JPH07123202A - Picture device - Google Patents

Abstract

PURPOSE:To attain exact flip chip connection of a light receiving element array to a board, to use an inexpensive board, and to avoid improper contact due to difference from the bonding condition between the light receiving element array and a drive IC. CONSTITUTION:Common electrodes of LED arrays L1-L40 are connected to a 1st major side 34 of a common electrode board 30 and discrete electrodes of the arrays are in flip-chip connection to a 1st major side 4 of a discrete electrode board 2. The LED arrays are fixed to the board 30 and then in flip- chip connection to the board 2, and local heating by using hot air heater is applied to the connection. The boards 2,30 are set by a pin 56 to place spacers 52, 54 inbetween so as to avoid the board 2 from being tilted. The light from the LED arrays is led out through a throughhole provided to the board 2 and a reflection preventing section is provided to its inside. Furthermore, drive ICs 18,42 are arranged to a 2nd major side of the boards 2, 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image device such as an LED head, an image sensor and an EL head, and more particularly to a flip chip connection type image device.

[0002]

2. Description of the Related Art Image pickup devices such as LED heads
Proposal of flip-chip connection of light emitting array to substrate
Have been published (for example, Kokai Sho 63-180,249
News). Flip-chip connection has the advantage of high speed and large number of connections
There is something that can be done. However flip chip connection
Has the following problems, and
No prior art was found. 1)  When connecting, the bumps of the light emitting and receiving array and the pattern of the light receiving and emitting
You can't see the turns, you should look at the back of the array and mount it.
It Therefore, the mounting accuracy of the array is reduced. For example
± 100 at maximum between the outer shape of b and the actual electrode arrangement
There is an error of μm. 2)  The array is temporarily fixed when the flip chip connection is used.
In the state before swinging, use surface tension such as flux to
Surface tension of the bump material such as solder during bonding.
U However, the surface tension of the flux is small for accurate temporary fixing.
If the surface tension of solder or the like is too high, the flux will try to aggregate.
It cannot be used for accurate temporary fixing because it is hindered by surface tension.
Yes. 3)  For these reasons, the light emitting / receiving array must have a required accuracy of ± 10μ.
It is difficult to mount with an accuracy of m or less, about ± 50 μm
It becomes the mounting accuracy of. As a result, the
Using flip-chip bonding becomes difficult
It Four)  Flip-chip connection while pressing the array
However, the pressure may not be evenly applied and the array may be destroyed.
is there. Five)  The inventor mentioned above 1) ~Four) To avoid the problem of
Two electrodes are used and the common electrode of the light emitting / receiving array is fixed on the common electrode substrate.
In the fixed state, the individual electrode wiring on the individual electrode substrate receives and emits light.
We considered flip-chip connection of Ray (Patent application
5-180, 613). If you do this, flip
The pattern of the light emitting and receiving array can be seen when the chip is connected, and the array
Is fixed to the common electrode substrate, so flip chip
The array does not shift from the individual electrodes during subsequent
Since it is sandwiched with one board, all bumps are uniform
It can be pressurized. However, along with this, two bases
There was a problem that the plates tilted and did not become parallel. I.e.
If there is an elongated light emitting and receiving array between the plates, the
The line cannot be kept in line and the substrate is relatively tilted. 6)  When two substrates are used, individual electrode wiring is received and emitted by the light emitting array
Need to be positioned with respect to, and cannot be positioned
In this case, for example, if there is a defect such as connecting one bump at a time
Occurs.

The inventor has examined a substrate of an image device as another problem other than the above. A commonly used substrate is a glass substrate provided with thin film wiring, but the glass substrate is expensive, and it takes time to form the thin film wiring, which is not suitable for mass production. In addition, the thin film wiring has low adhesion to the substrate. Therefore, it is necessary to use a cheaper board such as a hard printed board. Next, the image device requires high-density wiring, but it is difficult to perform double-sided wiring using a through hole or the like on a glass substrate. Therefore, we examined using an opaque rigid printed circuit board, etc., to flip-chip connect the light emitting and receiving array, and use a through hole in the board to allow light to pass through. Then, the reflection of light on the inner surface of the through hole becomes a problem. That is, the width of the through hole is about 100 μm, which is slightly larger than the width of the light receiving and emitting body, and the substrate is thicker than this, so that reflection on the inner surface of the through hole becomes a problem.

In addition to this, the flip chip connection has the following problems. The drive ICs of the light emitting / receiving array, for example, the drive ICs of the common electrode and the drive ICs of the individual electrodes are generally different in height from the light receiving / emitting array. Therefore, the light emitting / receiving array and the drive I
It is difficult to flip-chip connect C and C at the same time. Further, the bump size is different between the drive IC and the light emitting / receiving array, and in general, the drive IC has a higher density of bumps and a smaller size. Simultaneous flip-chip connection of bumps with different connection conditions such as size and pitch leads to increased connection failure. Further, when the bumps of the driving IC are flip-chip connected at the same time as the bumps of the light receiving and emitting array, the number of connection points increases and the connection failure further increases.

