JP2014048550A - Light receiving component and manufacturing method for optical receiver module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve highly accurate alignment without making assembly step complex and complicated and without increasing cost.SOLUTION: A light receiving component comprises: a communication photo diode 102 formed on a chip substrate 101; and a plurality of aligning parts 103 formed on the chip substrate 101. The communication photo diode 102 has a light absorption layer 122 formed from semiconductor. The communication photo diode 102 is, for example, a rear incident type in which light is made incident on from the chip substrate 101 side. Light to be made incident on the communication photo diode 102 is transmitted through the chip substrate 101. The aligning parts 103 are composed of a material that blocks the light, and has a hole 131 smaller than the light receiving area of the communication photo diode 102.

Description

  The present invention relates to a light receiving component used for optical fiber communication and a method for manufacturing an optical receiving module.

  In a light receiving device for optical fiber communication, it is desirable that the signal light propagating through the optical fiber is photoelectrically converted without loss at the light receiving portion of the photodiode. For this purpose, it is important that the spot of light emitted from the light emitting end of an optical component such as an optical fiber or a planar optical circuit is within the light receiving surface of the photodiode. For this reason, a condensing lens is generally used between the optical component and the photodiode. In particular, in photodiodes that require high-speed operation, the light receiving area is reduced in order to reduce the junction capacitance, and the need for a condensing lens is increasing.

  On the other hand, multiplexing methods such as WDM (Wavelength Division Multiplexing) have become common with the recent increase in communication capacity. In order to receive such multiplexed optical signals as respective light separated and arranged by an optical filter, the light receiving module is in a state in which a plurality of photodiodes and condenser lenses are arranged (in an arrayed state). ). In such a light receiving module, a photodiode array chip in which a plurality of photodiodes are arranged, a lens array in which a plurality of condensing lenses are arranged, and optical components such as fibers and a planar optical circuit are fixedly mounted. Is formed. When performing these mountings, an alignment process for optimizing the position of each component is important so that the photoelectric conversion of the photodiode has maximum efficiency.

  As described above, when assembling the optical receiver module, both the photodiode array chip and the PLC and space coupling lens connected thereto are provided with alignment marks and fitting structures. There is a method to match the optical axis depending on the accuracy. In this case, for example, since alignment is completed simply by fitting and assembling, the alignment process can be performed in an extremely short time, and the cost can be reduced (see Non-Patent Document 1).

  However, since this alignment relies on mechanical precision, the margin of the photodiode's light-receiving area relative to the spot size of the light incident on the photodiode must be sufficiently large with respect to variations during assembly and mounting. It becomes. For this reason, a practical tolerance cannot be set unless the margin described above is sufficiently large. For example, as described above, if the light receiving area of the photodiode is reduced for speeding up, a sufficient margin cannot be obtained, and the above-described alignment is not practical.

  In contrast to the above-described method, there is a method of performing alignment by setting photodiodes in a light receiving operation state and confirming the intensity of the photocurrent generated by photoelectric conversion at the light receiving portion of each photodiode. In this alignment, since the light intensity is actually detected, for example, sufficient accuracy can be obtained even when the light receiving area of the photodiode is reduced for speeding up.

H. Takahara et al., "Passively Aligned LD / PD Array Submodules by Using Micro-Capillaries", IEEE TRANSACTIONS ON ADVANCED PACKAGING, vol.23, no.2, pp.323-327, 2000.

  However, in the above-described alignment, in order to put the photodiode in an operating state, it is necessary to form a wiring structure for connecting the photodiode and the external power source before the alignment process, and the assembly process is complicated. become. In particular, in the case where the optical component and the lens array are fixed in advance and the photodiode array chip is moved and aligned, the wiring of the power supply connection to each photodiode is complicated. Also, the prior wiring process before fixed mounting is expensive. As described above, the alignment performed with high accuracy has a problem that the assembling process becomes complicated and complicated, resulting in an increase in cost.

  The present invention has been made to solve the above-described problems, and enables alignment with high accuracy without increasing the cost without making the assembly process complicated and complicated. With the goal.

  The light receiving component according to the present invention includes a communication photodiode formed on a chip substrate that includes a light absorption layer made of a semiconductor and transmits light of interest, and a communication photo And a plurality of alignment portions formed on the chip substrate, each having a hole portion having a smaller hole diameter than the light receiving region of the diode.

  The light receiving component may include a mounting substrate on which the chip substrate is mounted and a through hole formed in the mounting substrate corresponding to the hole.

