effect of reducing the manufacturing cost is achieved.

It is a perspective view which shows schematic structure of the LED unit which concerns on Embodiment 1 of this invention. (A) is an upper surface enlarged view (figure seen in -z direction of FIG. 1) of the LED unit which concerns on Embodiment 1, (b) is a part shown by the II broken line in FIG. 2 (a) 2 (c) is an enlarged view of the end ball portion as viewed in the -x direction of FIG. 2 (a). FIGS. 7A to 7C are cross-sectional views showing a method of manufacturing the LED unit according to Embodiment 1. FIGS. 5 is a perspective view showing a schematic configuration of an LED unit according to a comparative example of Embodiment 1. FIG. It is a perspective view which shows schematic structure of the LED unit which concerns on Embodiment 2 of this invention. FIG. 6A is an enlarged top view of the LED unit according to Embodiment 2 (an enlarged view seen in the −z direction in FIG. 4), and FIG. 6B is a broken line I-I in FIG. FIG. 18 is a cross-sectional view of a portion, showing the cross-sectional shape of the side surface mark in the basic example of the LED unit according to Embodiment 2. (C) to (e) are cross-sectional views of a portion indicated by a broken line II showing the cross-sectional shape of the side surface mark of the modification of the LED unit according to the second embodiment. (A) to (f) are cross-sectional views showing manufacturing steps of the LED unit according to the second embodiment. (A) to (c) are plan views seen from the wafer surface. (D) to (f) are cross-sectional views of a portion indicated by a broken line II in FIGS. 6 (a) to 6 (c). It is a perspective view which shows schematic structure of the LED unit which concerns on Embodiment 3 of this invention. (A) is an upper surface enlarged view (enlarged view seen in the -z direction of FIG. 7) of the LED unit according to Embodiment 3, and (b) is indicated by a broken line I-I in FIG. It is sectional drawing of a part. (C) is an enlarged view of the end ball portion seen in the −x direction of FIG. 9 (a). FIG. 9D is a cross-sectional view of a portion indicated by a broken line II-II in FIG. 9A and shows a basic example of the third embodiment. FIG. 9E is a cross-sectional view of a portion indicated by a broken line II-II in FIG. 9A according to a modification of the third embodiment. It is a figure which shows schematic structure of the exposure apparatus which concerns on Embodiment 4 of this invention. FIG. 10 is a diagram showing a schematic configuration of an image forming apparatus according to Embodiment 5 of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The figure shows the coordinate axes of the xyz Cartesian coordinate system. The x-axis is a coordinate axis in the lateral direction of the LED unit. The y-axis is the coordinate axis in the longitudinal direction of the LED unit. The z axis is a coordinate axis in the height direction of the LED unit.

<< 1 >> Embodiment 1
<< 1-1 >> Configuration The configuration of the LED unit 10 (light emitting element unit) according to the present embodiment will be described with reference to FIG. FIG. 1 is a perspective view showing a schematic configuration of an LED unit 10 according to Embodiment 1 of the present invention. As shown in FIG. 1, the LED unit 10 includes a semiconductor substrate 20 having a first surface 20A and a second surface 20B adjacent to each other, a connecting portion 23 formed on the first surface 20A of the semiconductor substrate 20, and a light emitting element 22 and a bonding wire 30 having a termination ball 31 and a wire portion 32 extending from the termination ball 31. The LED unit 10 may have a printed wiring board 40 as a mounting board. The integrated circuit portion 21 may be formed on the first surface 20 </ b> A of the semiconductor substrate 20. In the following description, one in which the integrated circuit portion 21, the light emitting element 22, and the connection portion 23 are formed on the semiconductor substrate 20 is referred to as a composite chip 70. Further, the term “end ball 31 of bonding wire 30” (or simply “end ball 31”) refers to the end ball 31 which is the end of the bonding wire 30 on the semiconductor substrate 20 side.

  The LED unit 10 is a light emitting element unit using the light emitting element 22 in which the composite chip 70 in which the light emitting element 22 is formed on the semiconductor substrate 20 is mounted on the printed wiring board 40 (mounting substrate) as a light source. The LED unit 10 according to the first embodiment is a parallel LED unit in which the direction in which the light emitting element 22 emits light is parallel to the mounting surface of the printed wiring board 40 (mounting substrate). However, “parallel” as used herein includes substantially parallel.