[0005]

Problem to be Solved The invention of claim 1 is flip-chip connection.
The following problems are to be solved in a mold type image device. 1)  Flip chip while watching the pattern of the light emitting and receiving array
It enables connection and enhances mounting accuracy of the array. 2)  High accuracy of temporary fixing of array when flip chip connection
Therefore, the mounting accuracy of the array is improved. 3)  All the light emitting and receiving arrays are leveled when flip chip connection is performed.
Allows a single pressurization to prevent damage to the array. Four)  Enables the use of inexpensive hard printed circuit boards, and
Apply double-sided wiring to the board to reduce wiring density. Five)  Prevent the two boards from tilting and keep the two boards parallel.
keep.

The subject of the invention of claim 2 is the above 1). ~Five) In addition to
Yes, 6)  Accurate positioning of individual electrode wiring with respect to the light emitting / receiving array
To do. The subject of the invention of claim 3 is the above 1). ~Five)
In addition to 7)  Reflection of light through the through holes on the individual wiring board
To improve the image quality. Claim
The problem of the invention of No. 4 is 1) above. ~Five) In addition to 8)  Common electrode
The height of the driving IC or individual electrode driving IC is higher than that of the light emitting / receiving array.
The bump size and bump pitch are both high and low.
Even if it is different from B, it does not hinder the flip chip connection.
To do so. The subject of the invention of claim 5 is the above
1) ~Five) In addition to 9)  Allows formation of through holes on individual electrode substrates
It is easy and the individual electrode board is not tilted.
It is in. The subject of the invention of claim 6 is the above 1). ~Five) In addition to
10)  Flip-chip connection made easier, especially
After checking whether the connection is correct, finally connect
To be able to do so. Invention of Claim 7
The above is 1) above. ~Five) In addition to 11)  Common electrode drive I
Flip the C and individual electrode drive IC at the same time as the light emitting and receiving array.
Chip chip connection, and these are also used as spacers
To be able to do it. Problem of Invention of Claim 8
Is 1) above ~Five) In addition to 12)  Accurately arrange the bumps
Facilitates flip-chip connection, and
It is to facilitate the connection even when the flatness is low.

[0007]

According to the image device of the present invention, a common electrode substrate having a common electrode wiring on a first main surface, an individual electrode wiring on a first main surface, and a rear surface wiring on a second main surface are provided. , And an individual electrode substrate that connects both of these wires with through holes,
A common electrode on the bottom surface of the light emitting / receiving array is coupled to the common electrode wiring, and electrodes connected to individual light receiving / emitting bodies on the array surface are flip-chip connected to the individual electrode wiring to form the light receiving / emitting array as a common electrode substrate. It is sandwiched with an individual electrode substrate. Further, the individual electrode substrate is provided with a through hole at a position corresponding to the light receiving and emitting body of the array, and the height between the individual electrode substrate and the common electrode substrate is almost equal to that of the light receiving and emitting array. A spacer is provided.

The image device of the present invention is characterized in that the common electrode substrate and the individual electrode substrate are positioned by pins (claim 2). The image device of the present invention further includes
An antireflection portion is provided on the inner surface of the through hole to prevent light from being reflected by the through hole (claim 3). The image device of the present invention is also characterized in that a common electrode drive IC is provided on the second main surface of the common electrode substrate, and an individual electrode drive IC is provided on the second main surface of the individual electrode drive substrate. (Claim 4).

The image device of the present invention is characterized in that the individual electrode substrate is composed of two substrates cut along a line extending from the through hole (claim 5). The image device according to the present invention is characterized in that a resin is filled between the individual electrode substrate and the common electrode substrate, and the flip-chip connection is performed by a contracting force of the resin (claim 6). In the image device according to the present invention, the common electrode drive IC and the individual electrode drive IC have substantially the same thickness as the light receiving and emitting array.
Further, the common electrode drive IC is flip-chip connected to the common electrode wiring and the individual electrode drive IC is connected to the individual electrode wiring by flip-chip connection (claim 7). The image device of the present invention is characterized in that the bumps used for the flip-chip connection are constituted by stud bumps provided on the surface of the light receiving and emitting array.

The light emitting / receiving array is, for example, an LED array, E
An L array, plasma array, CCD array or the like is used. The substrate is preferably a hard printed circuit board, a flexible printed circuit board or the like, which is inexpensive and easy to process through holes.