  The light receiving component includes a signal intensity confirmation photodiode formed on a chip substrate with a light absorption layer made of a semiconductor, and an electrode formed on an upper surface of the signal intensity confirmation photodiode, May be formed on the electrode.

  The light receiving component may further include a wiring formed on the chip substrate, and the hole may be formed in the wiring.

  A method of manufacturing an optical receiver module according to the present invention includes a first step of forming a communication photodiode having a light absorption layer made of a semiconductor on a chip substrate through which light is transmitted, and a light blocking material. A second step of forming a plurality of alignment portions on the chip substrate, the first optical waveguide corresponding to the communication photodiode, and the alignment; A third step of forming an optical component in which a second optical waveguide corresponding to the portion is integrally formed, a fourth step of arranging a light detection means with a chip substrate sandwiched between the light emission sides of the optical component, and a second optical The optical component and the chip substrate are aligned so that the alignment light emitted from the waveguide is transmitted through the hole and detected by the light detection means, and the optical component is combined with the chip substrate to form an optical receiving module. And a fifth step.

  The method for manufacturing an optical receiver module may include a sixth step of mounting the chip substrate on the mounting substrate. In the fifth step, the optical component may be mounted on the mounting substrate and the optical component may be combined with the chip substrate.

  As described above, according to the present invention, a plurality of alignment portions that are formed on a chip substrate and are formed of a material that blocks light and have a hole diameter smaller than the light receiving area of the communication photodiode. Therefore, it is possible to obtain an excellent effect that alignment can be performed with high accuracy without making the assembly process complicated and complicated and without causing an increase in cost.

FIG. 1 is a cross-sectional view showing a configuration of a light receiving component according to Embodiment 1 of the present invention. FIG. 2A is a plan view and FIG. 2B is a cross-sectional view showing the configuration of another light receiving component in the first embodiment of the present invention. FIG. 3A is a cross-sectional view schematically showing a state in each step for explaining the method of manufacturing the optical receiver module in the first embodiment of the present invention. FIG. 3B is a cross-sectional view schematically showing a state in each step for describing the method for manufacturing the optical receiver module according to Embodiment 1 of the present invention. FIG. 3C is a cross-sectional view schematically showing a state in each step for describing the method for manufacturing the optical receiver module according to Embodiment 1 of the present invention. FIG. 4 is a cross-sectional view showing a configuration example of an optical receiving module using the light receiving component according to Embodiment 1 of the present invention. FIG. 5 is a cross-sectional view showing a configuration example of an optical receiver module using the light receiving component in Embodiment 2 of the present invention. FIG. 6 is a cross-sectional view showing a configuration example of an optical receiving module using the light receiving component according to Embodiment 3 of the present invention. FIG. 7 is a cross-sectional view illustrating a configuration example of an optical reception module using the light receiving component according to Embodiment 4 of the present invention. FIG. 8 is a cross-sectional view showing a configuration example of a light receiving component and a light receiving module using the light receiving component in the fifth embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
First, Embodiment 1 of the present invention will be described. FIG. 1 is a cross-sectional view showing a configuration of a light receiving component according to Embodiment 1 of the present invention. The light receiving component includes a communication photodiode 102 formed on the chip substrate 101 and a plurality of alignment portions 103 formed on the chip substrate 101.

  The communication photodiode 102 includes a light absorption layer 122 made of a semiconductor. For example, the communication photodiode 102 is formed on the n-type semiconductor layer 121 formed on the chip substrate 101, the light absorption layer 122 formed on the semiconductor layer 121, and the light absorption layer 122. This is a so-called pin type photodiode including the p type semiconductor layer 123. The communication photodiode 102 includes an electrode 124 formed on the semiconductor layer 123 and an electrode (not shown) connected to the semiconductor layer 121. The communication photodiode 102 has, for example, a back-illuminated structure in which light is incident from the chip substrate 101 side. The chip substrate 101 has a function of transmitting light having a target wavelength incident on the communication photodiode 102 (or made of a member).

  The alignment unit 103 is made of the above-described material that blocks light, and includes a hole 131 having a smaller hole diameter than the light receiving region of the communication photodiode 102.

