JPH05121710A - Light emitting / receiving element array module - Google Patents

Abstract

(57) [Summary] [Object] To provide a light emitting and receiving element array module with little leakage light. In a light emitting and receiving element array module in which a light emitting and receiving element array 11, a glass plate-shaped microlens array 13 and an optical fiber array 12 are sequentially stacked, an electrode 16 having a predetermined shape is formed on one surface of the microlens array 13.
Forming a pattern, the electrode 1 of the microlens array 13
6 and the electrode 16 of the light emitting and receiving element array 11 are flip-chip bonded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting / receiving element array module for parallel transmission.

[0002]

2. Description of the Related Art In the wiring inside a computer, induction,
In order to eliminate various obstacles such as crosstalk and achieve high density and long distance, studies on optical transmission are being advanced.
Optical transmission methods include an optical parallel transmission method and an optical serial transmission method. Of these, the optical parallel transmission method is
It is superior to the optical serial transmission system in that it enables large-capacity transmission by increasing the number of transmission lines and also enables analog transmission. In order to realize this optical parallel transmission system, it is important to make the light emitting and receiving elements into an array module. In the light emitting / receiving element array module, the pitch of each element is as small as about 200 μm. Therefore, in order to improve the optical coupling between the optical fiber and the device (LD, LED, PD, etc.), various measures have been taken such as processing the lens of the tip of the optical fiber or lens processing of the device chip. .. However, when the signal light is weak, crosstalk is likely to occur. Therefore, in order to eliminate the above-mentioned crosstalk, a light receiving element array module having a structure as shown in FIG. 3 has been proposed. That is,
The light receiving element array 1 is bonded on the circuit board 4 by using eutectic solder such as gold / silicon, gold / tin, gold / germanium, and the like. A microlens array 3 having the same pitch as that of the fiber array 2 (having a lens effect by providing a refractive index distribution in a plate crow by using a method such as ion diffusion) and an optical fiber array 2 are sequentially superposed. ing. Reference numeral 5 is an optical fiber, and 6 is a light receiving element.

[0003]

However, the above-mentioned light receiving element array module has the following problems. That is, 1) When signal light is introduced from the optical fiber 5, the leakage light into the gap between the optical fiber array 2 and the microlens array 3 and the gap between the microlens array 3 and the light receiving element array 1 is Although a leak light can be reduced by applying a non-reflective coating film to the surface of the array No. 3, it was difficult to completely remove the leak light in the microlens array 3. 2) When the light receiving element array 1, the optical fiber array 2 and the microlens array 3 are mounted, a slight (several microns) misalignment increases leakage light and causes crosstalk.

[0004]

SUMMARY OF THE INVENTION The present invention provides a light emitting and receiving element array module which solves the above problems.
In a light emitting and receiving element array module in which a light emitting and receiving element array, a glass plate-shaped microlens array, and an optical fiber array are sequentially stacked, an electrode pattern of a predetermined shape is formed on one surface of the microlens array, and an electrode of the microlens array is formed. The first invention is that the electrodes of the light emitting and receiving element array are flip-chip bonded. That is, gold or solder bumps are arranged on the electrode pattern on the surface of the microlens array, and the electrodes of the light emitting and receiving element array are superposed on and bonded to the bumps. A second invention is that an electrically insulating light absorbing film is formed around the light passage portion on the surface of the microlens array on which the electrodes are formed.

[0005]