[0011]

According to the first aspect of the invention, the light emitting / receiving array is sandwiched between the common electrode substrate and the individual electrode substrate and flip-chip connected to the individual electrode wiring provided on the first main surface of the individual electrode substrate. Further, through holes are provided in the individual electrode substrate so that light can go in and out. In this way, after connecting the common electrode on the bottom surface of the light emitting and receiving array to the common electrode wiring,
The individual electrode substrate can be set and flip-chip connected. Therefore, the individual electrode wiring can be set while looking at the electrodes on the array surface, and the mounting accuracy of the array is improved. Next, since the bottom surface of the light receiving and emitting array is bonded to the common electrode and flip chip connection is performed, the light receiving and emitting array does not move even if the force of temporarily fixing the bump material such as flux or solder is weak. Since the temporary fixing force by the flux and the bump material is weak, the individual electrode substrate may move with respect to the light emitting / receiving array, but in the case of the image device, the number of light emitting / receiving arrays is large and the number of bumps is extremely large. . Therefore, even if the temporary fixing force of the individual bumps is weak, the individual electrode substrate can be temporarily fixed with a large number of bumps and fixed to the light emitting / receiving array for flip-lip connection. The individual electrode substrate can be set while looking at the array electrodes, and the flip-chip connection can be performed after the array is connected to the common electrode wiring, so the accuracy of flip-chip connection is greatly improved, and the mounting error can be easily reduced to ± 10 μm or less. You can Next, flip-chip connection is performed by sandwiching the light emitting / receiving array between two substrates. Therefore, all the bumps used for flip-chip connection can be uniformly pressed, the reliability of the connection can be increased, and damage to the array can be prevented.

According to the first aspect of the present invention, the common electrode substrate or the individual electrode substrate is a substrate such as a hard printed circuit board or a flexible printed circuit board, which is easy to process through holes. For example, both of the substrates are hard printed circuit boards, or One is a rigid printed circuit board and the other is a flexible printed circuit board. A back surface wiring is provided on the second main surface (the main surface opposite to the light emitting / receiving array) of the individual electrode substrate, and is connected to the individual electrode wiring on the first main surface (the main surface on the light emitting / receiving array side) by a through hole. . The wiring density is high in the individual electrode substrate, but since double-sided wiring is applied and the spaces between them are connected by through holes, the wiring density of the substrate decreases, and inexpensive printed wiring should be used instead of expensive thin film wiring. Will be able to. Further, a spacer having a height substantially equal to that of the light emitting / receiving array is provided between the two substrates to prevent the substrates from tilting and keep the two substrates parallel to each other.

According to the second aspect of the present invention, the two substrates are positioned by the pins, and the individual electrode substrate is accurately positioned with respect to the light emitting / receiving array. Further, in the invention of claim 3, the antireflection portion is provided in the through hole provided in the individual electrode substrate. As a result, even when a thick hard printed board is used, it is possible to prevent reflection of light on the inner surface of the through hole and improve the image quality. Further, in the invention of claim 4, the driving IC is provided on the second main surface of the substrate.
Since the common electrode driving IC and the individual electrode driving IC are arranged, it is not necessary to simultaneously flip-chip connect the driving IC and the light emitting / receiving array having different chip heights, bump pitches, bump sizes, or the like. Further drive IC
Is arranged on the second main surface side of the common electrode substrate or the individual electrode substrate, the number of connection bumps at the time of flip chip connection of the light emitting and receiving array is reduced, and the connection is facilitated. As a result, the flip chip connection is facilitated and the connection reliability is significantly improved.

According to the invention of claim 5, the individual electrode substrate is divided into two to facilitate the formation of the through holes. The assembled individual electrode substrate is supported by the light emitting / receiving array, spacers, etc. and does not tilt. In the invention of claim 6, resin is filled between the individual electrode substrate and the common electrode substrate. The flip chip connection can be temporarily fixed by the force of the resin, and the light emitting and receiving array can be operated and tested before final bonding. Further, the contraction force of the resin keeps the contact of the connecting portion, and the resin is used to fix the individual electrode substrate and the double-sided wiring substrate to prevent the flip chip connecting portion from being overloaded. According to the invention of claim 7, the common electrode driving IC and the individual electrode driving IC are flip-chip connected at the same time as the light receiving and emitting array, and these spacers are also used. In the eighth aspect of the invention, the stud bumps provided in the light emitting / receiving array are used as the bumps for flip chip connection. Since the bumps can be formed after the light emitting / receiving array is arranged on the common electrode substrate, the bumps can be arranged accurately. Since a high tall bump can be formed, the lack of flatness of the individual electrode wiring can be compensated by the deformation of the bump, and even an individual electrode substrate having a low flatness can be connected without lowering the flatness of the array surface.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments are shown in FIGS. 1 to 6, FIG. 1 shows an individual electrode substrate, FIG. 2 shows a common electrode substrate, FIG. 3 shows an assembled image device, and FIGS. FIG. 6 shows flip chip connection by hot air heating. Although an LED head is used as an example in the embodiment, another image device such as an image sensor or an EL head can be obtained by replacing the light emitting / receiving array with another object. The drawing shows the main part of the image device, and omits well-known parts such as a lens array and a housing.