  For example, as shown in FIG. 2, wiring 203, wiring 204, and wiring 205 are formed on the chip substrate 101, and a hole 131 may be formed in the wiring 203 to serve as an alignment portion. Note that the wiring 204 is connected to an electrode 224 formed over the semiconductor layer 123 of the communication photodiode 102. In this example, the electrode 224 is formed in a ring shape so that light can enter the central portion. The wiring 205 is connected to an electrode 225 formed on the semiconductor layer 121 of the communication photodiode 102.

  Next, a method for manufacturing an optical receiver module using the above-described light receiving component will be described with reference to FIGS. 3A to 3C. 3A to 3C are cross-sectional views schematically showing states in respective steps for explaining the method of manufacturing the optical receiver module in the first embodiment. 3A to 3C, the same components as those in FIG. 1 are denoted by the same reference numerals.

  First, as shown in FIG. 3A, a communication photodiode 102 is formed on a chip substrate 101 (first step). For example, an n-type InP layer, a non-doped InGaAs layer, and a p-type InGaAs layer are sequentially formed on a chip substrate 101 made of high-resistance InP by an epitaxial growth method such as a metal organic chemical vapor deposition (MOVPE) method. Next, the p-type InGaAs layer, the non-doped InGaAs layer, and the n-type InP layer described above are processed into a mesa shape by a known photolithography and etching technique, and communication including the semiconductor layer 121, the light absorption layer 122, and the semiconductor layer 123 is performed. The photodiode 102 is used. In addition, electrodes in ohmic contact with each of the semiconductor layer 121 and the semiconductor layer 123 are formed. The electrode 124 is in ohmic contact with the semiconductor layer 123.

  Note that in the case where the communication photodiode 102 is a back-illuminated type that passes through the substrate 101, the electrode (electrode 124) disposed on the upper portion of the element preferably has a configuration that does not transmit light at the center. For example, the electrode 124 may be formed so as to cover the entire area of the semiconductor layer 123 of the communication photodiode 102 (upper part of the element). This is because the signal light incident from the substrate 101 side is reflected by the electrode on the upper part of the element and passes through the light absorption layer made of a semiconductor twice, thereby improving the optical coupling efficiency. . This also applies to other back-illuminated type embodiments described later.

  In addition, a plurality of alignment portions 103 having hole portions 131 having a smaller diameter than the light receiving region of the communication photodiode 102 are formed on the chip substrate 101 (second step). For example, on the main surface of the chip substrate 101, a mask pattern having an opening at a position where the alignment portion 103 is to be formed is formed by known photolithography, and in this state, a metal film made of Au is formed by a vacuum deposition technique. Thereafter, the alignment portion 103 can be formed by removing (lifting off) the mask pattern. If a pattern portion in which a resist corresponding to the hole portion 131 exists is formed in the mask pattern, the hole portion 131 can be formed at the same time in the lift-off process.

  For example, the two alignment portions 103 are provided, and the light receiving portions of the two communication photodiodes 102 are arranged on a straight line passing through the two hole portions 131 in the plan view as shown in FIG. You can do it.

  Next, as shown in FIG. 3B, an optical fiber (first optical waveguide) 302 corresponding to the communication photodiode 102 and an optical fiber (second optical waveguide) 303 corresponding to the alignment unit 103 are integrally formed. The optical component 300 is formed (third step), and the light emitting side of the formed optical component 300 is disposed on the back surface of the chip substrate 101. Here, the optical fiber 302 is provided with a condensing lens 304 to condense light emitted from the optical fiber 302. Similarly, the optical fiber 303 is provided with a condensing lens 305 for condensing light emitted from the optical fiber 303. Also, it is assumed that the arrangement intervals of the condenser lenses, the arrangement intervals of the optical fibers, and the arrangement intervals of the communication photodiode 102 and the alignment unit 103 are the same. The fiber 303 and the condensing lens 305 are easier to manufacture if they have the same structure as the fiber 302 and the condensing lens 304.

  Next, as shown in FIG. 3C, the light detection unit 306 is disposed on the light emitting side of the optical component 300 with the chip substrate 101 interposed therebetween (fourth step). The light detection unit 306 may be, for example, a single photodiode, or may be an image sensor including an imaging tube or a plurality of photodiodes. Thereafter, the optical component 300 and the chip substrate 101 are aligned so that the alignment light 331 emitted from the optical fiber 303 passes through the hole 131 and is detected by the light detection unit 306. In this state, the optical component 300 is combined with the chip substrate 101 to form an optical receiving module (fifth step). Needless to say, the light detection unit 306 is used in the manufacturing process of aligning and does not constitute the light receiving module, and is separated from the light receiving module after manufacturing.

