JP2001119090A - Method for manufacturing semiconductor light emitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent output reduction due to a contamination substance within a package to obtain a stable light output and surely enhance in a semiconductor laser device, which is airtightly sealed in the package. SOLUTION: Surfaces of a semiconductor laser element 10, a waveguide-type light wavelength conversion element 15, collimator lenses 12, 21, a focusing lens 13, and a based-pass filter 4 are processed with a compound of water repellent and oil repellent properties, and they are disposed within a package to be sealed airtightly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor light emitting device, and more particularly to a method of manufacturing a semiconductor light emitting device in which a semiconductor light emitting element and an optical member are fixed and sealed in a package with an adhesive containing an organic substance. It is.

[0002]

2. Description of the Related Art Conventionally, light emitted from a semiconductor laser device or a single-mode semiconductor laser device as a light source of a printing device, an image processing device, or the like is incident on an inverted domain LiNbO ₃ waveguide type wavelength conversion device. There is known a waveguide type wavelength converter that obtains light having a half wavelength. Such semiconductor light emitting devices are usually controlled in temperature by a Peltier element or the like in order to stabilize the light output and the oscillation wavelength. In order to prevent this, it is common to seal in a metal case or the like with dry air or dry nitrogen.

In this case, for example, in the case of a waveguide type wavelength converter, a semiconductor laser element, a header for bonding the semiconductor laser element, a Peltier element, and a high thermal conductivity used between the header and the Peltier element are provided. A reference plate, an optical lens, an optical mirror, and a wavelength conversion element are incorporated. Furthermore, a metal lid with a window for extracting light is attached to this case by parallel seam welding.

However, when bonding the semiconductor laser element to the header, an alloy solder such as gold tin, tin lead, or indium tin, or a solder such as tin or indium is used. At the time of this soldering, a material containing an organic substance such as a flux may be used in order to avoid a decrease in the wettability of the solder on a surface to be fixed due to oxidation or the like of the solder surface. This flux is later washed and removed with an organic solvent or the like, but there is a problem that it is very difficult to remove the flux when the surface area inside the package is large or when the flux enters fine gaps in the optical element.

[0005] Further, the solder bonding method is also used between the header and the heat conductive reference plate, and the flux is usually used several times, so that the possibility of contamination in the package increases.

[0006] When a thermistor for temperature control is attached to the header, a thermally conductive adhesive such as silicone is used. These adhesives also contain organic substances such as siloxane or softener. Therefore, the inside of the package may be contaminated by these organic substances.

Further, for bonding the Peltier device to the package or bonding the Peltier device to the heat conductive reference plate,
For example, a silver paste or the like may be used, and the filler contained in the silver paste is later removed by appropriate gas baking at 100 to 150 ° C., but may remain adsorbed inside without being completely degassed. Also, when an adhesive is used for fixing an optical lens or an optical mirror, organic substances may remain and the inside of the apparatus may be contaminated.

On the other hand, the surface of a semiconductor laser element or an optical member is usually coated with one or more dielectric films in order to control the reflectance. It is known that surfaces coated with these glass members and dielectrics adsorb polar molecules such as water. This is because the force acting to reduce the surface energy acting between water molecules is smaller than the force acting between water and the glass surface, so that the wettability is improved. By this function, the optical member and the semiconductor laser element surface inside the sealed package are
It is considered that contaminants such as polar siloxane are easily adsorbed.

As described above, the source of contamination in the apparatus is based on a so-called bonding process, which is necessarily performed to secure members, establish electrical continuity, and ensure heat conduction when assembling parts. In some cases, it is attached not only to the object but also to the member to be used and brought into the package. When the package is sealed in dry nitrogen or dry air in such a state, these contaminants are deposited on the surface of the optical member, interrupt the optical path, and cause a problem such as a decrease in light amount. This phenomenon tends to occur particularly in a portion where the light density of the light intensity is high.

However, when the distance between the semiconductor laser element and the wavelength conversion element is close to each other by several μm or less as in a waveguide type wavelength conversion apparatus, no contamination occurs on the output end face side of the semiconductor laser element. Rather, it has been found that contaminants are generated at the output end of the wavelength conversion element at an accelerated rate.
In particular, when the apparatus was continuously operated at a constant current and the change in light intensity with time was observed, it was found that the degree of decrease in light intensity was gradually accelerated with the passage of time. This is presumably because, when any foreign matter adheres to the light emitting end face, the foreign matter itself absorbs light, and the foreign matter itself increases the deposition rate.

For this reason, contaminants in the semiconductor laser device have been a very serious problem in ensuring the reliability over time of the laser device. This is because the wavelength of light is shortened, that is, the energy of light per photon is increased, and even at a lower power density, for example, about 1 mW, foreign matter is deposited.