  The light emitting element 22 is, for example, a light emitting diode (LED). The printed wiring board 40 is mainly made of, for example, any of insulators such as glass, resin, and ceramic, metal, and semiconductor. On the printed wiring board 40, in addition to the composite chip 70, PCB (printed circuit board) pads 41 (shown in FIG. 2A) which are connection pads (electrodes) to which one end of the bonding wire 30 is connected are shown. It is provided.

  Furthermore, on the printed wiring board 40, connector terminals for inputting external signals and power, capacitors and resistors for reducing signal noise and reflection, voltage dividing resistors for determining current for driving, Parts necessary for driving may be mounted such as a regulator IC and a memory for storing data for current correction. They are not described in FIG.

  As shown in FIG. 1, on the upper surface of the printed wiring board 40 (the surface facing the + z direction in FIG. 1), a plurality of composite chips 70 are arranged in a line at equal intervals in the longitudinal direction (y direction). Ru. However, the plurality of composite chips 70 may not be arranged at equal intervals. Further, the number of rows of the plurality of composite chips 70 is not limited to one. A bonding wire 30 is stretched and electrically connected between the PCB pad 41 provided on the printed wiring board 40 and the composite chip 70.

  In FIG. 1, a side surface of the semiconductor substrate 20 facing the + x direction is referred to as a first surface 20A. The upper surface (the surface facing the + z direction in FIG. 1) of the semiconductor substrate 20 is referred to as a second surface 20B. The lower surface (the surface facing in the −z direction in FIG. 1) of the semiconductor substrate 20 is referred to as a third surface 20C. The semiconductor substrate 20 is bonded onto the printed wiring board 40 by adhering the third surface 20C to the upper surface (the surface facing the + z direction in FIG. 1) of the printed wiring board 40 with an adhesive such as insulating paste or conductive paste. Implemented.

  The integrated circuit portion 21 is formed on the first surface 20 A of the semiconductor substrate 20, and the plurality of light emitting elements 22 are joined via the interlayer insulating film 24. Further, at the upper end portion of the first surface 20A of the composite chip 70, a connection portion 23 for electrically connecting the bonding wire 30 and the integrated circuit portion 21 is formed. Electrical connection members (not shown) are provided between the integrated circuit portion 21 and the light emitting element 22 and the connection portion 23, and these are electrically connected.

  FIG. 2A is an enlarged top view of the LED unit 10 (viewed in the −z direction in FIG. 1). As shown in FIG. 2A, the end of the bonding wire 30 on the printed wiring board 40 side is connected to a PCB pad provided on the printed wiring board 40. On the other hand, the end of the bonding wire 30 on the composite chip 70 side is connected to the second surface 20 B of the semiconductor substrate 20 via the terminal ball 31.

  FIG. 2 (b) is a cross-sectional view of a portion indicated by a broken line II in FIG. 2 (a). As shown in FIG. 2B, the end ball 31 is formed of a first portion 311 formed on the second surface 20B of the semiconductor substrate 20 and a first surface 20A of the semiconductor substrate 20 from the first portion 311. And a second portion 312 extending onto the connection 23 of the Thus, the second portion 312 which is a part of the end ball 31 is from the end of the second surface 20B of the semiconductor substrate 20 (the side where the second surface 20B and the first surface 20A intersect) in the x direction It is formed to protrude.

  FIG.2 (c) is an enlarged view of the termination | terminus ball 31 part seen in the-x direction of Fig.2 (a). As shown in FIG. 2C, the second portion 312 of the terminal ball 31 protrudes on the first surface 20A of the semiconductor substrate 20 and is formed on the upper end portion of the semiconductor substrate 20 on the first surface 20A. It is in contact with a part of the connection 23. Thus, the bonding wire 30 and the connection portion 23 are electrically connected.

<< 1-2 >> Method of Manufacturing LED Unit Hereinafter, an example of a method of manufacturing the LED unit 10 (in particular, a method of manufacturing the bonding wire 30 and the terminal ball 31) will be described with reference to FIGS. 3 (a) to 3 (c). . In a method of manufacturing a light emitting element unit 10, a step of forming a connection portion on a first surface of a semiconductor substrate having a first surface and a second surface adjacent to each other, a step of disposing a light emitting device on the first surface, and an end ball And a bonding wire having a wire portion extending from the end ball, the end ball having a first portion formed on the second surface, and a second portion extending from the first portion to the connection portion on the first surface Attaching to include the part of.

  FIGS. 3A to 3C are cross-sectional views showing a method of manufacturing the LED unit 10 according to the first embodiment. As shown in FIG. 3A, the bonding wire 30 is inserted into the capillary 201, an electric torch (not shown) is made to face the tip of the capillary 201, and the tip of the bonding wire 30 is discharged by discharging with the bonding wire 30. It is heated and melted to form an initial ball 203.

