JP3197758B2 - Optical coupling device and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser and an optical waveguide made of fluorinated polyimide, which are integrated on the same substrate. The present invention relates to an optical coupling device having a structure in which light emitted from the outside through a wave path or external light incident on an optical waveguide is detected by a photodiode.

[0002]

2. Description of the Related Art Conventionally, integrated formation of a semiconductor optical device such as a semiconductor laser and an optical coupling device comprising an optical waveguide is performed by, for example,
Proceedings of the Spring Society of Applied Physics 29p-ZH-1, (1988
Year), pp. 846 (Yoshio Suzuki et al .: "Semiconductor light source, fabrication of glass waveguide integrated optical device"). This is because, as shown in FIGS. 13A and 13B, a core layer 9 such as an SiO ₂ film (which is a clad layer because of its low refractive index) is used as the upper clad layer 15 by sputtering or the like.
(Since it has a relatively high refractive index, it is used as a core layer)
However, in this method, since the core inclined portion 10 in which the center line of the beam and the core layer are inclined is formed (FIG. 13A), light is scattered, and Since the refractive index difference Δn of the cladding layer cannot be controlled to be small, the core layer 9
Cannot be thickened, and is at most about 1 μm. Even if the end face of the core layer 9 is etched so that the end face of the optical waveguide has a gap of several μm to tens of μm with the emission end face of the semiconductor laser [FIG. 13 (b)], it is extremely difficult to align the height of the active layer 7 of the semiconductor laser with the height of the core layer 9 of the optical waveguide, and not only the connection efficiency is poor but also the semiconductor optical device and the optical waveguide When a gap such as air is generated therebetween, dust and
In addition to the adhesion of water droplets and the like, when the core inclined portion 10 is removed, if the core inclined portion 10 is removed, for example, by ion etching or the like, there is a problem that the semiconductor optical device is damaged due to ion bombardment and the characteristics of the semiconductor optical device deteriorate. . on the other hand,
When the optical waveguide is made of an organic substance such as PMMA [poly (methyl methacrylate)] used for a resist or the like, the refractive index difference Δn can be reduced, and therefore, there is an advantage that the core layer 9 can be thickened. There is a merit that the position of the active layer 7 of the laser and the core layer 9 can be easily aligned and the optical connection efficiency is improved. However, the heat resistant temperature of the above-mentioned organic substances such as PMMA is 230 at most.
℃, and the back surface polishing removal 17 for thinning the semiconductor laser substrate performed in the final stage of the fabrication of the semiconductor laser.
(See FIG. 10), and the back ohmic electrode 18 (FIG. 1).
0), it is necessary to perform a heat treatment at about 400 ° C., and it is extremely difficult to integrally form the semiconductor laser with the semiconductor laser due to problems such as heat resistance. So,
Conventionally, a semiconductor optical device was manufactured by forming a backside ohmic electrode 18 and polishing the backside once for thinning a semiconductor laser substrate, and then bonding the thinned substrate to another substrate. Since the optical waveguide must be manufactured in this state, the integrated formation of the semiconductor optical device and the optical waveguide complicates the manufacturing process and has a practical problem. Also, when etching this kind of organic substance, a metal such as Ti is used as a mask, so that after the etching of the core layer and the etching of the optical waveguide in the final stage, the removal of the remaining metal mask such as Ti is performed. At this time, the semiconductor substrate is removed by dissolving with an acidic solution such as hydrochloric acid that dissolves the semiconductor substrate, or is removed by dry etching with a CF (carbon-fluorine) -based reactive gas.
There is a problem that the polyimide optical waveguide and the semiconductor laser substrate are damaged, and there has been no optical waveguide that can be integrally formed with the semiconductor optical element.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art.
The optical connection efficiency between the semiconductor optical device and the optical waveguide is good, the semiconductor optical device and the optical waveguide are integrated on the same substrate by constructing a new optical waveguide with good heat resistance and less damage and deterioration of the semiconductor optical device. An object of the present invention is to provide an optical coupling device having a structure that can be manufactured at a high performance and having excellent durability and a method of manufacturing the same. The present invention specifically solves the following problems. (1) It is possible to reduce the refractive index difference Δn between the core layer and the cladding layer and increase the thickness of the core layer so that the center lines of the active layer of the semiconductor laser and the core layer of the optical waveguide are at the same height. The optical connection efficiency is improved by making it easy to realize, and by configuring the end surface of the core layer to be perpendicular to the substrate (parallel to the end surface of the semiconductor optical device). (2) Maximum temperature 40 in the fabrication process of the semiconductor optical device
An optical waveguide having heat resistance that can withstand 0 ° C. is realized. (3) The protection of the end face of the semiconductor optical device and the installation of the electrode pads are simultaneously realized. (4) Select a mask such that removal of the mask remaining after etching the fluorinated polyimide optical waveguide does not damage or deteriorate the optical waveguide and the semiconductor optical device.