In FIG. 1, 2 is a rigid printed circuit board,
It may be a flexible printed circuit board or the like, and 4 is its first main surface and 6 is its second main surface. 8 is a through hole, LED
It is provided at a position corresponding to the light emitters of the arrays L1 to L40, and its width is about 100 μm. 10 is an individual electrode wiring,
Reference numeral 12 denotes a bump row provided on the side of the through hole 8 of the individual electrode wiring 10. The number of LED arrays L1 to L40 is 40, LE
If the number of light emitters per D array is 64, the total number of bumps to be connected is 2560. On the other hand, the individual electrode wiring 10 is provided in each of 20 sets above and below the through hole 8,
A total of 40 sets will be provided. The number of bumps per individual electrode wiring 10 is 64, and one individual electrode wiring 10
Since two sets of bump rows 12 and 12 are provided in the above, the number of bumps per bump row 12 is 32. The individual electrode wiring 10 is provided in units of two of the LED arrays L1 to L40, is folded back at the center, and 32 electrodes are flip-chip connected to the bump rows 12 and 12, respectively. There are 64 electrodes in one LED array, 32 of which are flip-chip connected to the lower bump row in the figure, and the remaining 32 are flip-chip connected to the upper bump row 12. As a result,
Each individual electrode wiring 10 may be 32 signal lines.

In the LED arrays L1 to L40, an electrode is led out to one side of the array for each light emitter, and the electrodes are arranged in line symmetry with respect to the center line XX of the array. This is determined by the individual electrode wiring 10. For example, if the electrode connected to the first light emitting body of the LED array L1 is connected to the lower individual wiring 10, up to the 31st light emitting body,
The electrodes of the odd-numbered light emitters are connected to the lower individual wiring 10, and in the 34th to 64th light emitters, the even-numbered light emitters are connected to the lower individual wiring 10. Next, the electrodes connected to the 2nd to 30th even light emitters are connected to the upper individual wiring 10, and the electrodes of the 32nd and 33rd light emitters are also connected to the upper individual wiring 10. The odd-numbered light emitters up to the th are connected to the upper individual wiring 10.
This is because the order of connection between the individual wiring 10 and the light emitters of the LED arrays L1 to L40 is reversed for each LED array, and therefore the first light emitter and the 64th light emitter are always the same in the individual wire 10. This is because it is necessary to connect to the signal line. Similarly, the second light emitting body and the 63rd light emitting body also need to be always connected to the same signal line. Therefore, as described above, if the electrodes are arranged in line symmetry with the boundary between the 32nd light emitting body and the 33rd light emitting body (X-X line) of the LED arrays L1 to L40 as a boundary, then each LED array Even if the direction of the individual wiring 10 is reversed, LE is always in the correct position.
The electrodes on the D array L1 to L40 side can be connected.

For the material of the bump row 12, for example, solder containing flux is used, and on the electrode side of the LED arrays L1 to L40, the flip chip connection portion is plated with gold or the like. However, it does not matter which side the bump is provided on.
Bumps may be provided on the ED arrays L1 to L40 side.

Reference numeral 14 is a backside wiring provided on the second main surface 6,
32 signal lines are arranged above and below the through hole 8, and 16 is a row of through holes for connecting the rear surface wiring 14 and the individual electrode wiring 10. Since a large area is required for the through holes, if they are arranged in one row, they will protrude from the individual electrode wiring 10. So through hole row 16
Are arranged in two rows and are arranged obliquely with respect to the longitudinal direction of the substrate 2, and the through hole row 1 is provided in a narrow range of the individual electrode wiring 10.
6 can be provided.

Reference numeral 18 denotes an individual electrode driving IC for driving the individual electrodes of the LED arrays L1 to L40. The chip height is different from that of the LED arrays L1 to L40 and the number of terminals is large, so that the number of bumps is large. And its size is small,
The array pitch is also small. Therefore, the individual electrode drive IC 18 is arranged on the main surface 6 on the side opposite to the LED arrays L1 to L40 to avoid the difficulty of connection due to the difference in flip chip conditions. 20 is an external connection terminal. Individual electrode drive IC
18 needs to be connected to the external connection terminal 20 and the back wiring 14. This connection may be flip chip connection,
In order to prevent the individual electrode driving IC 18 from being contaminated by the flux used for the flip chip connection, especially if there is a pinhole in the protective film that masks a portion other than the bump of the driving IC 18, the flux will penetrate from there and the driving IC 18 will be exposed. A wire bond connection is preferably used to prevent the wiring from being damaged. Reference numeral 22 denotes a pin hole, which is provided by using a mark formed at the same time as the individual electrode wiring 10. Therefore, the pin hole 22 is ± with respect to the individual electrode wiring 10.
It can be formed with an accuracy of about 5 μm.

