JP2002033505A - Planar photodetector, method of manufacturing it, and device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planar photodetector the characteristics of which are not deteriorated when the photodetector is integrated with an electronic element and which does not require high accuracy for alignment when mounted and has a high-productivity structure. SOLUTION: The planar photodetector 1 receives the light made incident to the surface of a substrate 2. The photodetector 1 is composed of a first substrate 17 which is needed for the formation of the photodetector 1 and removed or thinned in thickness, functional layers 10, 14, 15, and 16 needed for performing light reception and electrical control, and electrodes 8 formed on the surface of the functional layers 10, 14, 15, and 16. The photodetector 1 is stuck to a second substrate 2 in an insulated state and an electric wiring pattern which is used for driving and controlling the element 1 is electrically connected to the electrodes 8 on the second substrate 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-type light receiving element which is easy to manufacture, has a high yield, and is suitable for two-dimensional arraying, a method of manufacturing the same, and an opto-electron fusion in which the surface-type light receiving element is integrated with a Si integrated circuit. The present invention relates to a device, an optical wiring device using the device, and the like.

[0002]

2. Description of the Related Art At present, an optoelectronic integrated device in which a high-speed two-dimensional array type surface light receiving element and a Si-IC (Integrated Circuit) are integrated for application to large-capacity parallel optical information processing and high-speed optical connection. The development of is desired.

[0003] As a surface type light receiving element, a pin photodiode formed by laminating a p-type layer, an undoped light absorbing layer, and an n-type layer on a semiconductor substrate such as GaAs or Si, or a semi-insulating substrate. MSM (Metal-Semiconducto) with an undoped light absorbing layer formed and a comb-shaped Schottky electrode formed on its surface
r-Metal) photodiode.

In the case of integration with a Si-IC, a method has been devised in which the growth substrate on which these light-receiving elements are manufactured is removed, only the optical functional layer is thinned, and the film is transferred to a substrate on which the Si-IC is formed. Have been. The method of bonding the thinned light-receiving element to another substrate in this way can improve the product yield because each element is optimally designed and manufactured by the optimal process method, and only non-defective products are combined and integrated. so,
In addition, there is an advantage that a surface process after bonding is possible.

[0005] An example of such integration is disclosed in Japanese Unexamined Patent Publication No.
As disclosed in JP-A-223848, a thin film is formed on the electronic integrated circuit substrate 200 via an insulating film 300 such as polyimide.
There is one in which a pin photodiode is bonded to form a wiring pattern. FIG. 12 shows a cross-sectional view thereof. On the integrated circuit substrate 200, a p-GaAs layer 1130 and an i-GaAs light absorbing layer 1
A photodiode 107 consisting of an n-GaAs layer 1131 is bonded with a polyimide film 300 via an insulating film 1132. The p-side electrode of the photodiode is 1113 and the n-side electrode is 400. The wiring pattern 200A is formed and used as an array electrode. 1100G is a light entrance window of the photodiode. Since 1000 is a light emitting element, description thereof is omitted.

In such a structure, for example, after forming a surface electrode by epitaxially growing the above-mentioned pin structure on a GaAs substrate, the surface is adhered to a glass substrate or the like with wax, and the GaAs substrate is removed by wet etching. Then, the substrate is adhered to an integrated circuit substrate, and after removing the glass substrate, a wiring pattern can be formed by a surface process.

[0007] There is also one disclosed in JP-A-06-151946. That is, an electrode 500 having a comb-shaped portion 500a as shown in FIG. 13A is formed on a surface on which a lift-off AlAs etching layer having a high etching rate and an undoped GaAs light absorbing layer are formed on a GaAs substrate. As an MSM photodiode, there is also a method of aligning and bonding an electrode pad 501 ′ formed in advance on another substrate S1 and the electrode pad 501 on the element side as shown in FIG. 13B. In this case, hydrofluoric acid is used for AlAs
Only the layer is etched to separate the GaAs substrate and the optical functional layer F, and only the optical functional layer F is transferred to the substrate S1, and the antireflection film A is formed on the surface.

[0008]

However, in the example of Japanese Patent Application Laid-Open No. 9-223848, the polyimide film 30
Since 0 is between the optical element and the Si substrate 200 and there is a step when forming an electrode wiring pattern, it is necessary to form an electrode by CVD or the like with good step coverage. Also, since only the functional layer of the optical element is transferred to the Si substrate 200 and then the optical element is further processed, considering the damage to the IC, the degree of freedom of the process, that is, the temperature, plasma processing, and the like are limited. Therefore, the form of the optical element is also limited.

On the other hand, in the example of Japanese Patent Application Laid-Open No. Hei 6-151946, the electrodes 501 and 501 'on the wiring pattern formed in advance are arranged.
Is directly bonded, so that it is not necessary to form an electrode to cover the step. However, since electrode alignment is required, there is a problem that the accuracy is required and the cost is increased.

In view of these problems, an object of the present invention is to
When integrating a surface-type light receiving element with an electronic element, the characteristics of the surface-type light-receiving element are not degraded and high precision is not required for alignment at the time of mounting, and the surface-type light-receiving element having a highly productive structure. A manufacturing method and an apparatus using the same.

[0011]

According to a first aspect of the present invention, there is provided a surface-type light receiving element for receiving light incident on a substrate surface (typically, light incident perpendicularly on the substrate surface). A surface-type light-receiving element, wherein a first substrate serving as a holding substrate required for forming the surface-type light-receiving element is removed or thinned, and a functional layer necessary for performing light reception and electrical control; An electrode formed on at least one surface of the functional layer, and a second substrate different from the first substrate,
An electrical wiring pattern for driving and controlling the surface light receiving element is electrically connected to the electrode on the second substrate so that electrical contact cannot be obtained (that is, in an insulating state). It is characterized by being formed. According to such a configuration, typically, the semiconductor substrate before transferring the functional layer constituting the light receiving element is used as a holding substrate, and after performing a process such as electrode formation, the semiconductor substrate is bonded to another substrate. After removing or thinning the substrate, a wiring pattern is formed by a surface process such as photolithography. Therefore, it is possible to provide an optoelectronic integrated device with high productivity without deterioration of the surface light receiving device. That is, when the light receiving element is bonded to another substrate and integrated, the alignment accuracy with the electrode of the lower substrate is not required, and the optical function layer transfer type without any complicated process after further bonding and integrating. Can be realized.