[0004]

In order to solve the above-mentioned problems of the present invention, an optical coupling device and a method of manufacturing the same according to the present invention are configured as described in the appended claims. That is, a three-layer structure in which a semiconductor laser substrate and a lower clad layer, a core layer, and an upper clad layer made of fluorinated polyimides having different fluorine contents are laminated on the semiconductor laser substrate as described in claim 1. An optical coupling device in which the optical waveguides are integrally configured,
The emission end face of the semiconductor laser is coated with a high fluorine content fluorinated polyimide having the same composition as the lower cladding layer made of the above fluorinated polyimide, and an end face of a core layer made of a low fluorine content fluorinated polyimide, and a semiconductor. A gap is provided between the laser light emitting end face , and the center line of the active layer of the semiconductor laser substrate is substantially at the same height as the center line of the core layer, and the fluorine content is higher than that of the core layer. The gap is filled with polyimide, and an upper clad layer is formed on the core layer. According to a second aspect of the present invention, a photodiode
A fluorine-containing substrate on a photodiode substrate and the photodiode substrate.
The lower part made of fluorinated polyimide
Lad layer, core layer and upper clad layer
An optical coupling device in which an optical waveguide having a structure is integrally formed,
Connect the light-receiving end face of the photodiode to the fluorinated polyimide
Of the same composition as the lower cladding layer consisting of
Coated with high fluorinated polyimide, low fluorine content
End face of the core layer made of fluorinated polyimide
Provide a gap between the light-receiving end face of the diode and the
The center line of the active layer of the photodiode substrate is the center line of the core layer.
Approximately the same height as above, containing fluorine more than the above core layer
Fill the above gap with a large amount of fluorinated polyimide
And an upper clad layer formed on the core layer.
It is to be made. And as described in claim 3 , in claim 1 or claim 2, the fluorinated polyimide is 6FDA [2,2-Bis (3,4-dic) which is an acid dianhydride.
arboxyphenyl) hexafluoropropane Dianhydride… 2,2-
Bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride] and PMDA [Pyromel
litic Dianhydride: pyromellitic anhydride] and fluorinated diamine TFDB [2,2-Bis (t
[Rifluoromethyl) -4,4'-diaminobiphenyl ... 2,2-bis (trifluoromethyl) -4,4'-diaminobiphenyl]]. Further, the present invention is defined by the claims.
As described in 4, wherein a method of manufacturing an optical coupling device according to claim 1, the electrode film provided on the electrode <br/> pad of the current supply region of the semiconductor laser, the resistance to oxygen plasma A step of forming using gold or platinum, or an alloy containing gold or platinum as a main component, and a lower cladding layer, a core layer, and an upper layer made of fluorinated polyimide constituting an optical waveguide on an electrode pad of a semiconductor laser ; After laminating the three layers of the cladding layer, three layers of the fluorinated polyimide,
Using a silicone-based photosensitive resist as a mask, a step of etching with oxygen plasma, and after forming the upper cladding layer, performing etching for forming an optical waveguide by oxygen plasma, and at the same time, gold, platinum, Or, up to the surface of the electrode film made of these alloys, etching the three layers of fluorinated polyimide laminated, and opening the window of the electrode portion to an electrode pad, at least including a method of manufacturing an optical coupling device and Is what you do. Further, the present invention provides a
A method for manufacturing an optical coupling device according to claim 2, wherein
On the electrode pad in the current extraction area of the photodiode.
The electrode film to be used is made of gold or white
Using gold or an alloy containing gold or platinum as a main component
Forming process and over the photodiode electrode pad
In addition, below the fluorinated polyimide constituting the optical waveguide
Three layers, the inner cladding layer, core layer, and upper cladding layer.
After the layering, the three layers of the fluorinated polyimide are
Using cone-based photosensitive resist as a mask, oxygen
The process of etching by plasma and the upper cladding
After the layer is formed, an optical waveguide is formed by oxygen plasma
At the same time as etching for
Until the surface of the electrode film made of platinum or their alloy
Etch three layers of fluorinated polyimide
To open the window of the electrode part and use it as an electrode pad.
A method of manufacturing an optical coupling device including at least
It is. In addition, the present invention provides
6. The method for manufacturing an optical coupling device according to claim 4 or claim 5.
The lower part made of fluorinated polyimide constituting the optical waveguide
Three layers, the inner cladding layer, core layer, and upper cladding layer.
In the layering step, the acid dianhydride and the fluorinated diamine
Fluorinated polyimide produced by polymerization and dehydration reactions
This is a method for manufacturing a stacked optical coupling device. Then, the silicone-based photosensitive resist (SPP)
... silicone-basedpositive pyr) is acetylated [poly (phenylsilsesquioxane) ... po
ly (phenylsilsesquioxane)] and diazonaphthoquinone as a photosensitive agent. In the optical coupling device and the method of manufacturing the same according to the present invention, specific points different from the prior art are as follows. Is to be coated. (2) As a material for the optical waveguide, a fluorinated polyimide having high heat resistance and capable of controlling the refractive index difference Δn between the core layer and the cladding layer to be small is used, and at the same time, Au, Pt, or the like is formed on the uppermost electrode film of the electrode pad. Alternatively, an alloy containing these metals as main components is used. (3) A structure in which after forming the cladding layer and the core layer, a gap is provided between the core layer and the end face of the semiconductor laser, the core is etched, and the gap is filled with fluorinated polyimide of the same material as the lower cladding layer. And (4) In order to form the end face of the core layer in the fluorinated polyimide optical waveguide and to form a three-layer structure, the electrode pad covered with the fluorinated polyimide layer is opened by oxygen plasma using the SPP resist as a mask to open a window. By etching, an optical coupling device integrally formed on the same substrate is manufactured.