  Next, as shown in FIG. 3B, the capillary 201 is lowered to press and bond the initial ball 203 onto the second surface 20B so as to protrude from the second surface 20B of the semiconductor substrate 20 in the x direction. At this time, ultrasonic vibration is applied through the capillary 201, and the LED unit 10 and the composite chip 70 are heated by the heater block (not shown), so that the initial ball 203 is thermocompression-bonded and deformed, and the second surface 20B and the semiconductor substrate 20 (The side where the first surface 20A intersects with the second surface 20B) and the connecting portion 23 on the first surface 20A.

  Next, as shown in FIG. 3C, the capillary 201 draws a predetermined trajectory and moves onto the PCB pad 41, ultrasonic vibration is applied through the capillary 201, and the PCB pad 41 is a heater block. The bonding wires 30 are stitch-bonded because they are heated by Further, by raising the cut clamp 202 while clamping the bonding wire 30, the bonding wire 30 is cut and wiring is completed.

<< 1-3 >> Comparative Example FIG. 4 is a perspective view showing a schematic configuration of an LED unit (light emitting element unit) 400 according to a comparative example of the first embodiment. As shown in FIG. 4, in the LED unit 400 according to the comparative example, the bonding pad 403 is formed on the second surface 402 of the semiconductor substrate 401. However, in the LED unit 400 according to the comparative example, since the manufacturing process of the bonding pad 403 is necessary, it is difficult to reduce the manufacturing cost.

<< 1-4 >> Effects According to the LED unit 10 of the first embodiment, the end ball 31 of the bonding wire 30 is formed of the first portion 311 formed on the second surface 20B of the semiconductor substrate 20, and the first And a second portion 312 extending from the portion 311 of the first surface 20A of the semiconductor substrate 20 to the connection portion 23 of the first surface 20A of the semiconductor substrate 20. The wire portion 32 of the is electrically connected. Thereby, the semiconductor substrate 20 and the printed wiring board 40 can be electrically connected without providing the bonding pad on the second surface 20B of the semiconductor substrate 20. Therefore, the manufacturing process of a bonding pad can be made unnecessary, and the manufacturing cost of LED unit 10 can be reduced compared with LED unit 400 concerning a comparative example.

  Specifically, in the case of forming a bonding pad, a hole is formed from the surface side of semiconductor substrate 20 in the manufacturing process of semiconductor substrate 20, and a metal film is formed on the hole to perform patterning. Although the formation process was required, this can be made unnecessary.

  Moreover, when forming a bonding pad, although it was necessary to perform blade dicing at the time of chip formation, this can be made unnecessary. Therefore, it is possible to suppress the decrease in the number of composite chips 70 taken out per silicon wafer by the area of the cutting edge of the blade dicing.

<< 2 >> Second Embodiment
<< 2-1 >> Configuration FIG. 5 is a perspective view showing a schematic configuration of an LED unit 10A according to Embodiment 2 of the present invention. As shown in FIG. 5, in the LED unit 10A according to the second embodiment, side marks 50 are formed at both ends of the second surface 20B of the semiconductor substrate 20. Except for this point, the second embodiment is the same as the first embodiment. Therefore, in the description of the second embodiment, differences from the first embodiment will be mainly described. In FIG. 5, components that are the same as or correspond to components shown in FIG. 1 are given the same reference numerals as in FIG. 1.

  FIG. 6A is an enlarged top view of the LED unit 10A according to the second embodiment (an enlarged view in the −z direction in FIG. 5). As shown in FIG. 6A, the side surface mark 50 is formed on the second surface 20B of the semiconductor substrate 20 mounted on the printed wiring board 40 of the LED unit 10A. The side surface marks 50 are alignment marks used when the semiconductor substrate 20 is die-bonded to the printed wiring board 40. FIG. 6B is a cross-sectional view of a portion indicated by a broken line I-I in FIG. 6A, and shows a cross-sectional shape of a side surface mark in a basic example of the LED unit 10A according to the second embodiment. As shown in FIG. 6B, the cross-sectional shape of the side surface mark is a rectangular concave shape.