  For example, the alignment light 331 is emitted from the optical fiber 303 and the chip substrate 101 and the optical component 300 are relatively moved while the light detection unit 306 is operated. The chip substrate 101 and the optical component 300 may be fixed with an adhesive or the like at the position where the alignment light 331 is received. In this state, the optical axis (center) of the alignment light 331 emitted from the optical fiber 303 passes through the hole 131.

  In the alignment described above, the positional relationship between the alignment unit 103 (hole 131) and the communication photodiode 102, and the positional relationship between the optical fiber 303 (condensing lens 305) and the optical fiber 302 (condensing lens 304). Are in the same state, the optical axis of the light emitted from the optical fiber 302 also passes through the light receiving central portion of the corresponding communication photodiode 102, and an arrangement with the maximum light receiving efficiency is obtained. In this alignment, the communication photodiode 102 does not need to detect incident light. In other words, the communication photodiode 102 needs to be connected with wiring for connecting to an external power source. There is no.

  The size (hole diameter) of the hole 131 may be determined according to the condenser lens 305 to be used. This is because if the hole 131 is too large compared to the beam diameter of the alignment light depending on the characteristics of the condenser lens 305, the optical axis of the alignment light is not arranged at the center of the hole 131. This is because the light detection unit 306 detects the state of the maximum light reception intensity, and thus cannot determine the center position with high accuracy. The hole diameter of the hole 131 is preferably about the same as the beam diameter of the alignment light. However, the hole diameter of the hole 131 is at least smaller than the light receiving region of the communication photodiode 102.

  More specifically, if the pinhole diameter is too small, the transmitted light intensity is reduced to the detection limit. Therefore, the intensity distribution of the alignment light is regarded as a Gaussian distribution, and is not less than 0.23 times the Gaussian beam radius. It is desirable to be. If the pinhole diameter is too large, the relationship between the detected light intensity of the light detector and the position will be a flat top shape that does not change near the center of the beam at the time of alignment, and calculation processing such as waveform processing is required for beam position adjustment. Since it becomes necessary and the process becomes complicated, it is desirable to suppress it to about twice the beam diameter.

  In addition, a plurality of coarse alignment parts having large holes for coarse alignment and a plurality of fine adjustment parts having small diameter holes for fine adjustment to fix the position accurately are provided. May be. In the case of only the fine alignment portion, since the hole diameter of the hole portion is small, it is not easy to detect this position and it may take time. On the other hand, by providing the coarse alignment unit, it is possible to detect the position of the alignment unit more quickly, and the time required for alignment can be shortened.

  As shown in FIG. 4, each optical fiber is fixed by a fiber block 311, and the condenser lens 304 and the condenser lens 305 are used by being fixed to the condenser lens array substrate 312 by bumps 401. Also good. In this example, the communication photodiode 102 has a configuration in which the direction with respect to the optical component 300 is reversed and light enters from the upper side (upper surface) of the element. In this case, the electrode above the element of the communication photodiode 102 may be formed in a ring shape like the electrode 224 described with reference to FIG. 2, and light may be incident on the central portion. In addition, when the electrode of the element upper part is comprised from the material which permeate | transmits the light of the communication wavelength band to measure, the shape of an electrode is not restrict | limited to a ring shape.

[Embodiment 2]
Next, Embodiment 2 of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view showing the configuration of the light receiving component according to Embodiment 2 of the present invention and the configuration of an optical receiving module using this light receiving component.

  First, the light receiving component includes a communication photodiode 102 formed on the chip substrate 101, and a plurality of alignment portions 103 formed on the chip substrate 101. Similar to the first embodiment, the communication photodiode 102 includes a light absorption layer (not shown) made of a semiconductor. The chip substrate 101 transmits target light incident on the communication photodiode 102. The alignment unit 103 is made of the above-described material that blocks light, and includes a hole 131 having a smaller hole diameter than the light receiving region of the communication photodiode 102. These configurations are the same as those in the first embodiment described above, and the same reference numerals are given to the same configurations.

  The optical receiving module includes an optical component 500 in which an optical fiber (first optical waveguide) 502 corresponding to the communication photodiode 102 and an optical fiber (second optical waveguide) 503 corresponding to the alignment unit 103 are integrally formed. Is provided. Each optical fiber is fixed by a fiber block 511. Further, the condenser lens 504 and the condenser lens 505 are fixed to the condenser lens array substrate 512. The light emitted from the optical fiber 502 is condensed by the condenser lens 504, and the light emitted from the optical fiber 503 is condensed by the condenser lens 505. In addition, the arrangement intervals of the condenser lenses, the arrangement intervals of the optical fibers, and the arrangement intervals of the communication photodiode 102 and the alignment unit 103 are the same.