[0005]

According to the optical coupling device of the present invention, an optical waveguide integrally formed on the same substrate as a semiconductor laser substrate is made of fluorinated polyimide having high heat resistance. The semiconductor optical device does not deteriorate even at the maximum heating temperature of 400 ° C. in the semiconductor optical device manufacturing process, and has sufficient durability in the semiconductor optical device manufacturing process. Can be easily realized. In addition, since the end face of the semiconductor optical device is covered with fluorinated polyimide having high corrosion resistance as well as high heat resistance, water droplets, dust, etc. do not adhere to the end face and cause a change in the reflectance of the semiconductor laser. Stable light output characteristics of the semiconductor laser and dark current characteristics of the photodiode can be obtained. Further, the refractive index difference Δ between the core layer and the cladding layer
Since n can be reduced, the core layer can be thickened, the alignment between the active layer of the semiconductor laser and the core layer is facilitated, and the etched mirror of the core layer is formed on the etched mirror surface side of the semiconductor optical device. Therefore, it can be manufactured with low light scattering and high optical connection efficiency with good reproducibility. In the method of manufacturing an optical coupling device according to the present invention, the mask remaining after etching the optical waveguide does not damage the semiconductor laser substrate and the optical waveguide, and the mask is easily removed. Therefore, good transmission characteristics of the optical waveguide can be obtained.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in more detail with reference to the drawings. FIGS. 1A and 1B are schematic diagrams illustrating a configuration of an optical coupling device exemplified in an embodiment of the present invention. In this embodiment, a case where a semiconductor laser is used as a semiconductor optical device will be described. In order to realize the optical coupling device of the present invention, 6FDA which is an acid dianhydride and PM
A mixture of two types of DA and fluorinated diamine TFDB was prepared. That is, acid dianhydride / fluorinated diamine: 6FDA / TFDB (refractive index is wavelength λ: 0.84 μm
1.59) and acid dianhydride / fluorinated diamine: PMDA / TFDB (refractive index is wavelength λ: 0.84 μm)
two kinds of fluorinated polyimides having different mixing ratios of 1.53 with respect to m (the refractive index of both is 1.533 and 1.541 with respect to the wavelength λ0.84 μm, the refractive index difference Δn: 0.00)
8) A polymer was prepared in advance. First, FIG.
As shown in (b), a large number of semiconductor laser units 2 having three quantum well structure active layers are formed on a semiconductor laser substrate (GaAs substrate) 1 having a thickness of about 350 μm. The dimension corresponding to one chip of the one semiconductor laser is about 0.8 × 1.0 mm. Here, the electrodes will be described. FIG. 2A is a cross-sectional view taken along a line AA in FIG.
FIG. 11B shows a cross section taken along line BB of FIG.
Are displayed in the same manner. As shown in FIGS. 2A and 2B, AuZnNi is used in the current injection region 3 of the semiconductor laser.
Ohmic contact is formed, and other parts are Si
An insulating film such as O ₂ or Si ₃ N _{4 is} coated from the semiconductor laser portion 2 to the electrode pad portion 4 and a thin film of Cr or the like is formed thereon to improve the adhesion of the electrodes. Film 5 made of Pt or Pt or an alloy containing these metals as main components is formed. In this case, the depth of the etched mirror 6 of the semiconductor laser unit 2 is 5.5 μm below the active layer 7.