  FIGS. 6C, 6D, and 6E are cross-sectional views of a portion indicated by a broken line I-I showing the cross-sectional shapes of the side surface marks 51, 52, 53 of the modification of the second embodiment. In the basic example of the second embodiment, the cross-sectional shape of the side surface mark is a rectangular concave shape, but the cross-sectional shape of the side surface mark is, for example, the shape shown in FIG. 6 (c), (d), (e). be able to. In FIG. 6C, the cross-sectional shape of the side surface mark 51 is a rectangular convex shape. In FIG. 6D, the cross-sectional shape of the side surface mark 52 is a V-shaped concave shape. In FIG. 6E, the cross-sectional shape of the side surface mark 53 is a V-shaped convex shape. The cross-sectional shape of the side surface mark is not limited to the shape shown in FIGS. 6B to 6E, and may be another shape as long as it can be recognized as an alignment mark.

<< 2-2 >> Manufacturing Method A manufacturing process of the side surface mark 50 of the LED unit 10A according to the second embodiment of the present invention will be described with reference to FIGS. 7 (a) to 7 (f). FIGS. 7A to 7F are cross-sectional views showing manufacturing steps of the LED unit 10A according to the second embodiment. FIGS. 7A to 7C are plan views as viewed from the wafer surface. Cross-sectional views of a portion indicated by a broken line II in FIGS. 7A to 7C are shown in FIGS. 7D to 7F.

  FIGS. 7A and 7D show steps of forming the integrated circuit portion 21 and the light emitting element 22 in the LED unit 10A according to the second embodiment. As shown in FIGS. 7A and 7D, after the integrated circuit portion 21 is formed on a semiconductor substrate 20 (for example, made of silicon), the light emitting element 22 is bonded to a predetermined position to form an interlayer. The connection portion 23 is formed by patterning the insulating film 24 and the metal film by a known film formation technique, photolithography technique and dry etching technique, and the integrated circuit portion 21, the light emitting element 22 and the connection portion 23 are electrically Connect.

  FIGS. 7B and 7E show a process of forming the side surface mark 50 and the dividing groove 80 in the LED unit 10A according to the second embodiment. As shown in FIGS. 7B and 7E, after the integrated circuit portion 21 and the light emitting element 22 are formed, the dividing grooves 80 and the side marks 50 are formed on the semiconductor substrate 20 by known photolithography technology and dry etching technology. Form By this process, the dividing groove 80 and the side surface mark 50 can be formed simultaneously.

  FIGS. 7C and 7F show steps of chip division in the LED unit 10A according to the second embodiment. As shown in FIGS. 7 (c) and 7 (f), by performing chip division by polishing with a known grinder from the back side of the wafer, composite chips 70 with a plurality of side marks 50 are obtained in the wafer. 7C and 7F, the wafer surface of the composite chip 70 with side surface marks is the first surface 20A, the side surface on the connection portion 23 side is the second surface 20B, and the opposite side surface is the third surface. It is a face 20C.

  In FIGS. 7A to 7F, the manufacturing process of the side surface mark 50 having a rectangular concave shape shown in FIG. 6B has been described as a representative example. However, the processes in FIGS. 7B and 7E are described. By changing the shape of patterning, the shapes shown in FIGS. 6 (c) to 6 (e) can be obtained.

<< 2-3 >> Effects The LED unit 10A according to the second embodiment can obtain the same effects as the effects in the first embodiment.

  According to the LED unit 10A according to the second embodiment, by forming the side surface marks 50, 51, 52, 53, alignment by recognition from the second surface 20B side is facilitated, so that the die bonding of the composite chip 70 is performed. Accuracy is improved.

  According to the LED unit 10A according to the second embodiment, the side surface marks 50, 51, 52, 53 can be formed simultaneously with the formation of the dividing groove 80 by the known photolithography technique and the dry etching technique. There is no need to add a process for providing 51, 52, 53. Thereby, the increase in the manufacturing cost of LED unit 10A can be suppressed.

  According to the LED unit 10A according to the second embodiment, the side surface marks 50, 51, 52, 53 can be formed by known photolithography and etching, so the degree of freedom in shape design is high.

  According to the modification of the LED unit 10A according to the second embodiment, the cross sectional shape of the side surface mark 52 is a V-shaped concave shape, and the cross sectional shape of the side surface mark 53 is a V-shaped convex shape. As a result, since a line can be formed at the center of the side surface mark, the accuracy of image recognition can be improved.

<< 3 >> Third Embodiment
<< 3-1 >> Configuration FIG. 8 is a perspective view showing a schematic configuration of an LED unit 10B according to Embodiment 3 of the present invention. As shown in FIG. 8, in the LED unit 10B according to the third embodiment, holding structures 60 for holding the end balls 31 are formed at a plurality of locations on the second surface 20B of the semiconductor substrate 20. Except for this point, the third embodiment is the same as the first embodiment. Therefore, in the description of the third embodiment, differences from the first embodiment will be mainly described. In FIG. 8, components that are the same as or correspond to components shown in FIG. 1 are given the same reference symbols as the reference symbols in FIG. 1.

