JPH0555633A - Optical device and its manufacture - Google Patents

Abstract

PURPOSE:To prevent residual flux in a light transmission path from mixing into transparent resin of an optical device. CONSTITUTION:A solder bump 5 with flux 19 applied on an end of a light emitting element array chip 13 is formed, while an anti-tilting stud 6 without flux applied is provided at the opposite end, and transparent resin 20 for protecting the light emitting element array chip 13 and the solder bump 5 is injected from a side of the anti-tilting stud 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device in which a light emitting element array chip having a light emitting portion and a solder bump is surface-mounted on a semiconductor substrate, and a method of manufacturing the same.

[0002]

2. Description of the Related Art FIG. 7 is a sectional view of a conventional optical device, FIG. 8 is a plan view thereof, FIG. 9 is a front view of a light emitting element array, FIG. 10 is a sectional view of the same, and FIG. FIG. 12 is a sectional view showing a state before reflow, and FIG. 12 is a sectional view showing a state after the reflow and cleaning.

In FIGS. 9 and 10, 13 is a light emitting element array chip (LED array chip), 1 is a semiconductor substrate of gallium arsenide (GaAs) or the like, and a selective diffusion mask / insulating film 1a made of silicon nitride or the like is formed, A perforated portion for diffusion is provided in the central portion, and a pn junction is formed in the perforated portion by a diffusion method or the like to form the light emitting section 2. Reference numeral 4 denotes a power feeding electrode made of aluminum or the like, which are alternately arranged in a direction orthogonal to the arrangement direction of the light emitting portions 2, and an insulating coating 3 made of silicon nitride or the like is deposited thereon. The insulating coating 3 has a perforated portion, on which a barrier layer (not shown) and solder bumps 5 are sequentially formed by a plating method or the like.

Next, a 300 DPI optical device in which the light emitting element array chip 13 is mounted will be described by taking a print head as an example.

As shown in FIGS. 7 to 8, the substrate 8 is made of a translucent material such as glass, and a fiber bundle 9 composed of a large number of optical fibers is embedded in the substrate 8. The surface of the fiber bundle 9 is made of aluminum and copper by a thin film process. And the like, and a common electrode pattern 11 are formed, and an insulating coating 12 made of silicon nitride or the like is formed except for the connection portion.

On the conductor pattern 10, a light emitting element array chip 13 and an IC chip 15 for controlling the light emitting element array chip 13 are respectively connected by solder bumps 5 and serve as one terminal for emitting light. The light emitting portion 2 of the light emitting element array chip 13 faces the fiber bundle 9.

In the method of connecting the solder bumps 5, as shown in FIG. 11, a flux 18 is applied on the conductor pattern 10 by a transfer method using a bonder, and the light emitting element array chip 13 and the IC chip 15 are mounted thereon. The light emitting element array chip 13 and the IC chip 15 are
Then, the solder bumps 5 are melted by passing through the reflow process as shown in FIG.

Next, the flux 18 is washed with acetone, IPA or the like.

A transparent resin 20 made of a material such as epoxy resin is filled between the substrate 8 and the light emitting element array chip 13 and the IC chip 15 by a dispenser or the like, and the light emitting element array chip 13, the IC chip 15 and the solder. It protects the bumps 5 and also serves to transmit the light emitted from the light emitting portion 2 of the light emitting element array chip 13 and irradiate it onto the photoconductor through the fiber bundle 9.

The common signal electrode 14 on the back surface of the light emitting element array chip is connected to the common electrode pattern 11 by applying a conductive resin 21 such as an epoxy resin mixed with silver powder by a dispenser or mask printing. It works as a common electrode side terminal for emitting light.

In the case of 300 DPI, 40 light emitting element array chips 13 are arranged on a straight line, and a total of 2560 light emitting elements 2 of the light emitting element array chip 13 are arranged on a straight line.

[0012]

However, in the conventional method, the solder bumps 5 are provided on both sides in the steps of reflowing and cleaning after the light emitting element array chip 13 is bonded by face down (F / D) bonding, and therefore, as shown in FIG. However, the flow of the cleaning liquid is poor, and the flux residue 19 remains in the central light emitting unit 2, which impedes the transmission of light emitted from the light emitting unit 2.

Further, when the transparent resin 20 is injected, the flux residue 19 adhering to the periphery of the solder bumps 5 is mixed into the transparent resin 20, which also causes a problem of impeding light transmission.

In view of the above problems, it is an object of the present invention to provide an optical device capable of preventing a residue of a flux in a light transmission path in a transparent resin after injecting the transparent resin, and a manufacturing method thereof.