FIG. 2 shows the common electrode substrate 30. For example, a hard printed circuit board is used for the common electrode substrate 30, 32 is a first main surface thereof, and 34 is a second main surface thereof. 36 is a common electrode wiring, 38 is a through hole for connecting to the second main surface 34 side, 40 is a conductive adhesive such as silver paste connected to the common electrode wiring 36, and LED arrays L1 to L
The common electrode on the bottom of 40 is bonded. A common electrode drive IC 42 for time-divisionally driving the LED arrays L1 to L40 one by one is provided on the second main surface 34 of the common electrode substrate 30, and connected to the common electrode wiring 36 via a wire bonding pad 44. . Reference numeral 46 denotes a backside bus for connecting the external connection terminal 48 and the common electrode driving IC 42.

The common electrode drive IC 42 is wire-bonded to the backside bus 46 and the common electrode drive IC 42. The common electrode driving IC 42 is arranged on the second main surface 34 on the opposite side of the LED arrays L1 to L40, because it is difficult to perform flip chip connection because of differences in chip height, bump pitch, size and the like. This is to avoid The common electrode drive IC 42 arranged on the second main surface 34 has bumps 44
Although it may be flip-chip connected to the bus 46, wire bonding is used to prevent the flux used for the flip-chip connection from invading the wiring of the drive IC 42. Reference numeral 50 is a pin hole, which is created based on the mark formed at the same time as the common electrode wiring 36, and is ± 5 with respect to the common electrode wiring 36.
It has an accuracy of about μm.

FIG. 3 shows a state after flip chip connection. The LED arrays L1 to L40 are sandwiched between two substrates 2 and 30 and light is extracted from the through hole 8 shown in FIG. Before flip chip connection, individual electrode drive IC18
Is wire-bonded to the back wiring 14 and the external connection terminal 20, and the common electrode drive IC 42 is wire-bonded to the wire bonding pad 44 and the back bus 46. LE
In the D arrays L1 to L40, positioning markers (not shown) are provided on the light emitter side, and the first principal surface 32 of the common electrode substrate 30 is provided.
It is mounted while collating with a marker (not shown) provided in the above, and is bonded with a conductive adhesive 40. Here, the LED arrays L1 to L
Since it can be mounted while looking at the 40 light emitter side, each light emitter can be mounted with an error of ± 10 μm or less.

52 and 54 are spacers, which are the individual electrode substrates 2
It is intended to prevent the device from being tilted. Spacers 54 are provided at one to several places in the central portions of the substrates 2 and 30.
, Spacers 52 are provided at both ends, and a spacer 54 at the center is provided.
Are provided on both sides of the row of the LED arrays L1 to L40. Further, reference numerals 56 and 56 are positioning pins, which are positioned in the pin holes 22 and 50 to position the substrates 2 and 30. The pin hole 22 is arranged with an accuracy of about ± 5 μm with respect to the individual electrode wiring 10, and the pin hole 50 is ± 5 with respect to the common electrode wiring 36.
Since they are arranged with an accuracy of about μm, the pin holes 22, 5
Pass the pin 56 through 0 to move the two boards 2 and 30 to ± 10μ.
Positioning can be performed with an error of m or less. For this reason,
Defects such as shifting each electrode of the LED arrays L1 to L40 by one bump and performing flip-chip connection are eliminated. Then, the substrates 2 and 30 are positioned in this way, and the electrode patterns of the LED arrays L1 to L40 are confirmed before the substrate 2 is set, and the individual electrode substrate 2 is set so that the bump rows 12 are aligned with this. . Also spacer 5
Flip-chip connection is performed in a state in which the substrate 2 is prevented from tilting at 2, 54. By doing so, even if the force of temporary fixing by flux, solder or the like at the time of flip chip connection is weak, each light emitting body of the LED arrays L1 to L40 is within ± 10 μm with respect to the bump row 12 of the individual electrode wiring 10. Flip chip connection is possible due to mounting error. Since the substrates 2 and 30 are fixed by the pins 56, the LED arrays L1 to L40 can be used even if the temporary fixing force of flux or the like is weak.
There is no risk that each electrode of will shift from the bump. Pin 5
6,56 may be removed after flip-chip connection.

FIG. 4 shows a cross section taken along the line AA of FIG. In the figure, reference numeral 60 denotes an antireflection portion provided on the inner wall of the through hole 8. The individual electrode substrate 2 has a thickness of about 1 mm, while the through hole 8 has a width of only about 100 μm. This is to prevent the light from the light-emitting body from being reflected on the inner wall of the sheet and degrading the image quality. The antireflection portion 60 is composed of, for example, a pigment or the like applied in a matte state, and
It is preferable that the reflectance per time is 20% or less. 6
2 and 64 are mold resins such as epoxy and silicon resin, which are used to protect the drive ICs 18 and 42. 6
6, 68 are backside wiring 14 and wire bonding pads 4
4 is a wire line.