  FIG. 9A is an enlarged top view (enlarged view seen in the −z direction of FIG. 8) of the LED unit 10B according to the third embodiment shown in FIG. As shown in FIG. 9A, a plurality of holding structures 60 are formed on the second surface 20B of the semiconductor substrate 20 corresponding to the positions of the end balls 31. As shown in FIG. The holding structure 60 is a recess formed by cutting a part of the second surface 20B of the semiconductor substrate 20, and reaches the first surface.

  The holding structure 60 is formed to improve the holding force of the end ball 31. The holding structure 60 can be formed simultaneously with the step of forming the dividing groove 80 by known photolithography technology and dry etching technology. As shown in FIG. 9A, the length L1 of the holding structure 60 in the y direction (the width of the holding structure 60) is shorter than the length L2 of the end ball 31 in the y direction (the diameter of the end ball 31). .

  FIG. 9 (b) is a cross-sectional view of a portion indicated by a broken line I-I in FIG. 9 (a), and FIG. 9 (c) is a portion of the end ball 31 viewed in the -x direction of FIG. It is an enlarged view. FIG. 9 (d) is a cross-sectional view of a portion indicated by a broken line II-II in FIG. 9 (a), and shows a basic example of the third embodiment. FIG. 9E is a cross-sectional view of a portion indicated by a broken line II-II in FIG. 9A according to a modification of the third embodiment.

  As shown in FIGS. 9B and 9C, the terminal ball 31 of the bonding wire 30 is deformed along the internal shape of the holding structure 60, and is held in a state where a part is fitted to the holding structure 60. ing. The end ball includes a first portion 311 formed in the recess of the holding structure 60 and a second portion 312 extending onto the connection 23. As shown in FIG. 9D, the cross-sectional shape of the recess of the holding structure 60 can be a rectangular groove. The terminal ball 31 of the LED unit 10B according to the third embodiment is deformed such that a part thereof conforms to the shape of the recess of the holding structure 60. The holding structure 60, the connection portion 23, and the end ball 31 are positioned and electrically connected at positions where they can be electrically connected.

  FIG. 9E is a cross-sectional view of a portion indicated by a broken line I-I showing the cross-sectional shape of the recess of the holding structure 61 of the modified example of the present embodiment. In the basic example of the third embodiment, the cross-sectional shape of the recess of the holding structure 60 is a rectangular groove shown in FIG. 9D, but the cross-sectional shape of the recess of the holding structure 61 is, for example, FIG. As shown in FIG. 2, the shape can be expanded as the distance from the second surface 20 B of the semiconductor substrate 20 increases. The cross sectional shapes of the holding structures 60 and 61 are not limited to the shapes shown in FIGS. 9D and 9E, and may be any other shape as long as the holding force of the end ball 31 can be improved. Good.

<<3-2> Effects The LED unit 10B according to the third embodiment can obtain the same effects as the effects in the first embodiment.

  According to the LED unit 10B according to the third embodiment, the holding structures 60 and 61 are formed on the second surface 20B of the semiconductor substrate 20. As a result, a part of the end ball 31 is held by the holding structure 60. 61 while being deformed along the inner shape of the holding structures 60, 61. Therefore, the holding force of the end ball 31 is improved.

  According to the LED unit 10B according to the third embodiment, the length L1 (the width of the holding structure 60) of the holding structure 60 in the y direction is equal to the length L2 (the diameter of the ending ball 31) of the end ball 31 Too short. As a result, the end balls 31 are held by the holding structures 60 and 61 in a state where a part of the end balls 31 is fitted into the holding structures 60 and 61. Therefore, the holding force of the end ball 31 is improved.

  According to the LED unit 10B according to the third embodiment, the holding structures 60 and 61 for holding the end ball 31 are formed on the second surface 20B of the semiconductor substrate 20. The holding structures 60 and 61 can be used as alignment marks when the composite chip 70 is die-bonded to the printed wiring board 40. The holding structures 60 and 61 can also be used as alignment marks when wire bonding bonding wires 30 to the second surface 20B of the semiconductor substrate 20. As a result, the accuracy of die bonding of the composite chip 70 and the accuracy of wire bonding of the bonding wire 30 can be improved.