  In addition, in the second embodiment, the chip substrate 101 of the light receiving component is mounted on the mounting substrate 522. For example, the chip substrate 101 is mounted (flip chip connection) on the mounting substrate 522 by bumps 401 made of AuSn solder or the like. In addition, a through hole 523 is formed in the mounting substrate 522 at a position corresponding to (facing) the hole 131. The mounting substrate 522 is made of, for example, a ceramic substrate and includes wiring made of gold (Au). The wiring is formed by patterning using a known photolithography technique and etching technique. As described above, the mounting substrate 522 on which the chip substrate 101 is mounted and the optical component 500 are assembled by being connected by the fixing block 521.

  In the second embodiment, in the alignment, the alignment light 531 emitted from the optical fiber 503 is incident and transmitted from the back surface of the chip substrate 101, passes through the hole 131, passes through the through hole 523, and is detected. The optical component 500 and the mounting substrate 522 are aligned so that the unit 306 can detect the maximum received light intensity. In this state, the mounting substrate 522 and the optical component 500 are connected (joined) by the fixing block 521 to obtain an optical receiving module.

  Also in the second embodiment, in the alignment described above, the positional relationship between the alignment unit 103 (hole 131) and the communication photodiode 102, and the optical fiber 503 (condensing lens 505) and optical fiber 502 (condensing light). Since the positional relationship of the lens 504) is the same, the optical axis of the light emitted from the optical fiber 502 is also in a state of passing through the light receiving central portion of the corresponding communication photodiode 102, so that the maximum light receiving efficiency is obtained. Is obtained. In this alignment, the communication photodiode 102 does not need to detect incident light. In other words, the communication photodiode 102 needs to be connected with wiring for connecting to an external power source. There is no.

  Note that the alignment accuracy is determined by the hole 131 as in the first embodiment. Therefore, the through hole 523 formed in the mounting substrate 522 is not required to have a fine hole diameter like the hole 131, and has a sufficiently large hole diameter so as not to block the alignment light 531 that has passed through the hole 131. Is important. Note that the through hole 523 may also be used as a through hole for electrical wiring in the mounting substrate 522.

[Embodiment 3]
Next, Embodiment 3 of the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional view showing the configuration of the light receiving component according to Embodiment 3 of the present invention and the configuration of an optical receiver module using this light receiving component.

  First, the light receiving component includes a communication photodiode 102 formed on the chip substrate 101, and a plurality of alignment portions 103 formed on the chip substrate 101. The communication photodiode 102 is the same as that of the first embodiment and includes a light absorption layer (not shown) made of a semiconductor. The chip substrate 101 transmits target light incident on the communication photodiode 102. The alignment unit 103 is made of the above-described material that blocks light, and includes a hole 131 having a smaller hole diameter than the light receiving region of the communication photodiode 102. These configurations are the same as those of the first and second embodiments, and the same reference numerals are given to the same configurations.

  The optical receiving module also includes an optical component 300 in which an optical fiber 302 corresponding to the communication photodiode 102 and an optical fiber 303 corresponding to the alignment unit 103 are integrally formed. Each optical fiber is fixed by a fiber block 311. The condenser lens 304 and the condenser lens 305 are fixed to the condenser lens array substrate 312. The light emitted from the optical fiber 302 is condensed by the condenser lens 304, and the light emitted from the optical fiber 303 is condensed by the condenser lens 305. In addition, the arrangement intervals of the condenser lenses, the arrangement intervals of the optical fibers, and the arrangement intervals of the communication photodiode 102 and the alignment unit 103 are the same. These configurations are the same as those in the first embodiment, and the same reference numerals are given to the same configurations.

  In addition, in the third embodiment, the chip substrate 101 of the light receiving component is mounted on the mounting substrate 622. For example, the chip substrate 101 is mounted (flip chip connection) on the mounting substrate 622 by bumps 401 made of AuSn solder or the like. In addition, a through hole 623 is formed in the mounting substrate 622 at a position corresponding to (facing) the hole 131. The mounting substrate 622 is made of, for example, a ceramic substrate and includes wiring made of Au. The wiring is formed by patterning using a known photolithography technique and etching technique. As described above, the chip substrate 101 mounted on the mounting substrate 622 and the optical component 300 are connected and assembled. In the third embodiment, the back surface of the chip substrate 101 is connected (joined) to the optical component 300. This connection state is the same as in the first embodiment.