[0015]

The means for solving the problems according to claim 1 of the present invention is to irradiate the irradiation light from the light emitting element array chip 13 to the outside through the substrate 8 as shown in FIGS. The light emitting element array chip 13 is surface-mounted on the transparent substrate 8 with a gap X, and is connected between the electrode 4 of the light emitting element array chip 13 in the gap X and the conductor pattern 10 on the substrate 8. In the optical device in which the solder bump 5 for soldering is interposed and the gap X is sealed with the transparent resin 20, the electrode 4 is the light emitting element array chip 1
3 is arranged only at one end of the light emitting element array chip 1
The other end of 3 is provided with a protrusion 6 for preventing inclination.

According to a second aspect of the present invention, the electrode means 4 is formed at one end of the light emitting element array chip 13, the solder bumps 5 are projectingly formed on the electrode 4, and the other end of the light emitting element array chip 13 is prevented from tilting. Protrusions 6 are formed on the solder bumps 5, a flux 18 is applied to the solder bumps 5, and the solder bumps 5 are brought into contact with the conductor patterns 10 on the substrate 8 to temporarily connect the solder bumps 5 between the light emitting element array chip 13 and the substrate 8. On board 8
With the above, the solder reflow is performed and the surface mounting is performed, and the transparent resin 20 is injected from the protrusion 6 side of the void X to seal the void X with the resin.

[0017]

In the above means for solving the problems, the flux 18 is applied to the solder bumps 5, and the solder bumps 5 are brought into contact with the conductor patterns 10 on the substrate 8 to be temporarily connected. At this time, the protrusion 6
Do not apply flux to the. Next, the substrate 8 is held between the light emitting element array chip 13 and the substrate 8 by solder reflow and surface mounting. Then, the transparent resin 20 is injected from the protrusion 6 side of the void X to seal the void X with resin.

At this time, since the flux is not applied around the projection 6 serving as the injection port, it is possible to prevent the residue of the flux from being mixed when the transparent resin 20 is injected.

[0019]

1 is a sectional view showing an optical device of a first embodiment of the present invention, FIG. 2 is a plan view thereof, FIG. 3 is a front view of a light emitting element array chip, FIG. 4 is a sectional view thereof, and FIG.
Is a sectional view showing a state before the reflow of the optical device, and FIG. 6 is a sectional view showing a state after the reflow and cleaning similarly.

As shown in FIGS. 1 to 6, the optical device of this embodiment is
Used in LED printers, etc., light emitting element array chip 1
L for irradiating the irradiation light from No. 3 to the outside through the substrate 8
ED print head, light emitting element array chip 1
3 is surface-mounted on the transparent substrate 8 with a gap X, and solder bumps 5 for connection are provided between the electrode 4 of the light emitting element array chip 13 in the gap X and the conductor pattern 10 on the substrate 8.
And the gap X is sealed with the transparent resin 20.

First, the light emitting element array chip 13 will be described. In FIGS. 3 and 4, reference numeral 1 denotes a semiconductor substrate made of gallium arsenide (GaAs) or the like, on which a selective diffusion mask / insulating film 1a made of silicon nitride or the like is formed, and a perforation portion for diffusion is provided in the central portion, and the perforation portion is provided. P depending on the diffusion method
An n-junction is formed to form the light emitting section 2. Reference numeral 4 denotes a power feeding electrode made of aluminum or the like, which are alternately arranged in a direction orthogonal to the arrangement direction of the light emitting portions 2, and an insulating coating 3 made of silicon nitride or the like is deposited thereon. A perforated portion is formed at one end of the insulating coating 3, and a barrier layer and a solder bump 5 by a plating method or the like are sequentially formed thereon. The barrier layer is omitted.

On the other end of the light emitting element array chip 13, that is, on the opposite side of the solder bump 5, a pad 7 made of a material such as nickel or titanium is formed, and an insulating coating 3 is applied thereto. The insulating coating 3 is provided with a perforated portion, and 2 is formed on the perforated portion.
Ten to ten inclination preventing projections 6 (studs) made of a material such as copper are formed by a plating method or the like.

Next, referring to FIGS. 1 and 2, a 300 DPI print head on which the light emitting element array chip 13 is mounted will be described.

The substrate 8 is made of a translucent material such as glass, and a fiber bundle 9 made up of a large number of optical fibers is embedded in the substrate 8. The surface of the substrate bundle 9 is formed by a thin film process by a conductor pattern 10 such as aluminum and copper and a common electrode. Pattern 1
1 is formed, and the insulating coating 12 made of silicon nitride or the like is formed except the connection portion.

On the conductor pattern 10, a light emitting element array chip 13 and an IC chip 15 for controlling the light emitting element array chip 13 are connected by solder bumps 5, respectively, and serve as one terminal for emitting light. The light emitting portion 2 of the light emitting element array chip 13 faces the fiber bundle 9.

In the print head having the above structure, as shown in FIG.
As described above, the solder bump 5 is formed on one end of the light emitting element array chip 13, and at the same time, the tilt preventing projection 6 is provided on the other end.