  According to the LED unit 10B according to the third embodiment, the holding structures 60 and 61 can be formed simultaneously with the divided structure forming process by known photolithography and etching, and the process for adding the holding structures 60 and 61 can be added. There is no need to do it. Thereby, the increase in the manufacturing cost of LED unit 10B can be suppressed.

  According to the LED unit 10B according to the third embodiment, the holding structures 60 and 61 can be formed by known photolithography technology and dry etching technology, so that the freedom of shape design is high. For example, by setting the cross-sectional shape of the holding structures 60 and 61 to a shape that becomes wider as the distance from the second surface 20B of the semiconductor substrate 20 increases, the holding force of the end ball can be improved.

<< 4 >> Fourth Embodiment
<< 4-1 >> Configuration FIG. 10 is a view showing a schematic configuration of an exposure apparatus (LED head) 90 including the LED units 10, 10A and 10B according to the first to third embodiments. As shown in FIG. 10, the exposure apparatus 90 includes an LED unit 10, 10A, 10B, a frame member 91 which is a support for supporting the LED unit 10, 10A, 10B, a rod lens array 92, and a rod lens array. And a holder member 93 for holding 92, the rod lens array 92 and the holder member 93 are held by the frame member 91.

  The light emitted from the LED units 10, 10A and 10B is converged by the rod lens array 92, and is exposed on the charged photosensitive drum of the image forming apparatus (not shown) to form an electrostatic latent image.

<4-2> Effects The exposure apparatus 90 according to the fourth embodiment can reduce the manufacturing cost of the exposure apparatus 90 because the LED units 10, 10A, and 10B with reduced manufacturing costs are mounted.

<< 5 >> Fifth Embodiment
<< 5-1 >> Configuration FIG. 11 is a view showing a schematic configuration of an image forming apparatus 100 having an exposure device 90 mounted with the LED units 10, 10A and 10B of the first to third embodiments. The configuration of the image forming apparatus 100 according to the present embodiment will be described with reference to FIG. The image forming apparatus 100 is, for example, an electrophotographic color printer. In the image forming apparatus 100, four independent image forming units 110K, 110Y, 110M, and 110C are disposed along the traveling direction (the direction from the insertion side to the discharge side) of the sheet 101 as the recording medium. .

  The image forming units 110K, 110Y, 110M and 110C respectively form images of black, yellow, magenta and cyan. Note that OHP sheets, envelopes, copying sheets, special sheets, etc. can also be used as recording media.

  The image forming units 110K, 110Y, 110M and 110C include LED heads 111K, 111Y, 111M and 111C as exposure devices, image carriers (for example, photosensitive drums) 112K, 112Y, 112M and 112C, and the photosensitive drums. The chargers (for example, charging rollers) 113K, 113Y, 113M and 113C are provided to charge the surfaces of 112K, 112Y, 112M and 112C uniformly (uniformly). The image forming units 110K, 110Y, 110M, and 110C attach a developer (for example, toner) to the electrostatic latent images formed on the surfaces of the photosensitive drums 112K, 112Y, 112M, and 112C to form a visible image. The developing units 118 K, 118 Y, 118 M, and 118 C, which are developing units that form toner images of respective colors, are provided. The developing devices 118K, 118Y, 118M and 118C are, for example, developing rollers 114K, 114Y, 114M and 114C as developer carriers, and a developer supply member for supplying the developer to the developing rollers 114K, 114Y, 114M and 114C. The toner supply rollers 115K, 115Y, 115M, and 115C are respectively provided as

  The toner supply rollers 115K, 115Y, 115M and 115C are rollers for supplying the toner supplied from the toner cartridge to the developing rollers 114K, 114Y, 114M and 114C. The developing blades 116K, 116Y, 116M, 116C are in contact with the developing rollers 114K, 114Y, 114M, 114C. The developing blades 116K, 116Y, 116M and 116C thin the toner supplied from the toner supply rollers 115K, 115Y, 115M and 115C on the developing rollers 114K, 114Y, 114M and 114C (restrict the thickness of the toner layer) ) Is a restriction member.

  LED heads 111K, 111Y, 111M and 111C, which are exposure devices, are disposed at positions (upper in FIG. 1) facing the photosensitive drums 112K, 112Y, 112M and 112C in the image forming units 110K, 110Y, 110M and 110C. The photosensitive drums 112K, 112Y, 112M, and 112C are disposed to face each other. Hereinafter, the exposure apparatus is also referred to as an LED head.