A specific example of the configuration will be briefly described with reference to FIG. As shown in FIG. 1 (a), electrodes of an MSM photodiode are formed first, and for example, an AlN ceramic substrate 2 is used as another substrate, and the functional layer 7 of the light receiving element has a surface on which the electrodes are formed facing downward. And bonded with a thermosetting resin or the like (FIG. 1 (d)). The wiring pattern from the electrode is formed by patterning after removing the substrate as shown in FIG. 2, but it is sufficient to cover the step formed by the mirror layer 10 having a thickness of about 1 μm. .
Si-IC can be flip-chip mounted on the same AlN substrate in a bare chip state after the above-described optical element transfer process, and can be made into an opto-electron fusion MCM (Mu1ti-Chip-Modu1e). The optical device may be transferred to the Si substrate on which the IC is manufactured, but the method of individually manufacturing the Si-IC and the optical device and finally hybrid mounting on the same substrate is a process optimization, yield, crosstalk It is considered that it is excellent from the viewpoint of. MC equipped with such a light receiving element
By providing M, an optical interconnection device that can be performed by optical transmission when wiring between boards or the like can be manufactured at low cost, and a high-density MCM in which ICs are three-dimensionally stacked can be provided. Details will be clarified in the description of the embodiment below.

The following forms are possible based on the above basic configuration. A plurality of the surface-type light receiving elements are provided in the second
And an electric wiring pattern for independently driving and controlling the surface-type light receiving element may be formed on the second substrate.

[0014] The electrode formed on at least one surface of the functional layer is on the side of the adhesive surface with the second substrate, and a part of the functional layer is removed to expose a part of the electrode. The electrical wiring pattern may be formed on the second substrate so that a proper contact is obtained. Thereby, the production yield is improved.

The electrode formed on at least one surface of the functional layer is on the outermost surface after the transfer of the functional layer, and an electric wiring is provided on the second substrate so that an electrical contact can be obtained with a part of the electrode. A pattern can be formed. When electric wiring is formed on the second substrate after bonding, a part of the electrode formed on the outermost surface of the functional layer can be electrically contacted, so that the production yield is improved.

[0016] The second substrate may be an insulator substrate.
This simplifies the wiring pattern forming process when the two-dimensional array is formed. That is, when a plurality of the above-mentioned surface light-emitting elements are integrated in an array, insulation between the elements can be obtained, and a structure with high productivity can be provided without deteriorating the characteristics of the surface light-receiving element.

[0017] An insulating layer may be provided between the second substrate and the functional layer. Forming an insulating film on the surface of the second substrate also simplifies the process of forming a wiring pattern in a two-dimensional array.

[0018] The second substrate may be transparent to a wavelength of light to be received. Light is incident from the back of the substrate in which the surface-type light receiving element is integrated with the electronic element, so that a three-dimensionally stacked highly integrated optoelectronic circuit can be easily realized. That is,
When the second substrate is a transparent substrate, light can be incident from the back surface of the second substrate, and three-dimensional stacking is facilitated.

A surface-type light receiving element is formed by an MS in which two-pole comb-shaped electrodes are alternately arranged only on one surface of the functional layer.
As M (Metal-Semiconductor-Metal) photodiode,
Light can be incident from the surface without the electrode and received. As a result, a high-speed, high-efficiency surface-type light receiving element in which an MSM photodiode and an electronic element are integrated can be realized.
In addition, the light receiving efficiency is increased by making the light receiver an MSM photodiode and inputting light from a surface where no electrode is formed.

Further, the surface type light receiving element is a pin photodiode in which two comb-shaped electrodes are alternately arranged only on one surface of the functional layer, and light is incident from the surface without the electrode. To receive light. This allows
A high-speed, high-efficiency surface-type light receiving element that integrates a pin photodiode and an electronic element can be realized. Further, when the light receiver is a planar type pin photodiode and light is incident from a surface on which no electrode is formed, the light receiving efficiency is increased.

Further, the surface light receiving element may be a pin photodiode having an anode and a cathode formed on both surfaces of the functional layer, respectively. By making the photodetector a stacked pin photodiode, the fabrication process is simplified.

The functional layer may include a multilayer reflection mirror. By providing the multilayer mirror, the light absorption efficiency can be increased and the light receiving efficiency can be increased.

Furthermore, a photo-electron fusion MCM (Multi-Chip-Module) of the present invention that achieves the above object includes the above-mentioned surface light receiving element, and drives and controls the surface light element on the second substrate. A bare chip of a Si integrated circuit for flip chip mounting and integrated with the surface type light receiving element. As a result, the Si-IC and the planar optical element can be miniaturized and integrated, and a highly productive opto-electronic integrated MCM capable of converting an optical signal into an electric signal and receiving the signal can be realized.

According to another aspect of the present invention, there is provided a photo-electron fusion MCM (Multi-Chip-Module) which includes the above-described planar light receiving element, wherein the second substrate is made of Si, and drives the planar optical element. ,
A Si integrated circuit for controlling is formed on the second substrate and is integrated with the surface type light receiving element. The productivity can be increased by manufacturing a Si integrated circuit for driving and controlling the surface light receiving element on the second substrate.

Further, in the optical wiring device of the present invention, which achieves the above object, an optical waveguide medium such as an optical fiber is fixed with a resin adhesive or the like substantially perpendicularly to the surface of the surface-type light receiving element of the photoelectron fusion MCM. Thus, light reception can be performed via the optical waveguide medium. Thus, a low-cost optical wiring device can be provided, and an optical wiring device can be realized using an MCM in which the above-described surface-type optical element and electronic element are integrated.