Next, the flux 18 is applied to the conductor pattern 10 by a transfer method using a bonder, the solder bumps 5 are brought into contact with the flux 18, and the light emitting element array chip 13 and the IC chip 15 are mounted. Light emitting element array chip 13
The IC chip 15 and the IC chip 15 are temporarily adhered by the flux 18. At this time, the flux 18 is not applied to the insulating coating 12 which is the adhesion point of the protrusion 6. In this state, as shown in FIG. 6, the solder bumps 5
Melts and is connected to the conductor pattern 10. At the same time, the protrusions 6 melt and adhere to the insulating coating 12.

Next, after washing the flux 18 with acetone, IPA or the like, a transparent resin 20 made of a material such as an epoxy resin is placed in the space X between the substrate 8 and the light emitting element array chip 13 and the IC chip 15 with a dispenser. Etc. At this time, the transparent resin 20 is used as the light emitting element array chip 1.
It is injected from the inclination preventing projection 6 side of No. 3.

At this time, since the flax is not applied to the side of the protrusion 6, there is no residue 19 of the flax and the transparent resin 2
It is possible to prevent the flux from being mixed into 0.

A residue 19 of the flux may remain around the solder bump 5. However, since the transparent resin 20 is injected from the opposite side of the solder bump 5, the residue 19 of the flux is the light emitting element array chip. It does not flow to the position where the light irradiation of 13 is blocked.

Thereafter, the common signal electrode 14 on the back surface of the light emitting element array chip is connected to the common electrode pattern 11 by applying a conductive resin 21 such as an epoxy resin mixed with silver powder by a dispenser or mask printing. To do.

By the above operation, in the case of 300 DPI,
Forty light emitting element array chips 13 are arranged on a straight line, and a total of 2560 light emitting portions 2 of the light emitting element array chips 13 are arranged on a straight line.

Although the present embodiment has been described with respect to the case of the print head, the present invention is not limited to this, and it can be used for all optical devices such as a light emitting device display device having a light emitting device array chip or a light receiving chip.

[0034]

According to claims 1 and 2 of the present invention, a solder bump is formed at one end of the light emitting element array chip, and
Since the protrusions for preventing tilt are provided on the other end, when the surface of the light-emitting element array chip is not coated with flux, the flow of the cleaning liquid is improved in the subsequent reflow and cleaning processes, and the cleaning performance is improved. It is possible to prevent the residue of the flux remaining in the central light emitting portion from interfering with the transmission of light due to the solder bumps on both sides as in the conventional case.

Further, by injecting the transparent resin from the side of the inclination preventing protrusion where the flux is not applied, the residue of the flux adhered around the solder bumps is mixed into the transparent resin as in the conventional case, which hinders the transmission of light. It has an excellent effect when it can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view of an optical device according to an embodiment of the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a front view of a light emitting element array chip of the same.

FIG. 4 is a sectional view of the same.

FIG. 5 is a sectional view showing a state before reflow of the optical device, similarly.

FIG. 6 is a cross-sectional view showing a state after the reflow and the cleaning, similarly.

FIG. 7 is a sectional view of a conventional optical device.

FIG. 8 is a plan view of the same.

FIG. 9 is a front view of a light emitting element array chip of the same.

FIG. 10 is a sectional view of the same.

FIG. 11 is a sectional view showing a state before reflow of the optical device, similarly.

FIG. 12 is a cross-sectional view showing a state after the reflow and the cleaning, similarly.

[Explanation of symbols]

 4 Supply Electrode 5 Solder Bump 6 Tilt Prevention Protrusion 8 Substrate 10 Conductor Pattern 13 Light-Emitting Element Array Chip 16 Conductor Pattern 20 Transparent Resin X Void

Claims (2)

[Claims] 1. A device for irradiating light emitted from a light-emitting element array chip to the outside through a substrate, wherein the light-emitting element array chip is surface-mounted with a void on a translucent substrate. In the optical device in which a solder bump for connection is interposed between the electrode of the light emitting element array chip and the conductor pattern on the substrate, and the gap is sealed with a transparent resin, the electrode is formed of the light emitting element array chip. An optical device characterized in that it is arranged only at one end, and a protrusion for preventing inclination is provided at the other end of the light emitting element array chip. 2. An electrode is formed on one end of the light emitting element array chip, a solder bump is formed on the electrode, and a protrusion for preventing inclination is formed on the other end of the light emitting element array chip, and a flux is formed on the solder bump. Applying the solder bumps to the conductor pattern on the board for temporary connection, solder reflow with the board between the light emitting element array chip and the board for surface mounting, and transparent resin from the protruding side of the void. A method for manufacturing an optical device, which comprises injecting and sealing a void with a resin.