  In the third embodiment, in the alignment, the alignment light 331 emitted from the optical fiber 303 is incident and transmitted from the back surface of the chip substrate 101, passes through the hole 131, passes through the through hole 623, and is detected. The chip substrate 101 mounted on the mounting substrate 622 and the optical component 300 are aligned so that the maximum light reception intensity is detected by the unit 306. In this state, the back surface of the chip substrate 101 and the optical component 300 are connected (bonded) to form an optical receiving module.

  Also in the third embodiment, in the alignment described above, the positional relationship between the alignment unit 103 (hole 131) and the communication photodiode 102, and the optical fiber 303 (condensing lens 305) and optical fiber 302 (condensing light). Since the positional relationship of the lens 304) is the same, the optical axis of the light emitted from the optical fiber 302 also passes through the light receiving central portion of the corresponding communication photodiode 102, and is arranged so as to have the maximum light receiving efficiency. Is obtained. In this alignment, the communication photodiode 102 does not need to detect incident light. In other words, the communication photodiode 102 needs to be connected with wiring for connecting to an external power source. There is no.

  Note that the alignment accuracy is determined by the hole 131 as in the first embodiment. Therefore, the through hole 623 formed in the mounting substrate 622 does not need to have a fine hole diameter like the hole 131, and has a sufficiently large hole diameter so as not to block the alignment light 331 that has passed through the hole 131. Is important. Note that the through hole 623 may also serve as a through hole for electrical wiring in the mounting substrate 622.

[Embodiment 4]
Next, Embodiment 4 of the present invention will be described with reference to FIG. FIG. 7 is a cross-sectional view showing the configuration of the light receiving component according to the fourth embodiment of the present invention and the configuration of an optical receiving module using the light receiving component.

  First, the light receiving component includes a communication photodiode 102 formed on the chip substrate 101, and a plurality of alignment portions 103 formed on the chip substrate 101. The communication photodiode 102 is the same as that of the first embodiment and includes a light absorption layer (not shown) made of a semiconductor. The chip substrate 101 transmits target light incident on the communication photodiode 102.

  In the fourth embodiment, the communication photodiode 102 is configured to receive light from the upper side (upper surface) of the element. In this case, the electrode above the element of the communication photodiode 102 may be formed in a ring shape like the electrode 224 described with reference to FIG. 2, and light may be incident on the central portion. In addition, when the electrode of the element upper part is comprised from the material which permeate | transmits the light of the communication wavelength band to measure, the shape of an electrode is not restrict | limited to a ring shape. The alignment unit 103 is made of the above-described material that blocks light, and includes a hole 131 having a smaller hole diameter than the light receiving region of the communication photodiode 102. These configurations are the same as those in the first to third embodiments, and the same components are denoted by the same reference numerals.

  The optical receiving module includes an optical component 300 in which an optical fiber (first optical waveguide) 302 corresponding to the communication photodiode 102 and an optical fiber (second optical waveguide) 303 corresponding to the alignment unit 103 are integrally formed. Is provided. Each optical fiber is fixed by a fiber block 311. The condenser lens 304 and the condenser lens 305 are fixed to the condenser lens array substrate 312. The light emitted from the optical fiber 302 is condensed by the condenser lens 304, and the light emitted from the optical fiber 303 is condensed by the condenser lens 305. In addition, the arrangement intervals of the condenser lenses, the arrangement intervals of the optical fibers, and the arrangement intervals of the communication photodiode 102 and the alignment unit 103 are the same. These configurations are the same as those in the first embodiment, and the same reference numerals are given to the same configurations.

  In addition, in the fourth embodiment, the chip substrate 101 of the light receiving component is mounted on the mounting substrate 701. For example, the chip substrate 101 is mounted (flip chip connection) on the mounting substrate 701 by bumps 401 made of AuSn solder or the like. In addition, an opening 702 is formed in the mounting substrate 701 corresponding to a region where the communication photodiode 102 and the alignment portion 103 are formed.

  The mounting substrate 701 is made of, for example, a ceramic substrate and includes wiring made of Au. The wiring is formed by patterning using a known photolithography technique and etching technique. In this way, the chip substrate 101 and the optical component 300 mounted on the mounting substrate 701 are assembled. In the fourth embodiment, the mounting substrate 701 on which the chip substrate 101 is mounted is assembled by connecting to the condenser lens array substrate 312 of the optical component 300.