Further, a multilayer photoelectron fusion MCM of the present invention that achieves the above object includes the above photoelectron fusion MCM, and sandwiches a flattened interlayer insulating layer on at least one surface of the photoelectron fusion MCM, and further comprises A plurality of photoelectron fusion MCMs are stacked so as to constitute a photoelectron fusion MCM including a light emitting element, and it is configured so that transmission and reception of signals between at least two layers can be performed using light. I do. This enables a high-performance multilayer opto-electronic fusion MCM capable of high-speed processing
Can be provided.

Furthermore, a multilayer photoelectron fusion MCM of the present invention that achieves the above object includes the above photoelectron fusion MCM, uses an insulating thin film as a second substrate of the photoelectron fusion MCM, and includes a photoelectron fusion MCM including a light emitting element. In addition, a plurality of photoelectron fusion MCMs are stacked, and signals are transmitted and received between at least two layers by using light.
This also enables high-performance multilayer optoelectronics capable of high-speed processing.
MCM can be provided.

Further, a method of manufacturing a surface-type light-receiving element according to the present invention, which achieves the above object, comprises a step of forming a functional layer on the first substrate, Processing, bonding the surface side of the functional layer to the second substrate, removing or thinning the first substrate to transfer only the functional layer, and forming an electrode on the functional layer surface or the bonding surface side. Forming an electric wiring pattern between the first substrate and the second substrate. This makes it possible to provide a process with high productivity and a high yield for integrating the above-mentioned surface-type optical element and electronic element.

The method of manufacturing a surface-type light-receiving element according to the present invention, which achieves the above object, comprises the steps of: forming a functional layer on the first substrate; Processing, bonding the surface of the epitaxial layer to the third substrate, removing or thinning the first substrate to leave only the functional layer, and bonding the functional layer to the second substrate Removing the third substrate and transferring a functional layer to the second substrate; and forming an electric wiring pattern between the electrode on the functional layer surface or the adhesive surface and the second substrate. And a step. This also provides a highly productive and high-yield process for integrating the planar optical device and the electronic device as described above.

In these methods of manufacturing a surface light receiving element, the method further includes a step of removing a functional layer between the elements of the surface light receiving element to perform element isolation, or a method of manufacturing a surface light receiving element on the first substrate. Forming the first functional layer,
A step of forming an etching stop layer for selectively etching the substrate between the substrate and the functional layer, wherein the etching of the substrate is stopped at the etching stop layer in the step of removing the first substrate. You can do it.

In the step of forming a functional layer of a surface light receiving element on the first substrate, the surface of the first substrate is made porous and then annealed to cover only the surface with porous holes. And a step of epitaxially growing the surface of the first substrate. The first substrate is peeled off from the porous layer of the first substrate by mechanical impact after bonding to the second or third substrate, and the remaining By etching the porous layer, only the functional layer can be transferred.

Further, in the method of manufacturing an opto-electron fusion MCM according to the present invention, which achieves the above object, a planar light receiving element is bonded to a plurality of locations on the second substrate, and the first substrate is removed or thinned. Transferring the functional layer to the second substrate, performing a process of collectively performing electrode wiring for each surface-type light receiving element after the transfer, and finally dicing the second substrate to form the photoelectron fusion MCM. Are manufactured in a single step. Thus, when integrating the above-described surface-type optical element and electronic element, a plurality of MCMs can be collectively manufactured on a large-area substrate to improve productivity.

In the method of manufacturing the photoelectron fusion MCM,
A plurality of surface light receiving elements are sequentially bonded in an array at a plurality of places on the second substrate, or a plurality of surface light receiving elements are formed at a plurality of common places on the first substrate, The second
The surface-type light receiving elements can be collectively bonded to a plurality of corresponding locations on the substrate, and the first substrate can be removed or thinned.

Further, the method may further include a step of sequentially flip-chip mounting the Si integrated circuits at a plurality of corresponding locations on the second substrate in an array.

[0035]

Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1] A first embodiment of the present invention is as follows.
MSM (Metal-Se
In this example, only a functional layer including an absorption layer and a mirror layer is transferred to a ceramic substrate (such as AlN) having good thermal conductivity using a semiconductor-metal (photodiode) 1. FIG. 1 shows a sectional view and a perspective view thereof.

First, FIGS. 1 (a) and 1 (b)
3 shows a structure of an MSM photodiode formed on a GaAs substrate 17 before transfer to a GaAs substrate 17. In this structure, 7 is Ga
As a functional layer including an absorption layer and a mirror layer, 4 is a light receiving region formed by combining comb electrodes 8 as shown in FIG.
Is an electric wiring on the side to be a common electrode, 3 is an electrode pad as the other electrode, and in FIG. 1, it has a 2 × 4 two-dimensional array structure. Of course, the number of arrays is not limited, and they may be arranged one-dimensionally in one row.

The surface side of such a normal MSM photodiode 1 is turned downward and adhered to the AlN substrate 2, the GaAs substrate 17 is removed, and only the functional layer 7 of the photodiode is removed as shown in FIG. Is transferred to another substrate 2. At this time, no wiring for obtaining electrical contact with the photodiode is formed on the substrate 2 side, and when bonding the front side of the MSM photodiode 1, rough alignment is sufficient. To perform electrical wiring, the functional layer
The peripheral portion is etched to expose only a portion of the electrode wiring 5 and the electrode pad 3 formed on the surface of the MSM photodiode 1 so that only the region indicated by the broken line 6 in FIG. Let it. After the GaAs substrate 17 is removed, a wiring pattern is formed by a surface process so that it can be connected to another device or power supply. Reference numeral 10 denotes a dielectric multilayer mirror for increasing the light absorption efficiency, which will be described later.
It is left unetched. Reference numeral 12 denotes an isolation groove for reducing crosstalk between elements described later.

FIG. 1D is a cross-sectional view after the transfer (FIG. 1D).
(C) Cross section along the dashed line). An Al ₂ O ₃ / AlN or SiO ₂ / Mg is formed on the AlN substrate 2 by a thermosetting resin adhesive 13.
DBR mirror 10 composed of an O multilayer film, comb-shaped electrode 8, insulating film 16 for insulating electrical wiring and electrode pads, i-GaAs layer 15 serving as a light absorbing layer, DBR mirror 14 composed of an AlAs / AlGaAs multilayer film Function layer 7 of MSM photodiode 1 composed of
Is glued. The element isolation groove 12 is flattened with polyimide. In such a structure, the comb-shaped electrode 8 for Schottky contact does not become a shadow when light enters as shown in FIG. 1D, so that the light absorption efficiency increases. Also,
Since the resonator is formed by the DBR mirrors 10 and 14, the light confinement efficiency is improved, and the light absorption efficiency is also improved.