Therefore, a laser optical crystal such as YAG or YVO ₄ is excited by using a semiconductor laser element as an excitation light source,
Even in the case of a wavelength conversion device configured to obtain infrared light and to enter the wavelength of the infrared light into a wavelength conversion element such as KTP to obtain a half wavelength, the wavelength becomes short, so that foreign matter on the light emission surface is reduced. May increase the deposition rate. As described above, even in the intracavity type second harmonic generation device, contamination by foreign matter on the surface of the optical member on the optical path when sealing is a serious problem in securing reliability.

Further, when a semiconductor laser device that does not perform wavelength conversion is sealed in a package as described above,
When there was contamination due to flux in the package or contamination due to a heat conductive adhesive such as silicone, a sharp decrease in light output was observed. In particular, Si on the surface of the optical member
Analysis revealed that O ₂ had been deposited. This is presumably because silicone contaminants were siloxane-bonded to the glass surface and changed to SiO ₂ by infrared light or visible light.

[0014]

As described above, in the conventional semiconductor light emitting device, when the device is sealed in a package, flux or conductive paste or the like during mounting is applied to the end face of the light emitting portion or the light transmitting portion of the optical member. There has been a problem that a residue of an organic substance such as an adhesive is deposited as a foreign substance, or the moisture in the package adheres, and the light output gradually decreases, and finally stops. Particularly, in a semiconductor laser device having a short oscillation wavelength and a high output, there is a problem that a deposition rate of a contaminant is high.

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention is intended to provide a highly reliable semiconductor laser device having a stable optical output by preventing organic substances and moisture remaining in a sealed semiconductor laser device from lowering the optical output. It is intended to provide a manufacturing method.

[0016]

A method of manufacturing a semiconductor light emitting device according to the present invention is directed to a method of manufacturing a semiconductor light emitting device for sealing a semiconductor light emitting element and an optical member in a package.
The surface of the semiconductor light emitting element and the optical member is treated with a water / oil repellent compound.

The water- and oil-repellent compound is a fluoroalkyl carboxylic acid, a perfluoroalkyl carboxylate,
It is desirably at least one selected from the group consisting of perfluoroalkyltrimethylammonium salts, dimethylsilicone compounds, fluoroalkylsilane compounds, fluorine compounds, and fluorine-based silane coupling agents.

Preferably, the fluorine compound is at least one selected from the group consisting of tetrafluoroethylene, carbon fluoride, pitch fluoride and fluoroalkylate polymer.

[0019] The fluorine-based silane coupling agent is preferably the general formula is a compound represented by _{Rf a R b SiX 4-ab} ( where, Rf is a fluoroalkyl group, R represents an alkyl group, Si is silicon , X is an alkoxyl group, a halogen group or an amino group, and 1 ≦ a ≦ 3, 0 ≦ b
≦ 2. ).

[0020]

According to the method for manufacturing a semiconductor light emitting device of the present invention, the surfaces of the semiconductor light emitting element and the optical member sealed in the package are treated with a water and oil repellent compound, so that the surfaces are water repellent. Since the film of the oil-repellent compound is formed, water molecules in the air, organic substances in the package, and the like are unlikely to adhere to the light emitting surface of the semiconductor light emitting element or the optical member. Therefore, since these contaminants do not block the optical path, a decrease in optical output can be prevented, and a stable output can be obtained.

In addition, since these contaminants do not accumulate on the light emitting surface over time, long-term reliability can be improved.

[0022]

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

A description will be given of a method of manufacturing a waveguide type wavelength conversion device having an oscillation wavelength of 530 nm according to the first embodiment of the present invention.

As shown in FIG. 1, this wavelength conversion device
A semiconductor laser device 10, a collimator lens 12 for collimating a laser beam (rearward emitted light) 11R emitted from the semiconductor laser device 10 in a divergent light state, and a condensing lens for converging the parallelized laser beam 11R. 13, a narrow-band bandpass filter 14 as a wavelength conversion element disposed between these lenses 12 and 13, and a mirror 20 disposed at a converging position of the laser beam 11R by the condenser lens 13. ing.

The front end face (left end face in the figure) of the semiconductor laser element 10 is directly coupled to the end face of the waveguide type optical wavelength conversion element 15.

The light wavelength conversion element 15 is composed of, for example, 5 mol of MgO in LiNbO ₃ which is a ferroelectric substance having a nonlinear optical effect.
A periodic domain in which a domain inversion portion 17 in which the direction of spontaneous polarization parallel to the Z-axis is inverted is periodically formed on a substrate 16 made of a% -doped crystal (hereinafter referred to as MgO-LN). A channel optical waveguide 18 extending along the inverted structure is formed.

The periodic domain inversion structure is formed such that the domain inversion portions 17 are arranged in the X-axis direction of the substrate 16. Such a periodic domain inversion structure can be formed by, for example, a method disclosed in JP-A-6-242478.