  In the fourth embodiment, in the alignment, the alignment light 331 emitted from the optical fiber 303 enters the hole 131 from the surface side of the chip substrate 101, passes through the hole 131, and passes through the chip substrate 101. The mounting substrate 701 and the optical component 300 are aligned so that the light detection unit 306 can detect the maximum received light intensity. In this state, the mounting substrate 701 and the optical component 300 are connected (bonded) to form an optical receiving module.

  Also in the fourth embodiment, in the alignment described above, the positional relationship between the alignment unit 103 (hole 131) and the communication photodiode 102, and the optical fiber 303 (condensing lens 305) and optical fiber 302 (condensing light). Since the positional relationship of the lens 304) is the same, the optical axis of the light emitted from the optical fiber 302 also passes through the light receiving central portion of the corresponding communication photodiode 102, and is arranged so as to have the maximum light receiving efficiency. Is obtained. In this alignment, the communication photodiode 102 does not need to detect incident light. In other words, the communication photodiode 102 needs to be connected with wiring for connecting to an external power source. There is no.

[Embodiment 5]
Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view showing the configuration of the light receiving component according to Embodiment 5 of the present invention and the configuration of an optical receiving module using this light receiving component.

  First, the light receiving component includes a communication photodiode 102 formed on a chip substrate 101. The communication photodiode 102 is the same as that of the first embodiment and includes a light absorption layer (not shown) made of a semiconductor. In addition, the chip substrate 101 transmits light to be incident on the communication photodiode 102. These configurations are the same as those in the first embodiment.

  Further, in the fifth embodiment, a plurality of signal intensity confirmation photodiodes 802 are provided on the chip substrate 101, and a hole 831 is formed in the electrode 803 formed on the upper surface of the signal intensity confirmation photodiode 802. The alignment part is configured by. Note that the electrode 803 is made of a material that blocks light, and the hole 831 has a smaller hole diameter than the light receiving region of the communication photodiode 102.

  For example, an n-type InP layer, a non-doped InGaAs layer, and a p-type InGaAs layer are sequentially formed on a chip substrate 101 made of high resistance InP by an epitaxial growth method such as MOVPE. Next, the above-described p-type InGaAs layer, non-doped InGaAs layer, and n-type InP layer are processed into a mesa shape by a known photolithography and etching technique, and a signal composed of a p-type semiconductor layer, a light absorption layer, and an n-type semiconductor layer. The intensity confirmation photodiode 802 may be used. The electrode 803 is in ohmic contact with the p-type semiconductor layer. An electrode (not shown) that is ohmic-connected is also formed on the n-type semiconductor layer. These have the same structure as the communication photodiode 102 and may be manufactured at the same time as the communication photodiode 102.

  In the optical receiving module, an optical fiber (first optical waveguide) 302 corresponding to the communication photodiode 102 and an optical fiber (second optical waveguide) 303 corresponding to the signal intensity confirmation photodiode 802 are integrally formed. The optical component 300 is provided. The light emitted from the optical fiber 302 is condensed by the condenser lens 304, and the light emitted from the optical fiber 303 is condensed by the condenser lens 305. In addition, the arrangement intervals of the condenser lenses, the arrangement intervals of the optical fibers, and the arrangement intervals of the communication photodiode 102 and the signal intensity confirmation photodiode 802 are the same.

  In the fifth embodiment, in the alignment, the alignment light 331 emitted from the optical fiber 303 is incident from the back side of the chip substrate 101, is transmitted through the chip substrate 101, and is incident on the signal intensity confirmation photodiode 802. The chip substrate 101 and the optical component 300 are aligned so that the signal intensity confirmation photodiode 802 passes through the hole 831 and is detected by the light detection unit 306 with the maximum light reception intensity. In this state, the chip substrate 101 and the optical component 300 are connected (joined) to form an optical receiving module.

  Also in the fifth embodiment, in the above-described alignment, the positional relationship between the hole 831 and the communication photodiode 102 and the positional relationship between the optical fiber 303 (the condensing lens 305) and the optical fiber 302 (the condensing lens 304). Are in the same state, the optical axis of the light emitted from the optical fiber 302 also passes through the light receiving central portion of the corresponding communication photodiode 102, and an arrangement with the maximum light receiving efficiency is obtained. In this alignment, the communication photodiode 102 does not need to detect incident light. In other words, the communication photodiode 102 needs to be connected with wiring for connecting to an external power source. There is no.