As is apparent from FIG. 4, the spacers 52,
Without 54, the individual electrode substrate 2 would have the LED arrays L1-L
The LED arrays L1 to L40 may be attached obliquely to the LED array 40, and the LED arrays L1 to L40 may be damaged or the flip chip connection may be defective. Therefore, the spacers 52, 54
The LED arrays L1 to L40 have a thickness substantially the same as that of the LED arrays L1 to L40. The thickness of the bumps 12 and the conductive adhesive 40 are taken into consideration so that the individual electrode substrate 2 is set horizontally. Establish. The spacers 52 and 54 are, for example, LE
The D array itself may be used. In addition, the spacer 52,
The reference numeral 54 indicates that the boards 2 and 30 are combined even after the LED head is assembled, and the boards are tilted by an external force, or the LED arrays L1 to L40.
To prevent excessive force from being applied to.

FIG. 5 shows a cross section taken along line BB of FIG. 5
Reference numeral 2 denotes spacers arranged at both ends of the substrates 2 and 30, and the width thereof is made larger than that of the LED arrays L1 to L40 so that the individual electrode substrate 2 is not inclined at both ends. Reference numeral 56 is the pin for positioning the substrates 2 and 30 at both ends so that each electrode of the LED arrays L1 to L40 appears at the correct bump position of the bump row 12.

FIG. 6 shows flip-chip connection using a hot air heater. A reflow furnace may be used for flip chip connection, but the melting point of the solder bump 12 is about 150 ° C.
The heat resistant temperature of the substrates 2 and 30 is about 100 ° C. Therefore, if a reflow furnace is used, the substrates 2 and 30 may be deformed, and a hot air heater that is easy to locally heat is used.

In the figure, reference numeral 70 denotes a hot air nozzle of a hot air heater, from which hot air is blown as indicated by an outlined arrow in the figure. A guide plate 72 guides hot air into the through holes 8 through the long slit-like through holes 74, and locally heats the flip chip connection portion from there. In the flip-chip connection using a hot air heater, the flip-chip connection can be performed in a heating time of about 1 to 3 seconds, and overheating of the substrates 2 and 30 is small. Further, if the guide plate 72 is used and the hot air is intensively introduced from the through holes 74, the hot air does not come into contact with other portions, and the risk of deforming the individual electrode substrate 2 is further reduced. Even in this case, the second main surface 6 of the individual electrode substrate 2 is slightly heated, but the back wiring 14 and the through hole 16 play a role of releasing heat. That is, the back surface wiring 14 is provided on the second main surface 6, and the heat transferred from the guide plate 72 to the back surface wiring 14 escapes to the first main surface 4 side through the through holes 16. Therefore, the risk that the second main surface 6 of the individual electrode substrate 2 is overheated is further reduced.

[0030]

Example 2 Examples 2 to 4 show various improvements of the first example. Except for the points particularly pointed out, it is the same as the first embodiment. 7 and 8 show an embodiment in which the individual electrode substrate 2 is composed of two substrates 2-1 and 2-2. The width of the through hole 8 for extracting the LED light is about 100 μm, and the length thereof is about 20 cm. Since it is difficult to process a narrow and long through hole, the substrate 2 is composed of two substrates 2-1 and 2-2 divided by a line extending the through hole 8, and the through hole 8 is the substrate 2-1. , 2-2 by cutting the edge. For example, a router is used for edge grinding. Further, in this embodiment, the individual electrode driving ICs 18 and 18 are arranged on the same main surface as the individual electrode wirings 10, and accordingly, the individual electrode wirings 10-1 connected to the ICs 18 and 18 are provided, and from the IC 18 to the individual electrode wirings 10-1. , The rear surface wiring 14, and the individual electrode wirings 10 are connected in this order.

The substrates 2-1 and 2-2 are adhered and adhered to each other on both outer sides of the through hole 8 to form the ICs 18 and 18 and the LED array L1.
~ L40 flip chip connection, spacer 52,
Supported by 54. Therefore, the substrates 2-1 and 2-2 do not tilt.

[0032]

[Third Embodiment] FIGS. 9 to 11 show individual electrode driving ICs 18,
18 to the spacers 52 at both ends, and a common electrode drive IC
An example in which 42 is also used as the spacer 54 in the central portion is shown. In this embodiment, the thermosetting resin 80 is used for flip chip connection.
The contraction force of is used. There are two substrates 2 for the individual electrode substrate.
-1, 2-2 were used.

The ICs 18 and 42 are connected to the LED arrays L1 to L
Wafer with almost the same thickness as 40 (for example, 400 μm thick)
Manufactured in the same height as the LED arrays L1 to L40,
The electrode pitch is made substantially equal to that of the LED arrays L1 to L40. An insulating film 82 is provided to prevent a short circuit via the bottom surface of the IC 18, 42. Since the common electrode drive IC 42 is arranged on the same main surface 32 as the LED arrays L1 to L40,
The common electrode wiring is changed to the common electrode wiring 84 in FIG. Also, on both outer sides of the row of LED arrays L1 to L40,
The thermosetting resin 80 is filled.