On the other hand, in the channel optical waveguide 18, after forming the periodic domain inversion portion 17, a metal mask pattern is formed on the + Z plane of the substrate 16 by known photolithography and lift-off, and the substrate 16 is placed in pyrophosphoric acid. It can be produced by a method such as an annealing treatment after the mask is removed by immersion and proton exchange treatment. afterwards,
Edge polishing is performed on both end surfaces 18a and 18b of the channel optical waveguide 18, and an AR (non-reflection) coating 30 for the laser beam 11 as a fundamental wave is applied to the end surface of the element including the end surface 18a.
A with respect to a second harmonic 19 to be described later
When the R coat 31 is applied, the light wavelength conversion element 15 is completed. Both end faces (cleavage faces) of the semiconductor laser 10 are coated with an LR (low reflectivity) coat 32 for light having the oscillation wavelength.

In the waveguide-type wavelength converter constructed as described above, the semiconductor laser element 10 and the waveguide-type optical wavelength conversion element 15 are temperature-controlled by a Peltier and a thermistor, not shown, and are maintained at a constant temperature. ing.

When the waveguide-type wavelength converter according to the present embodiment is sealed in a package, the light emitting side end face of the semiconductor laser device 10 is directly coupled to the waveguide-type wavelength converter, so that contamination in the package is prevented. The substance hardly accumulates, but the light emitting end face 18 of the waveguide type optical wavelength conversion element
Contaminants easily accumulate on the b side.

Next, the treatment with the water / oil repellent compound according to the present invention will be described.

Before placing the above members in a package,
It contains a perfluoroalkylcarboxylic acid (the number of carbon atoms in the carbon chain of the alkyl moiety is 7 to 13). By placing the solution in a water-isopropanol solution for several minutes to several tens of minutes, the surface of the dielectric film formed on the end face of the resonator becomes perfluoroalkylcarboxylic acid (the number of carbon atoms in the carbon chain of the alkyl portion is 7 to 7).
To 13) are applied.

The above-mentioned perfluoroalkylcarboxylic acid (the carbon number in the carbon chain of the alkyl portion is 7 to 1)
Instead of the treatment in a water-isopropanol solution containing 3), a treatment method in a vapor atmosphere of perfluoroalkylcarboxylic acid (the carbon number in the carbon chain of the alkyl portion is 7 to 13) may be used. .

In this embodiment, the members such as the semiconductor light emitting element, the wavelength conversion chip, the Peltier, and the thermistor are processed before the members are placed in the package. A method of putting in a steam atmosphere later may be used.

As described above, in a sense, it has been found that the formation of contaminants on the surface of the optical member from the beginning can prevent the accumulation of contaminants generated inside the sealed package.

By using this processing method, deposition of SiO ₂ or the like on the optical path does not occur even after the package sealing step, and deterioration over time such as a decrease in optical output hardly occurs.

In the above embodiments, the waveguide type wavelength converter has been described. However, the present invention does not perform wavelength conversion on light emitted from a wavelength converter using a laser crystal such as YAG or a semiconductor laser device. The present invention can be applied to the semiconductor laser device to be used, and the same effect as in the above embodiment can be obtained.

Next, a description will be given of a method of manufacturing a waveguide type wavelength conversion device having an oscillation wavelength of 530 nm according to a second embodiment of the present invention.

The structure of this wavelength conversion element is the same as that of the wavelength conversion element according to the first embodiment, and is as shown in FIG. However, the processing method using the water- and oil-repellent compound is different from that of the first embodiment, and only this processing method will be described.

Before arranging the members constituting the wavelength conversion element in a package, a water-isopropanol solution containing a fluoroalkylcarboxylic acid (the number of carbon atoms in the carbon chain of the alkyl portion is 2 to 10) is contained for several minutes. By placing it for several tens of minutes, fluoroalkylcarboxylic acid (the number of carbon atoms in the carbon chain of the alkyl portion is 2 to 10) is adhered to the surface of the dielectric film formed on the end face of the resonator.

[0041] By using this processing method, even after a package sealing process, deposition of SiO ₂ or the like of the optical path is no longer occurs, deterioration over time, such as reduction in light output is less likely to occur.

Next, a method of manufacturing a waveguide type wavelength conversion device having an oscillation wavelength of 530 nm according to a third embodiment of the present invention will be described.

The configuration of this wavelength conversion element is the same as that of the wavelength conversion element according to the first embodiment, and is as shown in FIG. However, the processing method using the water- and oil-repellent compound is different from that of the first embodiment, and only this processing method will be described.

Before disposing the members constituting the wavelength conversion element in a package, the perfluoroalkyltrimethylammonium salt (the carbon number in the carbon chain of the alkyl portion is 6
To 13) in a water-isopropanol solution containing several minutes to several tens of minutes to form a perfluoroalkyltrimethylammonium salt (the number of carbon atoms in the carbon chain of the alkyl portion on the surface of the dielectric film formed on the resonator end face). Apply 6 to 13).