Then, a total of 8 μm in thickness of 2.5 μm was etched using a reactive gas of pure chlorine. Next, in order to form the lower cladding layer 8 of the optical waveguide, a fluorinated polyimide having a refractive index of 1.533 is applied, followed by baking to cause a dehydration reaction. The entire part 4 was covered (FIGS. 3A and 3B).
The thickness of the fluorinated polyimide except for the vicinity of the end face of the semiconductor laser was 3.9 μm for the target value of 4 μm.
Was thick. In order to continuously form the core layer 9,
A 1.541 fluorinated polyimide having a different refractive index from the cladding layer was applied and sintered [FIGS. 4 (a) and 4 (b)]. In this case, since the refractive index difference Δn can be controlled as small as 0.008, the thickness of the core layer 9 for obtaining a single mode is 3.5 μm. Therefore, the target thickness of the core layer 9 at this time is set to 3 μm. . In practice, a thickness of 3.0 μm could be formed almost as desired. Thereafter, FIGS. 5A and 5B
As shown in FIG. ₂ , SP, which is a silicone-based positive photosensitive resist in which a portion exposed to oxygen plasma on a propagation path for guiding light is changed into a SiO ₂ altered layer 12.
After performing photolithography using P resist 11,
The core inclined part 10 formed near the end face of the semiconductor laser in an oxygen gas atmosphere was removed by reactive etching. In this embodiment, the core layer 9 formed on the electrode pad portion 4 was not etched. The etching depth at this time was slightly oversized and was about 4 μm. Core layer 9
A gap (gap) 13 of 10 μm was formed between the end face of the semiconductor laser and the end face of the semiconductor laser. In this reactive etching, the lower cladding layer 8 is left on the semiconductor laser. Therefore, even if the core layer 9 is over-etched as in the present embodiment, the semiconductor laser end face is covered with the fluorinated polyimide, so that the semiconductor laser end face is not subjected to ion bombardment during etching. As a result, the characteristics of the semiconductor laser are not degraded. When a current is finally injected after the formation of the back electrode, the center of the core layer is 5.4 μm from the bottom surface of the etching, and the deviation from the height of the active layer 7 to 5.5 μm is only about 0.1 μm. Since the core layer is as thick as 3 μm, the beam emitted from the active layer 7 of the semiconductor laser is sufficiently transmitted into the core layer 9. Surface of the SPP resist 11 left on the core layer 9, since the SiO ₂ affected layer 12 is exposed to an oxygen plasma changed to SiO ₂ is formed, was immersed a few seconds to 10% of the buffered hydrofluoric acid, When removed using Solfine ™ and rinsed with ethyl alcohol, the fluorinated polyimide layer is not damaged and S
Only the PP resist 11 was completely removed [FIG.
(A) (b)]. Thereafter, a cladding material made of fluorinated polyimide is again applied and sintered in the same procedure as the formation of the lower cladding layer 8 to form the upper cladding layer 15 and at the same time, between the semiconductor laser and the core layer 9. A certain gap 13 was also filled (FIGS. 7A and 7B). Further, since the viscosity of the fluorinated polyimide is high, it is also effective for flattening. After coating and baking, the step in the gap 13 near the end face of the semiconductor laser is greatly reduced. In order to convert the fluorinated polyimide having the three-layer structure into an optical waveguide whose optical axis matches that of the semiconductor laser unit 2 previously manufactured, a photolithography technique using an SPP resist 11 and a reactive ion etching process using oxygen plasma At the same time as forming the optical waveguide 16, the fluorinated polyimide layer on the electrode pad portion 4 was opened to expose the electrode film (Au) 5 [FIG.