In this way, the spacers 52 and 54 are
There is no need to make it separately, and IC18 and 42 are substrates
Since it is housed between 2 and 30, IC18 and 42 protection
Will be easier. For flip chip connection, reflow furnace or
The adhesive force of the resin 80 can be used for temporary fixing before heating with hot air.
Moreover, the LED arrays L1 to L40 operate at this stage.
It This is the adhesive strength of the resin, and the flip-chip joint
This is because the contact is obtained. Then 1)  For temporary fixing
2) There is no risk of the connection part shifting  Before the final connection
Each LED can be operated to perform an electrical test of the imaging device. This
Connection failure, LED array L1 to L40 failure,
Check for abnormalities in lines 10 and 36, and defects in ICs 18 and 42.
You can After these checks, for example, as shown in Figure 11.
Then, the flip chip connection is completed by hot air heating or the like.
The hot air is heated by blowing hot air through the through holes 74 provided in the guide plate 72.
Implant, apply only the flip chip connection and resin 80 locally
It is preferable to heat.

When the resin 80 is hardened, the contraction force of the resin 80 attracts the substrates 2 and 30, and this force maintains the contact at the flip chip connection portion. Therefore, it is not necessary to use solder bumps for flip chip connection, and for example, a combination of gold bumps and gold-plated wiring or copper wiring may be used. In the case of using the solder bump, the contact due to the contraction force of the resin 80 is added to the contact due to the melting of the solder, so that a more reliable contact can be obtained as compared with the case of simple solder connection. The cured resin 80 fixes the substrates 2 and 30 and prevents a bending moment or the like from being applied to the flip chip connection portion to break the connection.

[0036]

Fourth Embodiment A stud bump 86 is shown in FIGS.
The example used is shown below. The stud bump 86 is a common electrode substrate.
The electrode pads of the LED arrays L1 to L40 arranged in 30
Then, ball-bond a gold wire, etc., and cut the top of the ball.
I refused. The characteristics of the stud bump 86 are 1)  
Easily obtain tall bumps, for example 50 μm or more in height
And 2)  Formed after arraying arrays L1 to L40
Since it is possible, it is possible to arrange all the bumps 86 on a straight line.
And in. The fact that the bumps 86 are tall means that the individual electrode substrate
2 even if the flatness of the first main surface 4 is insufficient,
The height of the light emitting bodies of the LED arrays L1 to L40, which is compensated for by the deformation
Means that they can be aligned.

After arraying the LED arrays L1 to L40,
The fact that the dead bump 86 can be formed is, for example, as shown in FIG.
LED array L2 is out of position, or the array
The position of the pad for bump formation is misaligned due to
Even when the stud bumps 86 are aligned, the positions of the stud bumps 86 are aligned on a straight line.
Means that. Therefore, all the bumps 86 of FIG.
Straight line l1 , L2 Flip chip connection
The alignment becomes extremely easy. In addition, the stud bump 86
Is formed after the arrays L1 to L40 are arranged.
1) compared to the case where bumps are formed at the wafer stage  Wafer
Is not damaged by the impact of bump formation, and the yield is
Improved, 2)  Because of the formed bumps,
It has the feature that it is not difficult to handle.

[0038]

According to the invention of claim 1, the following effects can be obtained.
Be done. 1)  Flip chip while watching the pattern of the light emitting and receiving array
It enables connection and enhances mounting accuracy of the array. 2)  High accuracy of temporary fixing of array when flip chip connection
Therefore, the mounting accuracy of the array is improved. 3)  All the light emitting and receiving arrays are leveled when flip chip connection is performed.
Allows a single pressurization to prevent damage to the array. Four)  Enables the use of inexpensive hard printed circuit boards, and
Apply double-sided wiring to the board to reduce wiring density. Five)  Prevent the two boards from tilting and keep the two boards parallel.
keep.

According to the invention of claim 2, further 6)  Individual electrode
The wiring can be accurately positioned with respect to the light emitting / receiving array. Also
In the invention of claim 3, further 7)  Provided on an individual wiring board
Preventing the reflection of light at the through holes and improving the image quality.
You can In the invention of claim 4, further 8)  Common electrode drive
The height of the dynamic IC and the individual electrode drive IC is higher than that of the light emitting / receiving array.
High light emitting / receiving array with bump size and bump pitch
Does not interfere with flip-chip connection
You can