On the other hand, FIG. 2 shows an example of the electric wiring after the transfer of the functional layer 7. After the transfer of the functional layer, a wiring pattern 21 is formed using photolithography so as to be electrically connected to the electrode pad 3 and the electric wiring 5 of the MSM photodiode 1. At this time, the Si-IC bare chip 20
Are flip-chip mounted on the same AlN substrate 2 to form an optoelectronic integrated circuit board. In this case, as the Si-IC 20, a transimpedance amplifier or a comparator for amplifying a signal from the light receiver 1 and a logic IC connected to a subsequent stage are mounted. Thus, the wiring capacity is reduced, high-speed driving is enabled, and a small receiving module (for the receiving side of optical communication), a logic circuit that can be optically connected, and the like can be configured. Thus, the optical element 1 and the Si-I
A photoelectron MCM in which C20 is formed on the same substrate 2 can be realized.

In this embodiment, the structure in which the Si-IC 20 is hybridized by flip-chip mounting has been described.
-The substrate on which the IC is manufactured may be used as the substrate 2 and the light receiving device may be transferred to a region where the IC is not formed. In this case, a portion indicated by reference numeral 20 in FIG. 2 corresponds to a region where the IC is manufactured.

Next, the manufacturing process will be described with reference to FIG. 3A, a multilayer DBR mirror 14 made of undoped AlAs / AlGaAs and an undoped GaAs absorption layer (thickness: 1 μm) are epitaxially grown on a GaAs substrate 30 to form a SiN insulating film 16 and then a window. It is opened to form a comb-shaped electrode 8 which becomes a Schottky junction with Ti / Au, and a dielectric multilayer mirror 10 made of AlN / Al ₂ O ₃ or SiO ₂ / MgO is formed on the entire surface by sputtering or the like. Film.

In FIG. 3B, AlN is applied by the adhesive 13.
The dielectric mirror 10 is attached to the substrate 2. At this time, a thermosetting resin was used as the adhesive, but a UV curable resin may be used. In addition, either an insulating or conductive adhesive may be used. Furthermore, besides the adhesive, a metal film is formed on both bonding surfaces and bonded by solder bumps,
Pressure bonding between metals may be performed. Solid phase bonding by thermocompression bonding is also possible. Substrate 2 is also made of Al
Other than the N substrate, a Si substrate, a glass substrate, a glass epoxy printed circuit board, or the like may be used.

In FIG. 3C, GaAs was mixed with NH ₃ + H ₂ O ₂ mixed solution.
The substrate 30 is removed by etching. At this time, AlAs of the first layer of the DBR mirror 14 does not dissolve in the etchant, so that complete selective etching is possible. However, since this AlAs layer changes with time due to oxidation, it is desirable that only one layer of AlAs be etched with HCl to make the AlGaAs layer the outermost surface. In addition, although the removal of the substrate 30 is performed by etching, the substrate 30 may be thinned by using in combination with polishing or by polishing alone. Next, in order to expose the electrode 8, only the periphery of the transferred functional layer is etched with sulfuric acid + hydrogen peroxide, and the insulating film 16 is subsequently removed with a hydrofluoric acid-based etchant. At this time, the element isolation groove 12 is also formed at the same time.

In FIG. 3 (d), an electric wiring 2 made of Ti / Pt / Au which can make contact with the electrode 8 of the MSM photodiode.
1 is formed by a lift-off method using photolithography. The wiring pattern can be formed by a vapor deposition method, or can be formed by plating or a CVD method.

An MSM in which the functional layer prepared here is transferred.
In the photodiode 1, the light receiving area is set to 20 μm and the element interval is set to 250 μm. However, the present invention is not limited to this.

In the present embodiment in which GaAs is used as the absorption layer 15, high efficiency and high speed (10 G
(Up to about Hz). Although the mirrors 10 and 14 are provided above and below the light absorbing layer 15 to increase the light receiving efficiency, it is not always necessary. In that case, the incident surface
It is desirable to apply an AR (antireflection) coating.

[Embodiment 2] A second embodiment of the present invention is as follows.
A light transmitting body such as a glass substrate or a resin substrate is used as the mounting substrate on the transfer side, and light is incident from the back surface of the substrate 43 as shown in FIG. In this case, the Schottky electrode 8 is on the front side, the GaAs substrate 17 on which the MSM photodiode is formed is removed first, and the removed surface is bonded to the transparent substrate 43.

The steps will be described briefly with reference to FIG.
In FIG. 4A, an MSM photodiode is manufactured in the same manner as in the first embodiment. In FIG. 4B, the surface of the MSM photodiode is attached to a quartz substrate 40 using an adhesive 41. In FIG. 4C, as in the first embodiment, the GaAs substrate 17 is removed by etching or the like to form the electrode separation groove 12 as well. Fig. 4 (d)
In the above, the quartz substrate 40 is bonded to the substrate 43 with a light-transmitting adhesive 44, and the quartz substrate 40 is removed by melting the adhesive 41.
The electric wiring 21 is manufactured by the surface process in the same manner as in the first embodiment. At this time, the insulator 42 is formed around the functional layer so that the functional layer and the electric wiring 21 do not come into contact with each other.

In the case of such a structure, a light-emitting element corresponding to the above-mentioned light-receiving element is arranged under the substrate 43 to form a stack, so that optical interconnection between the opto-electronic MCMs becomes possible.

In the above embodiment, the GaAs layer was used as the absorption layer.
A similar structure can be realized by using an nGaAs layer as an absorption layer.

[Embodiment 3] In the embodiments up to this point, an example was given of a compound semiconductor such as GaAs. However, a similar structure can be realized with a Si film. The arrangement, structure, and the like can be formed in exactly the same manner as in FIG. 1, but the constituent materials and processes are slightly different. This third embodiment will be described briefly.