(A), (b)]. FIG. 9 is a plan view showing one chip of the semiconductor laser substrate, and shows the position of the optical waveguide (three-layer structure) 16. Further, in order to form a backside electrode of the semiconductor laser, the backside polishing removal 17 for thinning the semiconductor laser substrate is performed by about 280 μm, the thinning is performed to about 70 μm, and AuGe is formed to form the backside ohmic electrode 18.
Ni alloy is deposited by resistance heating and is baked at 400
The resultant was baked at about 20 ° C. for about 20 seconds to obtain an optical coupling device in which the semiconductor laser of the present invention and the optical waveguide shown in FIGS. 10A and 10B were formed on the same substrate. As shown in FIGS. 10A and 10B, the optical coupling device of the present invention uses a light guide (three-layer structure) made of fluorinated polyimide having good heat resistance and corrosion resistance to form a semiconductor laser or a photodiode. In this case, dust and water droplets do not adhere to the end face of the device, and the environmental conditions in which the device can be used are reduced. Also, by using fluorinated polyimide, the refractive index difference Δn between the core layer and the cladding layer can be reduced, so that the core layer 9 can be made thicker and the height of the active layer 7 of the semiconductor laser can be easily adjusted. In addition, since the end face of the core layer 9 can be removed by etching in parallel with the end face of the semiconductor optical element, scattered light is small when emitted from the semiconductor optical element or incident on the semiconductor optical element,
Optical connection efficiency can be greatly improved. Next, as shown in FIG. 11, a measurement probe 2 was attached to an electrode pad 4 having a window opened, in order to confirm whether or not the semiconductor laser characteristics were degraded due to the fabrication of a waveguide made of fluorinated polyimide.
4 and the current was injected into the semiconductor laser section 2 to cause the semiconductor laser to emit light. FIG. 12 shows the relationship between the injection current I (mA) and the output light L (mW). Since the end face of the semiconductor laser is not air and a polyimide waveguide having a refractive index of about 1.5 is in contact with the semiconductor laser and the reflectivity of the semiconductor laser resonance face (end face) is reduced, the threshold current for oscillation slightly decreases. However, no decrease such as the oscillation output gradient was observed. Further, as can be seen from the above IL characteristics, excellent results were obtained with an optical connection efficiency of 1 dB or less. As described above, in the present embodiment, a semiconductor laser is described as a semiconductor optical element. However, the same applies to a photodiode. In the case of this photodiode, light is transmitted through a fluorinated polyimide waveguide, and A current corresponding to the amount of light incident on the photodiode can be drawn from the upper ohmic contact region to the electrode pad portion from the active layer on the end face. Only the direction of light transmission differs between the photodiode and the semiconductor laser, and the structure is exactly the same. Although the GaAs substrate is used as the semiconductor laser substrate in the above embodiment, the same effect as that of the present embodiment can be obtained by using a substrate for a high wavelength having a smaller band gap such as an InP substrate. The present invention does not limit the type of the semiconductor laser substrate.