  In the embodiment, the signal intensity confirmation photodiode 802 provided with the hole 831 can be used for alignment as well as for signal intensity confirmation of communication light as described above. For example, the signal strength confirmation photodiode 802 can be used to detect on / off of the communication strength confirmation light by propagating the communication strength confirmation light to the optical fiber 303. In addition, the signal strength confirmation photodiode 802 may be manufactured at the same time as the communication photodiode 102, and the hole 831 may be formed in the same manner as the hole 131 in Embodiment 1, and thus a process for manufacturing is performed. The number does not increase.

  Further, there is no problem even if the light receiving diameter (mesa diameter) of the signal intensity confirmation photodiode 802 is larger than the diameter of the hole 831. This is because the signal intensity confirmation of communication light does not require high-speed photoelectric conversion and does not require a reduction in junction capacitance. In the case described above, the alignment light 331 passes through the signal intensity confirmation photodiode 802 and is partially absorbed during alignment, but the intensity of the alignment light 331 can be adjusted. Must not.

  As described above, according to the present invention, alignment is performed using a plurality of alignment portions that are formed on the chip substrate and have a hole diameter smaller than the light receiving area of the communication photodiode. Therefore, alignment can be performed with high accuracy without complicating and complicating the assembly process and without increasing the cost.

  The present invention is not limited to the embodiment described above, and many modifications and combinations can be implemented by those having ordinary knowledge in the art within the technical idea of the present invention. It is obvious. For example, in the above description, the case where the two alignment units are provided is illustrated, but the present invention is not limited to this, and three or more alignment units may be provided on one chip substrate. In the above description, the optical fiber is used as the optical component. However, the present invention is not limited to this, and a planar optical waveguide (optical circuit) may be used.

  The condensing lens may be formed on the chip substrate. For example, a lens may be formed on the back surface side of the chip substrate by a known etching technique in accordance with the photodiode formation position and the hole formation position on the main surface side. For example, a Fresnel zone plate or a convex lens can be formed. With this configuration, it is not necessary to provide a lens on the optical component side.

  DESCRIPTION OF SYMBOLS 101 ... Chip substrate, 102 ... Communication photodiode, 103 ... Positioning part, 121 ... Semiconductor layer, 122 ... Light absorption layer, 123 ... Semiconductor layer, 124 ... Electrode, 131 ... Hole.

Claims (6)

A communication photodiode formed on a chip substrate having a light absorption layer made of a semiconductor and transmitting light of interest;
And a plurality of alignment portions formed on the chip substrate, each having a hole portion having a hole diameter smaller than a light receiving region of the communication photodiode. parts. The light receiving component according to claim 1,
A mounting substrate on which the chip substrate is mounted;
A light receiving component comprising: a through hole formed in the mounting substrate corresponding to the hole. In the light receiving component according to claim 1 or 2,
A signal intensity confirmation photodiode formed on the chip substrate with a light absorption layer made of a semiconductor,
An electrode formed on the upper surface of the signal intensity confirmation photodiode,
The light receiving component, wherein the hole is formed in the electrode. In the light receiving component according to claim 1 or 2,
Provided with wiring formed on the chip substrate,
The light receiving component, wherein the hole is formed in the wiring. A first step of forming a communication photodiode including a light absorption layer made of a semiconductor on a chip substrate through which light is transmitted;
A second step of forming, on the chip substrate, a plurality of alignment portions each made of a material that blocks light and having a hole portion having a hole diameter smaller than a light receiving region of the communication photodiode;
A third step of forming an optical component in which a first optical waveguide corresponding to the communication photodiode and a second optical waveguide corresponding to the alignment portion are integrally formed;
A fourth step of disposing a light detection means on the light emission side of the optical component with the chip substrate interposed therebetween;
The optical component and the chip substrate are aligned in a state where alignment light emitted from the second optical waveguide passes through the hole and is detected by the light detection means, and the optical component is placed on the chip substrate. And a fifth step of combining to form an optical receiver module. A method for manufacturing an optical receiver module, comprising: In the manufacturing method of the optical receiving module according to claim 5,
A sixth step of mounting the chip substrate on a mounting substrate;
In the fifth step, the optical component is mounted on the mounting substrate, and the optical component is combined with the chip substrate.

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