First, the configuration of the comb-shaped electrode is shown in FIG.
FIG. 5 (a) ′ shows the configuration of the section BB ′ of FIG. This substrate is a Si substrate 50 including a porous Si layer 51 so that the functional layer can be easily removed later. An Si epitaxial layer 52 (1 μm thick) is formed on the porous Si layer 51. To fabricate such a substrate, first, the surface of the Si substrate is anodized in a hydrofluoric acid-based solution to make it porous, and then annealed in hydrogen at a high temperature to close the porous pores only on the surface, and CVD The epitaxial growth of Si may be performed by a method or the like.

[0055] The surface of the Si epitaxial layer 52 is thermally oxidized Si0 ₂
After the layer is obtained, a Pt electrode is formed by opening a window by removing the SiO ₂ layer only in a portion where a Schottky contact is obtained, and further annealing is performed to silicide the interface to obtain a Pt ₂ Si layer. As a result, as shown in FIG. 5A ′, the SiO ₂ layer 53 and the Pt / P
The cross-sectional structure is such that the t ₂ Si layers 54 are alternately arranged (Pt / P
The reason why the t ₂ Si layer 54 is drawn slightly on the Si epi layer 52 side is that silicidation occurs on the Si epi layer 52 side). Note that the element isolation groove 56 is formed by etching before forming the thermal oxide layer. On the electrode, a SiO ₂ / MgO dielectric multilayer mirror 55 is formed as in the first embodiment.

[0056] In FIG. 5 (b), leave the top surface of the dielectric mirror 55 on Si0 _2, and Si0 ₂ of the Si substrate 57 and the Si-MSM photodiode of the surface bonding by solid phase bonding.

Next, in FIG. 5C, the Si substrate 50 when the MSM photodiode was manufactured was peeled off by mechanical impact utilizing the low mechanical strength of the porous Si layer 51, and remained by wet etching. Porous Si
Layer 51 is completely removed. Thereafter, if electrode wiring is formed in the same manner as in the first embodiment, a low-cost photodiode mainly composed of a Si material can be obtained. Of course, a substrate other than the Si substrate may be used as the substrate 57.

The response wavelength range is almost the same as GaAs, about 900 nm from the visible range, and the response speed is about 1 GHz, which is inferior to GaAs, but has advantages in terms of cost reduction, material safety, etc. .

Although the MSM photodiode using the Si absorption layer 52 has been described above, a pin type photodiode may be used with a similar structure. FIG. 6 is a cross-sectional view of a comb-shaped electrode corresponding to FIG. Instead of forming a Schottky electrode, an n-type diffusion layer 60 and a p-type diffusion layer 61 are formed from a window-opened region of the thermally oxidized silicon layer 53 to form an ohmic electrode 54, and p (p Diffusion layer 6
1) A -i (Si epilayer 52) -n (n-type diffusion layer 60) junction may be made.

[Embodiment 4] A fourth embodiment of the present invention is as follows.
It has a function of transferring a functional layer of a pin photodiode using a compound semiconductor. The layer configuration is slightly different from the first embodiment,
As shown in FIG. 7, p-AlAs / AlGaAs multilayer DBR mirror 7
4. The i-GaAs absorption layer 73 and the n-AlAs / AlGaAs multi-layer DBR mirror 72 have a pin structure formed by crystal growth, and the multi-layer mirrors 72 and 74 are both upper and lower epitaxial mirrors.

The electrodes are formed on the upper and lower sides, and the p-electrode 77 is Ti / Pt / Au formed on the outermost surface of the epitaxial layer 74. The electrode pad 76 formed on the AlN substrate 2 with its side inverted. Are bonded with Au / Sn solder (not shown). Note that a highly doped GaAs layer (not shown) is formed on the outermost surface of the epitaxial mirror 74 to reduce the contact resistance. At this time, the p-electrode 77 is a solid electrode common to the arrayed pin photodiodes, and the alignment with the electrode pad 76 on the substrate 2 does not require any precision.

The n-electrode 70 is formed on the surface of the epitaxial mirror 72 that appears after removing the GaAs substrate after transferring the functional layer. At this time, a contact is made with a highly doped GaAs layer (not shown) in order to lower the contact resistance. The light intake window 71 is 200 μm
It is formed by φ.

The electric wiring 21 may be formed in the same manner as in the second embodiment. In the pin photodiode in which the anode and the cathode are formed on both sides of the functional layer as described above, the response speed is slower than that of the MSM type of the first embodiment. Cost can be reduced.

[Embodiment 5] In the embodiments described so far, one MC
Although the process of M has been mainly described, it is desirable that a batch process can be performed at a wafer level in order to increase productivity. FIG. 8 shows a conceptual diagram for that purpose. In this embodiment,
A low-cost Si substrate is used. On a Si substrate 80, regions 81 on which elements are mounted are arrayed at a specific pitch.

First, a marker is formed for each wafer in an area 81 on the Si substrate 80 where the surface-type light receiving element is to be mounted, and a required number of arrays of light receivers 84 are cut out from the GaAs substrate 83, and the die bonder device is used. This is sequentially implemented according to the marker. At this time, if the marker area is formed by photolithography, an array can be formed with photomask accuracy, and mounting can be performed with high accuracy by pattern matching of the die bonder device, so that the subsequent electrode pattern forming step is also easy.

Next, the GaAs substrate of the photodetector 84 is removed by etching at the wafer level. At this time, a region that is not etched and an end of the light receiver 84 may be protected with a resist so as not to be damaged. The electrical wiring is formed again by the photolithography process as in the first or second embodiment. At this time, etch the GaAs substrate
The thickness of the functional layer of the photodetector 84 remaining on the surface of the Si substrate is 3
Since it is about μm, batch surface processing by photolithography is possible.

By sequentially mounting the Si-ICs 85 where the electrode wirings thus formed are required, an MCM assembly substrate is completed. Finally, a single MCM is obtained by dicing the Si substrate 80 as shown by a broken line 82.