  The LED heads 111K, 111Y, 111M and 111C expose the photosensitive drums 112K, 112Y, 112M and 112C, respectively, using light according to the image data of black, yellow, magenta and cyan, and the photosensitive drums 112K, 112K, An electrostatic latent image is formed on each of 112Y, 112M and 112C. Transfer rollers 117 K and 117 Y as transfer devices at positions facing the photosensitive drums 112 K, 112 Y, 112 M and 112 C with the conveying belt 130 in between (in FIG. 1, lower than the photosensitive drums 112 K, 112 Y, 112 M and 112 C). , 117M and 117C, respectively.

  The transfer unit includes transfer rollers 117K, 117Y, 117M, and 117C as transfer devices, and a transport belt 130 as a transport member. The transfer rollers 117K, 117Y, 117M, and 117C are disposed to face the photosensitive drums 112K, 112Y, 112M, and 112C via the transport belt 130, and charge the sheet to the opposite polarity to the toner, and the photosensitive drums 112K and 112K, The toner images on 112Y, 112M and 112C are transferred to the sheet.

  Further, the image forming apparatus 100 is provided with a sheet feeding mechanism 120 for feeding sheets to the conveyance belt 130. The sheet feeding mechanism 120 includes a hopping roller 121, a registration roller 122, and a sheet storage cassette 123 as a medium storage portion. The image forming apparatus 100 may further include a sheet color measurement unit 124 that measures the color of the sheet in the sheet storage cassette 123.

  Further, a fixing device 150 is provided on the discharge side of the conveying belt 130. The fixing device 150 has a heating roller 151 and a backup roller 152. The fixing unit 150 is a device that fixes the toner transferred onto the sheet by heating and pressing, and the discharging roller 160, a sheet stacker, and the like are provided on the discharging side.

<< 5-2 >> Operation The operation of the image forming apparatus 100 according to the present embodiment will be described with reference to FIG. First, the sheets 101 in the sheet storage cassette 123 are fed one by one by the hopping roller 121 and are sent to the registration roller 122. Subsequently, the fed sheet 101 is sent from the registration roller 122 to the conveyance belt 130, and is conveyed to the image forming units 110K, 110Y, 110M, and 110C as the conveyance belt 130 travels.

  In the image forming units 110K, 110Y, 110M and 110C, the surfaces of the photosensitive drums 112K, 112Y, 112M and 112C are charged by the charging rollers 113K, 113Y, 113M and 113C and exposed by the LED heads 111K, 111Y, 111M and 111C. And an electrostatic latent image is formed. Toners thinned in layers on the developing rollers 114K, 114Y, 114M and 114C are electrostatically attached to the electrostatic latent images to form toner images of respective colors.

  The toner images of the respective colors are transferred onto the sheet by the transfer rollers 117K, 117Y, 117M and 117C, and a color toner image is formed on the sheet. After transfer, the toner remaining on the photosensitive drums 112K, 112Y, 112M and 112C is removed by a cleaning device (not shown). The sheet on which the color toner image is formed is sent to the fixing unit 150.

  In the fixing unit 150, a color toner image is fixed to the sheet to form a color image. The sheet on which the toner image is formed is nipped by a discharge roller and a pinch roller (not shown) and discharged to a sheet stacker. Through this process, a color image is formed on the sheet.

<< 5-3 >> Effects In the image forming apparatus 100 according to the fifth embodiment, since the exposure device 90 having the LED units 10, 10A and 10B whose manufacturing cost is reduced is mounted, the manufacturing cost of the image forming apparatus 100 can be reduced. It can be reduced.

<< 6 >> Modifications Although the light emitting element unit, the exposure apparatus, and the image forming apparatus according to the present invention have been described in the first to fifth embodiments, the embodiments are combined within the scope of the present invention. In addition, each embodiment can be modified as appropriate.

  Although the light emitting element is described as an LED in the above embodiment, the light emitting element is not limited to an LED, and may be an organic EL, an inorganic EL, or the like. The light emitting element may be one to which a switching function is added, such as a light emitting thyristor or a light emitting transistor.

  In the above embodiment, the optical element mounted on the LED unit has been described as a light emitting element. However, by replacing the light emitting element with a light receiving element, it can be adapted to a line sensor in a scanner unit.