[0007]

As described in detail above, the optical coupling device and the method of manufacturing the same according to the present invention have the following effects. (1) Because the fluorinated polyimide covers the surface other than the electrode pads, including the end face of the semiconductor optical device (semiconductor laser or photodiode), no dust or water droplets adhere to the end face, and the usable environmental conditions are limited. Be relaxed. (2) By using a fluorinated polyimide, the refractive index difference Δn between the core layer and the cladding layer can be reduced, so that the core layer can be made thicker, and the height of the active layer of the semiconductor laser can be easily adjusted. Moreover, since the core end face is etched away in parallel with the semiconductor optical element end face, scattered light at the time of emission from the semiconductor optical element or incidence on the semiconductor optical element is small, and the optical connection efficiency can be greatly improved. Also,
Adhesion of dust and water droplets from the end face can be prevented, and the durability and reliability of the optical coupling device are improved. (3) By using an SPP resist and etching only with oxygen plasma, Au, Pt, or an alloy film thereof serves as a stopper in opening a window of an electrode pad, so that opening of the window becomes extremely easy. Further, since the SPP mask remaining after etching the optical waveguide can be easily removed without damaging the optical waveguide, an integrated configuration with an optical element such as a semiconductor laser can be realized. That is, since the etching by oxygen plasma using the SPP mask and the heat resistance of the fluorinated polyimide are compatible with the semiconductor optical device manufacturing process, integration can be easily realized.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of an optical coupling device exemplified in an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a manufacturing process of the optical coupling device exemplified in the embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a manufacturing process of the optical coupling device exemplified in the embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a manufacturing process of the optical coupling device exemplified in the embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a manufacturing process of the optical coupling device exemplified in the embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a manufacturing process of the optical coupling device exemplified in the embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a manufacturing process of the optical coupling device exemplified in the embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a manufacturing process of the optical coupling device exemplified in the embodiment of the present invention.

FIG. 9 is a plan view showing the configuration of the optical coupling device exemplified in the embodiment of the present invention.

FIG. 10 is a sectional view showing the configuration of the optical coupling device exemplified in the embodiment of the present invention.

FIG. 11 is a cross-sectional view illustrating a configuration of an optical coupling device exemplified in an embodiment of the present invention.

FIG. 12 is a graph showing characteristics of the optical coupling device exemplified in the embodiment of the present invention.

FIG. 13 is a schematic diagram showing a configuration of a conventional optical coupling device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor laser substrate (GaAs substrate) 2 ... Semiconductor laser part 3 ... Current injection area 4 ... Electrode pad part 5 ... Electrode film 6 ... Etched mirror 7 ... Active layer 8 ... Lower cladding layer 9 ... Core layer 10 ... Core inclination part 11 ... SPP resist (silicone-based photoresist) layer 12 ... SiO ₂ alteration layer 13 ... gap 14 ... beam 15 ... upper clad layer 16 ... optical waveguide (3-layer structure) 17 ... for thinning the semiconductor laser substrate 18: Backside ohmic electrode 19: Mask 20: Reactive ions 21: Portion where core inclined portion is removed (etching end surface of core layer) 22: Insulating film 23: Au (gold) electrode 24: Measurement probe

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mieko Tsubamoto 1-3-1 Gotenyama, Musashino City, Tokyo NTT Advanced Technology Co., Ltd. (56) References JP-A-4-328504 ( JP, A) JP-A-8-46292 (JP, A) JP-A-58-155788 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01S 5/00-5/50 G02B 6/12

Claims (6)