Through the above steps, an optoelectronic MCM substrate can be provided at a very low cost.

In the case of the MSM on the relatively inexpensive Si substrate 57 of the third embodiment, the Si substrate 5 on which the MSM photodiode was manufactured was used.
7 and the Si substrate 80 for the support substrate are made the same size, and the respective MSM photodiodes are adhered to each region 81 in a wafer unit without dicing, and the etching is performed while leaving only the necessary functional layer region. It may be performed. In this case, the process is simplified, and the cost can be further reduced. In this case, the MSM photodiodes need only be formed in necessary regions, that is, only at positions corresponding to the region 81 where the elements are mounted, instead of arranging all the arrays at high density.

Although a semi-insulating substrate was used as the Si substrate 80 used in this embodiment in order to maintain the insulation between the elements, a normal Si substrate was used.
An insulating film may be formed on the surface of a region where insulation is required (for example, a region where the Si-IC 85 is mounted) using a substrate. Further, an insulating ceramic substrate such as AlN used in the first embodiment may be used.

[Embodiment 6] A sixth embodiment of the present invention is as follows.
The present invention relates to an apparatus for performing optical wiring using an MCM to which a functional layer of a surface optical device is transferred.

In FIG. 9, reference numeral 94 denotes an MCM in which a photodetector array 95 and a Si-IC 96 are mounted as in the first embodiment, and a ribbon fiber 93 in which four optical fibers are bundled.
A member 91 for fixing the end face of the photodetector 95 is directly adhered to the input end of the light receiver 95 with a UV curable resin in alignment with the MCM 94. The member 91 has holes 92 for fixing a plurality of optical fibers at equal intervals. After fixing the fibers in the holes 92, the member 91 and the optical fibers are simultaneously polished to obtain a flat surface. The material of the member 91 is glass, resin,
Si is suitable. Further, a quartz fiber may be used as the optical fiber, but a plastic optical fiber (POF) that does not require alignment accuracy is suitable for short-distance transmission. In particular, a POF having a perfluorinated polyimide as a core can be used in a wide wavelength band from 0.6 μm to 1.3 μm, and is used here.

On the other hand, reference numeral 90 denotes an MCM on which a light emitting element is similarly mounted instead of a light receiver, and a member 91 for fixing the end face of the ribbon fiber 93 is also directly bonded with resin. As the light emitting element, a surface emitting laser is most suitable, but an edge emitting laser or a light emitting diode may be used. In addition, the material system also depends on the signal speed and wavelength band,
Either Si or InGaAs can be selected.

The connection from the MCMs 94 and 90 to the motherboard can be made by attaching / detaching using the connector pins 97, soldering, flip-chip mounting, etc., and can be used as a connection between boards in an electronic device. Therefore,
When the distance is short, an arrayed optical waveguide film made of resin may be used instead of the optical fiber.

For alignment, see MCM94,
An alignment mark 98 is formed on the substrate on the 90 side,
Low-cost optical mounting is possible by passively aligning optical fibers and the like. Alternatively, use a metal film of MCM9
A method may be used in which the guide members are formed on the end faces of the array optical fibers 4 and 90 and bonded by self-alignment via solder balls, or a method in which a guide member is fixed at the position of an alignment mark.

[Embodiment 7] A seventh embodiment according to the present invention provides:
The MCM to which the functional layer of the optical element has been transferred is three-dimensionally stacked as shown in FIG. An Si substrate 100 having an insulating layer on the surface is used as an original substrate, and a Si-IC bare chip 106 and a surface emitting laser 104 are mounted on the first layer, and the whole is covered with an insulating member 101 to flatten the surface. And then
A contact hole for wiring is formed, a buried electrode material 103 is formed, and a wiring pattern 102 is formed on the insulating layer 101. In the second layer, the surface emitting laser 10
The optical receiver 105 of the present invention for receiving the output from the optical receiver 4 is mounted.

Here, as in the first embodiment, only the functional layer of about 3 μm is mounted on the photodetector 105 by removing the GaAs substrate, and accordingly, the Si-IC 106 is also subjected to the CMP (chem.
The thickness is reduced to about 3 μm by ical mechanical polishing. Also, the light receiver 105
Is of a type capable of receiving light from below as shown in the second embodiment.

In this case, the surface of the Si-IC is turned upward, the Si substrate is thinned by polishing, and the polished surface is mounted on the substrate 100 side by die bonding. It may be electrically connected. On the other hand, when the Si-IC is flip-chip mounted with the electrode surface facing down, the Si-IC 106 and the photodetector 105
The CMP may be performed at a time with the device mounted.

Such stacking is realized by the interlayer insulating layer 107.
Is carried out after forming. Polyimide, PSG, or the like is usually used as the insulating layer 107, but an aramid resin may be used to make the thermal expansion coefficient close to that of the element. With the stacking, signal connection between layers of the multilayer wiring is performed using light. Needless to say, electrical interlayer connection may be used together using the buried electrode 103, and optical connection may be applied to a portion where high-speed transmission or interlayer insulation is required.

In FIG. 10, the layer on which the surface emitting laser is mounted (the first layer in this example) and the layer on which the photodetector is mounted (the second layer in this example) are different layers. A surface emitting laser and a surface light receiving element may be mounted. As a method of manufacturing such a three-dimensional MCM, each layer can be separately formed and finally overlapped. A manufacturing method therefor will be briefly described with reference to FIGS.

For example, the surface emitting laser 111, the light receiving element 112, and the S
The i-IC 113 is mounted, covered with the insulating film 114, flattened, and a contact hole is formed on the surface to form a wiring pattern (wiring is omitted in the drawing). The wiring pattern can be formed on the AlN film 110 in advance. That is, the wiring pattern is changed to the AlN film 110.
Can be formed in advance on the lower surface, and used as a wiring for an element thereunder. Also, each semiconductor element
The thinning by CMP or the like is as described above.

Further, a hole 116 is formed by etching or laser ablation in a portion where connection between layers (both light and electricity) is required, and an electrode material is embedded in a portion where electrical connection is required. When a material transparent to the wavelength of light is used for the insulating film 110 or the like, it is not necessary to make a hole for optical connection. Further, when all are performed by optical connection, it is not necessary to make a hole, and the cost can be reduced by facilitating the work.