  DESCRIPTION OF SYMBOLS 10, 10A, 10B LED unit, 20 semiconductor substrate, 20A 1st surface, 20B 2nd surface, 20C 3rd surface, 21 integrated circuit part, 22 light emitting element, 23 connection part, 24 interlayer insulation film, 30 bonding wire, 31 End ball, 32 wires, 40 printed circuit boards, 41 PCB pads, 50, 51, 52, 53 side marks, 60, 61 holding structure, 70 composite chips, 80 split grooves, 90 exposure device (LED head), 91 frame Members, 92 rod lens array, 93 holder members, 100 image forming apparatus, 101 recording medium (sheet), 110 K, 110 Y, 110 M, 110 C image forming unit, 111 K, 111 Y, 111 M, 111 C exposure device, 112 K, 112 Y, 112 M, 12C Photosensitive drum (image carrier), 113K, 113Y, 113M, 113C charging roller, 114K, 114Y, 114M, 114C Developer roller (developer carrier), 115K, 115Y, 115M, 115C Supply roller (developer supply member , 116K, 116Y, 116M, 116C developing blade, 117K, 117Y, 117M, 117C transfer roller, 120 sheet feeding mechanism, 121 hopping roller, 122 registration roller, 123 sheet storage cassette, 124 sheet color measuring unit, 130 transport belt , 150 fuser, 151 heating roller, 152 backup roller, 160 discharge roller, 201 capillary, 202 cut clamp, 203 initial ball, 311 first portion, 312 second Portion, 400 LED unit, 401 a semiconductor substrate, 402 a second surface, 403 bonding pad, L1 width of the holding structure, the L2 termination ball diameter, the length of L3 bottom portion, L4 tip portion length of (the opening portion).

Claims (19)

A semiconductor substrate having a first surface and a second surface adjacent to and intersecting with each other;
A connection formed on the first surface;
A light emitting element formed on the first surface;
A bonding wire having a termination ball and a wire portion extending from the termination ball;
Equipped with
The end ball has a first portion formed on the second surface, the first surface intersecting from the first portion, and an end portion of the second surface. What is claimed is: 1. A light emitting element unit comprising: a second portion extending onto a connection portion. The light emitting element unit according to claim 1, wherein the semiconductor substrate has a holding structure for holding the terminal ball on the second surface. The holding structure is a recess reaching the first surface,
The light emitting element unit according to claim 2, wherein the end ball includes the first portion formed in the recess and the second portion extending onto the connection portion. The light emitting element unit according to claim 3, wherein a width of the recess is smaller than a diameter of the end ball. The cross-sectional shape of the said recessed part is a rectangular groove shape. The light emitting element unit of Claim 3 or 4 characterized by the above-mentioned. The cross-sectional shape of the said recessed part is a shape which spreads so that it leaves | separates from the said 2nd surface. The light emitting element unit of Claim 3 or 4 characterized by the above-mentioned. The light emitting element unit according to any one of claims 1 to 6, wherein the semiconductor substrate has a side surface mark formed on the second surface. The light emitting element unit according to claim 7, wherein a cross-sectional shape of the side surface mark is a rectangular concave shape. The light emitting element unit according to claim 7, wherein a cross-sectional shape of the side surface mark is a rectangular convex shape. The light emitting element unit according to claim 7, wherein a cross-sectional shape of the side surface mark is a V-shaped concave shape. The light emitting element unit according to claim 7, wherein a cross-sectional shape of the side surface mark is a V-shaped convex shape. The light emitting element unit according to any one of claims 1 to 11, further comprising an integrated circuit unit disposed on the first surface. The light emitting element unit according to any one of claims 1 to 12, further comprising a mounting substrate on which the semiconductor substrate is mounted. The light emitting element unit according to claim 13, wherein the mounting substrate has an electrode to which an end of the bonding wire opposite to the end ball is connected. The semiconductor substrate has a third surface which is a surface opposite to the second surface,
The light emitting element unit according to claim 13, wherein the semiconductor substrate is mounted such that the third surface is in contact with the mounting substrate. The light emitting element unit according to any one of claims 1 to 15, wherein the first surface and the second surface are surfaces orthogonal to each other. The light emitting element unit according to any one of claims 1 to 16;
A support for supporting the light emitting element unit;
A rod lens array for guiding light from the light emitting element;
An exposure apparatus comprising: An exposure apparatus according to claim 17;
An image carrier for irradiating the charged surface with light by the exposure device to form an electrostatic latent image;
A developing unit for developing the electrostatic latent image;
An image forming apparatus comprising: Forming a connecting portion on the first surface of the semiconductor substrate having a first surface and a second surface adjacent to and crossing each other;
Disposing a light emitting element on the first surface;
A bonding wire having an end ball and a wire portion extending from the end ball, a first portion formed on the second surface by the end ball, the first surface intersecting from the first portion, and Attaching to include a second portion extending over the end of the second surface and onto the connection of the first surface;
A method of manufacturing a light emitting element unit, comprising:

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