According to the present invention, the electrode pattern is formed on one surface of the microlens array. This electrode shape is formed at a position corresponding to each optical axis of the microlens,
The shape of the lead electrode corresponds to each electrode of the light emitting and receiving element array. In such a microlens array,
Since the lens pattern and the electrode pattern can be formed at the same time, the deviation of the optical axis between the lens and the light emitting / receiving element can be reduced, and the light leaked into the microlens array can be reduced. Further, when an electrically insulating light absorbing film is formed around the light passing portion of the microlens array, light other than the light passing portion in the microlens array is absorbed by the light absorbing film, and The leaked light quickly diminishes.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 is a sectional view of an embodiment of a light emitting / receiving element array module according to the present invention. In the figure, 11 is a light receiving element array, 12 is an optical fiber array, 13 is a microlens array, 14 is a microlens, 15 is an optical fiber, 16 is an electrode, and 17 is a bump. The light-receiving element array 11 is composed of an InGaAs-based PIN-PD light-receiving element 21 and has high sensitivity to light having a long wavelength of 1.3 μm. The light-receiving diameter is about 100 μm and the arrangement pitch is the optical fiber array 12. 250μ corresponding to the pitch of
m, has an independent electrode structure, and has 5 to the electrode pad.
The 10 μm thick gold bump 17 is transferred. The microlens array 13 has eight microlenses 14 on a straight line on a glass substrate for a microlens array at a pitch of 250 μm corresponding to the pitch of the optical fiber array 12. The other surface of the microlens array 13 (A
As shown in FIG. 2, the electrically insulating light absorbing film 18 made of molybdenum disulfide is formed around each light passage portion 19 on the −A surface).
By vacuum deposition to a thickness of about 5000Å, and as electrodes 16 to be joined to the light receiving element, nickel 2000Å on the base, then copper 2 μm, gold 2000Å on the surface anti-oxidation layer, evaporated or plated. Attach with. In addition,
The electrically insulating light absorbing film 18 may be formed on the entire surface except the light passing portion 19. The light receiving element array 11 and the microlens array 13 are joined by bonding the gold bumps 17 and the electrodes 16. This bonding can be performed with relative position accuracy of 5 μm or less by aligning while observing the electrode 16 pattern. The optical fiber array 12 and the microlens array 13 are aligned with the optical axis, and are fixed with the organic adhesive 20. By the way, when the electrode area of the light receiving element becomes large, the high frequency characteristics deteriorate, so it is necessary to make the electrode area as small as possible and shorten the leads. In this example, the electrode area was small and the capacitance was small, so that high frequency characteristics of 1 GHz or more could be obtained for each element. The microlens array 1
3 may be used as a part of hermetically sealing the light receiving element circuit. The present invention is not limited to the above embodiments, but can be applied to a light emitting element array module such as a light emitting diode or a semiconductor laser element. In this case, it is desirable to devise a device for releasing heat generated by the light emitting element around the microlens array or the element array.

[0007]

As described above, according to the present invention, in the light emitting / receiving element array module in which the light emitting / receiving element array, the glass plate-shaped microlens array and the optical fiber array are sequentially stacked, one surface of the microlens array is provided. Since the electrode pattern of a predetermined shape is formed and the electrodes of the microlens array and the electrodes of the light emitting and receiving element array are flip-chip bonded, the leakage light in the microlens array,
Further, there is an excellent effect that leakage light between the microlens array and the light emitting / receiving element array can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of a light emitting / receiving element array module according to the present invention.

FIG. 2 is a plan view of plane A of the microarray in the above embodiment.

FIG. 3 is an exploded sectional view of a conventional light receiving element array module.

[Explanation of symbols]

 1, 11 Light-receiving element array 2, 12 Optical fiber array 3, 13 Microlens array 4 Circuit board 5, 15 Optical fiber 6, 21 Light-receiving element 14 Microlens 16 Electrode 17 Bump 18 Electrically insulating light-absorbing film 19 Light passage part 20 Organic adhesive

Claims (2)

[Claims] 1. In a light emitting and receiving element array module in which a light receiving and emitting element array, a glass plate-shaped microlens array and an optical fiber array are sequentially stacked, an electrode pattern having a predetermined shape is formed on one surface of the microlens array, A light emitting and receiving element array module, characterized in that the electrodes of the lens array and the electrodes of the light receiving and emitting element array are flip-chip bonded. 2. The light emitting and receiving element array module according to claim 1, wherein an electrically insulating light absorbing film is formed around the light passage portion on the surface of the microlens array on which the electrodes are formed.