(57) [Claims] 1. A semiconductor laser substrate and an optical waveguide having a three-layer structure in which a lower clad layer, a core layer and an upper clad layer made of fluorinated polyimides having different fluorine contents are laminated on the semiconductor laser substrate. An optical coupling device, comprising: an emission end face of a semiconductor laser, coated with a fluorine-containing polyimide having a high fluorine content having the same composition as the lower cladding layer made of the fluorinated polyimide, and a fluorinated polyimide having a low fluorine content. A gap is provided between the end face of the core layer made of the semiconductor laser and the emission end face of the semiconductor laser, and the center line of the active layer of the semiconductor laser substrate is substantially at the same height as the center line of the core layer; In addition to filling the gap with a fluorinated polyimide having a higher fluorine content, an upper clad layer is formed on the core layer. Optical coupling device for. 2. A photodiode substrate, comprising : a photodiode substrate;
To over de substrate, lower cladding layer fluorine content is formed of different fluorinated polyimide, respectively, an optical waveguide of a three-layer structure of a core layer and an upper Kuratsudo layer An optical coupling device which is constructed integrally, the photodiode The light-receiving end face is coated with a fluorine-containing polyimide having a high fluorine content of the same composition as the lower cladding layer made of the fluorinated polyimide, and an end face of a core layer made of a fluorinated polyimide having a low fluorine content, A gap is provided between the photodiode and the light-receiving end face , and the center line of the active layer of the photodiode substrate is substantially at the same height as the center line of the core layer, and the fluorine content is higher than that of the core layer. An optical coupling device, wherein the gap is filled with polyimide and an upper clad layer is formed on the core layer. 3. The optical coupling system according to claim 1, wherein the fluorinated polyimide is a fluorinated polyimide formed based on a polymerization / dehydration reaction between an acid dianhydride and a fluorinated diamine. apparatus. 4. A method of manufacturing an optical coupling device according to claim 1, electrode pads of the current supply region of the semiconductor laser
An electrode film provided on a step of an alloy mainly composed of gold or platinum which is resistant to oxygen plasma, or gold, or platinum, on the electrode pads of the semiconductor laser, fluorine constituting the optical waveguide After laminating three layers of a lower clad layer, a core layer and an upper clad layer made of fluorinated polyimide, a step of etching the three layers made of the fluorinated polyimide with oxygen plasma using a silicone-based photosensitive resist as a mask, After the formation of the upper cladding layer, etching for forming an optical waveguide by oxygen plasma is performed, and at the same time, fluorinated polyimide laminated to the surface of an electrode film made of gold, platinum, or an alloy thereof of an electrode pad portion. Etching at least three layers to form a window in the electrode portion to form an electrode pad. The method of manufacturing an optical coupling device, characterized in that. 5. A method for manufacturing the optical coupling device according to claim 2.
Method for detecting the current in the current extraction region of the photodiode.
Pole electrode film provided on the pad, and forming with gold or platinum is resistant to oxygen plasma, or an alloy of gold or platinum as a main component, electrostatic photodiode
On the pole pad, a lower cladding layer made of fluorinated polyimide constituting an optical waveguide, a core layer and three layers of an upper cladding layer are laminated, and then the three layers made of the fluorinated polyimide are coated with a silicone-based photosensitive resist. Using an oxygen plasma as a mask, and after forming the upper cladding layer, performing etching for forming an optical waveguide by oxygen plasma, and simultaneously forming an electrode pad portion of gold, platinum, or an alloy thereof. A method for manufacturing an optical coupling device, comprising at least a step of etching three layers of fluorinated polyimide laminated to a surface of an electrode film to open a window of an electrode portion to form an electrode pad. 6. An optical coupling device according to claim 4 or claim 5.
In the method of manufacturing, the fluorinated poly constituting the optical waveguide
Lower cladding layer, core layer and upper cladding layer made of imide
In the step of laminating the three pad layers, the acid dianhydride and the
Fluorine generated by polymerization and dehydration of fluorinated diamine
Optical coupling device characterized by laminating polished polyimide Place
Manufacturing method.