In order to configure a module having one function such as a daughter board, it is indispensable to mount L, C, and R passive elements. However, a layer for mounting such passive elements in a multilayer wiring board is also required. They may be provided or these may be mounted on the top layer. Alternatively, a thin-film passive element 115 of the same order (5 μm) as a thin-film semiconductor element may be mounted in the same layer.

After the mounting of each layer, the three-dimensional MCM can be manufactured by stacking on the original substrate 100, heating and pressing to bond the AlN films together. In addition to the AlN film, a film such as a polyimide or an aramid resin may be used. Alternatively, as shown in FIG. 2, each layer may be mounted on an original substrate such as Si, and then the substrate may be thinned by polishing and stacked.

A three-dimensional structure using light for the connection between such layers
The MCM can realize a small high-speed electronic functional element that functions as a motherboard or a daughter board itself for configuring an electronic device.

Further, by using the optical connection, the electromagnetic noise radiated from the substrate can be reduced, so that the cost of noise countermeasures can be reduced. In particular, mobile phones, mobile devices,
It is effective for small portable devices such as notebook PCs, digital cameras and camcorders.

[0087]

As described above, according to the present invention,
When the surface light-receiving element is integrated with the electronic element, the characteristics of the surface light-receiving element are not degraded, high precision is not required for alignment at the time of mounting, and productivity is improved. Also, Si-IC
An MCM capable of receiving a signal by converting an optical signal into an electric signal can be realized by miniaturizing and integrating the surface type optical element. Also,
A highly productive process for integrating a planar optical device and an electronic device can be provided. Further, an optical wiring device can be realized by using an MCM in which the above-described surface-type light receiving element and an electronic element are integrated, or the above-described surface-type optical element and an electronic element are integrated.
A high-performance MCM can be realized by stacking multiple MCMs.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a perspective view, a cross section, and the like of a light receiving element array according to a first embodiment of the present invention.

FIG. 2 is a perspective view illustrating a photoelectron fusion MCM of a first embodiment according to the present invention.

FIG. 3 is a cross-sectional view illustrating a method for manufacturing the light receiving element according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a method for manufacturing a light-receiving element according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a method for manufacturing a light receiving element according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a light receiving element according to a modification of the third embodiment according to the present invention.

FIG. 7 is a sectional view of a light receiving element according to a fourth embodiment of the present invention.

FIG. 8 is a perspective view illustrating a method for manufacturing a photoelectron fusion MCM at a wafer level according to a fifth embodiment of the present invention.

FIG. 9 is a perspective view illustrating an optical wiring device using a photoelectron fusion MCM of a sixth embodiment according to the present invention.

FIG. 10 shows a multi-layer photoelectron fusion device according to a seventh embodiment of the present invention.
FIG. 3 is a cross-sectional view illustrating an MCM.

FIG. 11 is a perspective view illustrating a method for manufacturing a multilayer photoelectron fusion MCM according to the present invention.

FIG. 12 is a cross-sectional view of a conventional functional layer transfer type surface emitting laser array.

FIG. 13 is a diagram illustrating another conventional example of a functional layer transfer type light receiving element.

[Explanation of symbols]

1,84 ... light receiving element 2,43,57,80,100 ... substrate for MCM 3,5,8,54,70,77,500,500a, 501 ... light receiving element electrode 4: light receiving area 6 ... functional layer transfer area 7 Functional layer 10, 14, 55, 72, 74 Reflecting mirror 12, 56 Element isolation groove 13, 41, 44, 300 Adhesive layer 15, 52, 73, 1107, F Light absorbing layer 16, 42, 53, 1132 ... insulating layer 17, 30, 50 ... substrate for manufacturing light receiving element 20, 106 ... IC chip 21, 76, 400, 1113 ... electric wiring (electrode wiring) 40, 200, S1 ... substrate 51 ... porous Layers 60, 61: Impurity diffusion layers 71, 1100G: Light intake window 81: Mounting area 82: Dicing line 83: Light receiving element wafer 85: IC chip 90, 94: Optoelectronic fusion MCM 91: Fixing member 92: Optical waveguide medium end ( Hole) 93 ... Optical waveguide medium 97 ... Continued terminals 98 ... alignment marks 103 ... buried electrode 104,111,1000 ... surface emitting laser 105 and 112 ... light receiving elements 107 and 110 ... interlayer insulating layer 115 ... passive element 1130, 1131 ... contact layer A ... anti-reflective coating

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 31/108 H01L 31/10 G 31/12 27/14 F // H01L 27/00 301 31/10 C F-term (reference) 2H036 JA04 JA05 QA23 QA29 QA56 QA59 2H037 AA01 BA02 BA11 DA03 DA04 DA06 DA11 DA16 DA31 4M118 AA01 AA10 AB05 AB09 BA04 CA02 CA05 CA21 CB02 GA09 GD14 GD20 HA21 HA26 HA29 HA40 5F049 MA05 MB05 RA01 MB05 5F089 AA07 AB13 AB20 AC07 CA20 EA10 FA06 GA10

Claims (25)