According to the invention of claim 5, 9)  Individual electrode
It facilitates the formation of through holes in the substrate,
You can prevent it from leaning. In this case, 2 minutes
The divided individual electrode substrate is supported by a light emitting and receiving array, spacers, etc.
It does not get tilted. And since the board was divided into two,
It becomes easy to process the elongated through holes. Invention of Claim 6
Then, 10)  Flip-chip connection made easier
Then, test the light-emitter and receiver to see if the connection is correct.
After confirming that, you can finally connect. This
In the case of, the connection part is temporarily fixed by the force of the resin, and before the final connection
The light emitting and receiving array can be operated and tested. That
After the inspection, the resin can be cured and the final connection can be made.
It Also, if the contact of the connection part is maintained by the shrinkage force of the resin,
Then, fix the individual electrode board and the double-sided wiring board with resin, and
It is possible to prevent excessive force from being applied to the lip tip connection part. Contract
In the invention of claim 7, further 11)  Common electrode drive IC and individual
Separate electrode drive IC and flip chip at the same time as the light emitting and receiving array
These can be connected and the spacer can also be used as these.
In the invention of claim 8, further 12)  Accurately arrange bumps
To facilitate flip chip connection and individual electrode substrate
The purpose is to facilitate the connection even when the flatness is low.
In this case, the stud bumps will be
And bumps can be accurately arranged on the common electrode substrate.
It Also, the stud bumps are tall with a high aspect ratio.
Since bumps can be easily formed, flatness of individual electrode wiring
Of bumps is compensated by bump deformation, and individual electrode substrate with low flatness
Even a plate can be connected without degrading the flatness of the array surface.
You can

[Brief description of drawings]

FIG. 1 is a diagram showing the front and back states of individual wiring boards of an image device according to an embodiment.

FIG. 2 is a diagram showing a state of front and back surfaces of a common electrode substrate of the image device of the embodiment.

FIG. 3 is a side view of a main part of the image device according to the embodiment.

4 is an enlarged cross-sectional view taken along the line AA of FIG.

5 is an enlarged cross-sectional view taken along line BB of FIG.

FIG. 6 is a cross-sectional view showing a flip-chip connection process in an example.

FIG. 7 is a plan view of an individual wiring board according to a second embodiment.

FIG. 8 is a sectional view of an essential part of the second embodiment.

FIG. 9 is a cross-sectional view of the essential parts of the third embodiment.

FIG. 10 is a plan view of a common electrode substrate according to a third embodiment.

FIG. 11 is a cross-sectional view showing a flip chip connection process in the third embodiment.

FIG. 12 is a plan view of an essential part of the fourth embodiment.

FIG. 13 is a side view of an LED array according to a fourth embodiment.

FIG. 14 is a plan view showing the arrangement of bumps in the fourth embodiment.

[Explanation of symbols]

 Two Individual electrode substrate 2-1, 2-2 Individual electrode substrate 4 First major surface 6 Second main surface 8 Through hole 10, 10-1 Individual electrode wiring 12 Bump row 14 Backside wiring 16 Through hole row 18 Individual electrode drive IC 20 External connection terminal 22 Pin hole 30 Common electrode substrate 32 First main surface 34 Second main surface 36 Common electrode wiring 38 Through hole 40 Conductive adhesive 42 Common electrode drive IC 44 Wire bonding pad 46 Back bus 48 External connection terminal 50 Pin hole 52, 54 Spacer 56 Pin 60 Antireflection part 62,64 Mold resin 66,68 Wire wire 70 Hot air nozzle 72 Guide plate 74 Through hole 80 Thermosetting resin 82 Insulation film 84 Common electrode wiring 86 Stud bump

Claims (8)

[Claims] 1. A common electrode substrate having a common electrode wiring on a first main surface, an individual electrode wiring on a first main surface, a back surface wiring on a second main surface, and both wirings. An individual electrode substrate connected by a through hole is provided, the common electrode on the bottom surface of the light receiving and emitting array is connected to the common electrode wiring, and the electrode connected to the individual light receiving and emitting body on the array surface is flip-chip connected to the individual electrode wiring. Then, the light emitting / receiving array is sandwiched between a common electrode substrate and an individual electrode substrate, and the individual electrode substrate is provided with a through hole at a position corresponding to the light emitting / receiving body of the array. An image device in which a spacer having a height substantially equal to that of the light emitting and receiving array is arranged between the substrate and the substrate. 2. The common electrode substrate and the individual electrode substrate,
The imaging device according to claim 1, wherein the imaging device is positioned by a pin. 3. The image device according to claim 1, wherein an antireflection portion is provided on the inner surface of the through hole. 4. A common electrode driving IC is provided on the second main surface of the common electrode substrate, and an individual electrode driving IC is provided on the second main surface of the individual electrode driving substrate.
The image apparatus according to claim 1, further comprising: 5. The image device according to claim 1, wherein the individual electrode substrate is composed of two substrates cut along a line extending from the through hole. 6. The image device according to claim 1, wherein a resin is filled between the individual electrode substrate and the common electrode substrate, and the flip-chip connection is performed by a contracting force of the resin. 7. The common electrode driving IC and the individual electrode driving I
2. The image device according to claim 1, wherein C has a thickness substantially equal to that of the light emitting / receiving array, and the common electrode driving IC is flip-chip connected to the common electrode wiring and the individual electrode driving IC is connected to the individual electrode wiring, respectively. . 8. The image device according to claim 1, wherein the bump used for the flip-chip connection is constituted by a stud bump provided on the surface of the light receiving and emitting array.