[0045] By using this processing method, even after a package sealing process, deposition of SiO ₂ or the like in the optical path is no longer occurs, deterioration over time, such as reduction in light output is less likely to occur.

Next, a description will be given of a method of manufacturing a waveguide type wavelength conversion element having an oscillation wavelength of 530 nm according to a fourth embodiment of the present invention.

The configuration of this wavelength conversion element is the same as that of the wavelength conversion element according to the first embodiment, and is as shown in FIG. However, since the treatment method using the water- and oil-repellent compound is different from that of the first embodiment, only this treatment method will be described.

Before disposing the member in the package, the member is placed in a vapor atmosphere of a fluorine-based silane coupling agent for several minutes to several tens of minutes so that the surface of the dielectric film formed on the resonator surface has a fluorine-based silane coupling agent. To adhere. The durability of this fluorine silane coupling agent is
It is very low only by adsorbing by der waals force,
It is important to form siloxane bonds with the glass surface. Further, since the adhesion density of the fluorine-based silane coupling agent also affects the effect, the adhesion conditions are optimized by X-ray electron spectroscopy.

In this embodiment, the members such as the semiconductor light emitting element, the wavelength conversion chip, the Peltier, and the thermistor are processed before the members are installed in the package. However, these members are completely installed in the package. A method of putting in a steam atmosphere later may be used.

As described above, it has been found that, in a sense, the formation of contaminants on the surface of the optical member from the beginning can prevent the accumulation of contaminants generated inside the sealed package.

By using the present processing method, deposition of SiO ₂ or the like on the optical path does not occur even after the package sealing step, and deterioration with time such as a decrease in optical output hardly occurs.

[0052] In particular, the general formula, Rf _a R _b SiX
_4-ab (where Rf is a fluoroalkyl group, R is an alkyl group, Si is silicon, X is an alkoxyl group, a halogen group or an amino group, and 1 ≦ a ≦ 3 and 0 ≦ b ≦ 2). When the represented fluorine-based silane coupling agent is used, deterioration over time, such as a decrease in optical output, is more unlikely to occur.

Next, a description will be given of a method of manufacturing a waveguide type wavelength conversion element having an oscillation wavelength of 530 nm according to a fifth embodiment of the present invention. The configuration of this wavelength conversion element is the same as that of the wavelength conversion element according to the first embodiment, and FIG.
The configuration is as shown in FIG. However, the first embodiment differs from the first embodiment in that the treatment is performed using a dimethyl silicone compound, a fluoroalkylsilane compound, tetrafluoroethylene, fluorocarbon, or pitch fluoride as a water- and oil-repellent compound. Are different.

By using this treatment method, deposition of SiO ₂ or the like on the optical path does not occur even after the package sealing step, and deterioration over time such as a decrease in optical output hardly occurs.

[Brief description of the drawings]

FIG. 1 is a diagram showing a waveguide type wavelength conversion device according to a first embodiment of the present invention.

[Explanation of symbols]

 10 Semiconductor laser element 12,21 Collimator lens 13 Condensing lens 14 Bandpass filter 15 Waveguide type optical wavelength conversion element 16 Substrate 17 Domain inversion section 18 Optical waveguide 20 Mirror

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01L 21/312 H01L 21/312 C

Claims (4)

[Claims] 1. A method of manufacturing a semiconductor light emitting device in which a semiconductor light emitting element and an optical member are sealed in a package, wherein the surfaces of the semiconductor light emitting element and the optical member are treated with a water / oil repellent compound. Of manufacturing a semiconductor light emitting device. 2. The water- and oil-repellent compound is a fluoroalkyl carboxylic acid, a perfluoroalkyl carboxylate, a perfluoroalkyl trimethyl ammonium salt,
2. The method according to claim 1, wherein the method is at least one selected from the group consisting of a dimethyl silicone-based compound, a fluoroalkylsilane compound, a fluorine compound, and a fluorine-based silane coupling agent. 3. The semiconductor light emitting device according to claim 2, wherein the fluorine compound is one or more selected from the group consisting of tetrafluoroethylene, carbon fluoride, pitch fluoride, and fluoroalkylate polymer. Manufacturing method. 4. The method according to claim 1, wherein the fluorine-based silane coupling agent is
The method of manufacturing a semiconductor light emitting device according to claim 2, wherein the general formula is a compound represented by _{Rf a R b SiX 4-ab} . (However, Rf is a fluoroalkyl group, R is an alkyl group, Si is silicon, X is an alkoxyl group, a halogen group or an amino group, and 1 ≦ a ≦ 3 and 0 ≦ b ≦ 2.)