[Claims] 1. At least one surface light receiving element for receiving light incident on a substrate surface, wherein a first substrate serving as a holding substrate required for forming the surface light receiving element is removed or thinned, A functional layer necessary for performing light reception and electrical control, and an electrode formed on at least one surface of the functional layer; electrical contact is obtained with a second substrate different from the first substrate; And an electrical wiring pattern for driving and controlling the surface-type light receiving element is formed on the second substrate so as to be electrically connected to the electrode after the bonding. Surface type light receiving element. A plurality of surface light-receiving elements are adhered to the second substrate so as not to make electrical contact with each other, and the surface light-receiving elements are independently driven on the second substrate; 2. The surface-type light receiving device according to claim 1, wherein an electric wiring pattern for controlling is formed. 3. The electrode formed on at least one surface of the functional layer is on the side of the adhesive surface with the second substrate, and a part of the electrode is obtained by removing a part of the functional layer and exposing the electrode. 3. The surface-type light receiving element according to claim 1, wherein the electric wiring pattern is formed on the second substrate so that electrical contact is obtained. 4. The electrode formed on at least one surface of the functional layer is on the outermost surface after the transfer of the functional layer, and is provided on the second substrate so as to obtain electrical contact with a part of the electrode. 3. The surface-type light receiving element according to claim 1, wherein an electric wiring pattern is formed. 5. The surface-type light receiving device according to claim 1, wherein said second substrate is an insulator substrate. 6. The surface light receiving device according to claim 1, wherein an insulating layer is provided between the second substrate and the functional layer. 7. The surface-type light receiving element according to claim 1, wherein said second substrate is transparent to a wavelength of light to be received. 8. An MSM (Metal-Semicond.) Wherein two comb-shaped electrodes are alternately arranged only on one surface of the functional layer.
8. The surface-type light-receiving element according to claim 1, wherein the surface-type light-receiving element is a photodiode (uctor-Metal), and receives light by receiving light from a surface where the electrode is not provided. 9. A pin photodiode in which two-pole comb-shaped electrodes are alternately arranged only on one surface of the functional layer, and light is received from a surface without the electrode by receiving light. 8. The surface-type light receiving element according to any one of 1 to 7. 10. A pin photodiode having an anode and a cathode formed on both sides of the functional layer, respectively.
A surface-type light receiving element according to any one of the above. 11. The surface-type light receiving element according to claim 1, wherein said functional layer includes a multilayer reflection mirror. 12. A bare chip of a Si integrated circuit for driving and controlling a surface-type optical element, which includes the surface-type light-receiving element according to claim 1, and is mounted on the second substrate by flip-chip mounting. A photo-electron fusion MCM (Multi-Chip-Module) characterized by being integrated with the surface type light receiving element. 13. The planar light-receiving element according to claim 1, wherein the second substrate is Si, and the Si integrated circuit for driving and controlling the planar light-emitting element is a Si substrate. A photo-electron fusion MCM (Multi-Chip-Module) manufactured on the second substrate and integrated with the surface light receiving element. 14. The photoelectron fusion according to claim 12, wherein
An optical wiring device, wherein an optical waveguide medium is fixed substantially perpendicular to the surface of a surface-type light receiving element of an MCM so that light can be received through the optical waveguide medium. 15. The photoelectron fusion according to claim 12, wherein
Including the MCM, sandwiching a flattened interlayer insulating layer on at least one surface of the photoelectron fusion MCM, and further constituting a photoelectron fusion MCM including a light emitting element on that surface, a plurality of photoelectron fusion MCMs are stacked, A multilayer optoelectronic fusion MCM, characterized in that transmission and reception of signals between at least two layers can be performed using light. 16. The photoelectron fusion according to claim 12, wherein
Including an MCM, an insulating thin film is used as a second substrate of the photoelectron fusion MCM, a plurality of photoelectron fusion MCMs including a photoelectron fusion MCM including a light emitting element are stacked, and signals are transmitted and received between at least two layers using light. A multilayer optoelectronic fusion MCM characterized in that it is configured to be able to perform. 17. A method of manufacturing a surface-type light-receiving element according to claim 1, wherein a step of forming a functional layer on the first substrate and processing an electrode of the surface-type light-receiving element on the surface of the functional layer. And bonding the surface side of the functional layer to the second substrate,
Removing the first substrate or making it thinner and transferring only the functional layer; and forming an electric wiring pattern between the electrode on the functional layer surface or the adhesive surface and the second substrate. A method for manufacturing a surface-type light receiving element. 18. A method of manufacturing a surface-type light receiving element according to claim 1, wherein a step of forming a functional layer on said first substrate and processing an electrode of said surface-type light receiving element on the surface of said functional layer. A step of bonding the surface of the epitaxial layer to the third substrate, a step of removing or thinning the first substrate to leave only the functional layer, and a step of bonding the functional layer to the second substrate. Removing the third substrate and transferring a functional layer to the second substrate; and forming an electric wiring pattern between the electrode on the functional layer surface or the bonding surface and the second substrate. The manufacturing method of the surface type light receiving element characterized by including these. 19. The method of manufacturing a surface-type light receiving element according to claim 17, further comprising a step of removing a functional layer between elements of said surface-type light receiving element to perform element isolation. 20. An etching stop layer for selectively etching the substrate between the first substrate and the functional layer in the step of forming a functional layer of the surface light receiving element on the first substrate. 20. The method for manufacturing a surface-type light-receiving element according to claim 17, further comprising a step of forming a film, wherein the step of removing the first substrate includes stopping the etching of the substrate at the etching stop layer. 21. The step of forming a functional layer of a surface-type light receiving element on the first substrate, wherein the surface of the first substrate is made porous and then annealed to close the porous holes only on the surface. And a step of epitaxially growing the surface of the first substrate. The first substrate is peeled off from the porous layer of the first substrate by mechanical impact after bonding to the second or third substrate, and the remaining 2. The method according to claim 1, wherein only the functional layer is transferred by etching the porous layer.
20. The method for manufacturing a surface-type light receiving element according to 7, 18, or 19. 22. The photoelectron fusion according to claim 12 or 13.
In the method of manufacturing an MCM, a step of bonding a surface-type light receiving element to a plurality of locations on the second substrate, removing or thinning the first substrate, and transferring the functional layer to the second substrate, A step of collectively forming electrode wiring for each surface-type light receiving element, and finally dicing the second substrate to produce a plurality of the photoelectron fusion MCMs in one step. MCM manufacturing method. 23. The method according to claim 22, wherein a plurality of surface-type light receiving elements are sequentially bonded in an array at a plurality of locations on the second substrate. 24. A planar light receiving element is formed at a plurality of locations on the common first substrate, and the planar light receiving elements are collectively placed at a plurality of corresponding locations on the second substrate. And glue,
23. The method according to claim 22, wherein the first substrate is removed or thinned. 25. The method according to claim 22, further comprising the step of sequentially flip-chip mounting Si integrated circuits in a plurality of corresponding locations on the second substrate in an array. .