JP2003131037A - Hologram optical element integrated with cap, hologram laser device, and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hologram optical element integrated with a cap, a hologram laser device, and a manufacturing method therefor, capable of easily forming diffraction gratings on both surfaces to reduce the manufacturing processes. SOLUTION: A plurality of diffraction gratings 4 called as a hologram formed of a pair of both surfaces are formed on both surfaces of a first substrate 1. And, a second substrate 2 is so formed as to comprise a plurality of through holes 5 corresponding to the diffraction gratings 4 of the first substrate 1. The first substrate 1 and the second substrate 2 are bonded together to provide a laminated substrate 3 which is diced into a plurality of cap-integrated HOEs8. By the above manufacturing method, the cap-integrated HOE8 in which diffraction gratings 4 are formed on both surfaces can be easily manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cap-integrated hologram optical element used for an optical pickup of an optical disk device, a hologram laser device, and a manufacturing method.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional hologram laser device 21.
It is a figure which shows the structure of.

As a hologram laser device conventionally used for an optical pickup of an optical disk device, FIG.
There is a hologram laser device 21 having a structure as shown in FIG. This will be described below as a first conventional example. First
The hologram laser device 21 in the conventional example is a semiconductor laser element (hereinafter referred to as LD) 11, a monitor submount (hereinafter referred to as MS) 12, a hologram optical element (hereinafter referred to as HOE) 13, a photodiode (hereinafter referred to as a photodiode). , PD) 14, cap 15 and stem 16
It is configured with.

The LD 11 is used as a light source in the hologram laser device 21. MS12 is LD1
1 is an optical element for monitoring the intensity of light emitted from 1. The HOE 13 is a diffraction grating having a function of splitting and refracting the light emitted from the LD 11. PD14
Is a photoelectric conversion element that receives the light emitted from the LD 11 and reflected by the information recording medium via the HOE 13 and converts it into an electric signal. The cap 15 is LD11, MS1
2 and PD 14 are sealing members that are sealed to avoid physical contact with the outside. The stem 16 has an input / output terminal and is used to mount semiconductor chips such as the LD 11, the MS 12 and the PD 14.

Next, a manufacturing process of the hologram laser device 21 of the first conventional example will be described. FIG. 3 is a diagram showing a manufacturing process of the conventional hologram laser device 21.

First, MS12, LD11 and PD14
In this order, a work called die bonding for fixing the stem 16 at a predetermined position is performed. A silver paste or the like is used to fix the MS 12, LD 11 and PD 14.
The MS 12, LD 11, and PD 14 are optically adjusted and fixed at the optimum position on the stem 16.

A semiconductor chip such as an LD 11 is attached to the stem 16
Since it is not possible to exchange electrical signals between the semiconductor chip and the outside simply by performing die bonding to fix it above,
Wire bonding is performed to electrically connect the semiconductor chip and the stem 16. After the wire bonding process is completed, in order to avoid physical contact between the semiconductor chip provided on the stem 16 and the outside, an operation called a cap seal for sealing the semiconductor chip with the cap 15 is performed.

After the cap sealing process is completed, a deterioration acceleration test called a burn-in test is performed. this is,
This is a deterioration test that is performed under more severe conditions than the actual semiconductor usage conditions. Following the burn-in test, electrical characteristics,
Inspect characteristics such as optical characteristics. Finally, cap 1
Work to fix the HOE 13 at the optimum position on 5.

In the above manufacturing method, in the hologram laser device 21, the HOE 13 is placed on the upper surface of the cap 15, and the HOE 13 is optically arranged so that the light emitted from the LD 11 and reflected by the information recording medium is accurately incident on the PD 14. Since it is necessary to fix the HOE 13 to the cap 15 after adjusting the position to the optimum position and adjusting the position to the optimum position, there is a problem that a large number of manufacturing steps are required.

As a conventional example of a hologram laser device for solving such a problem, a "semiconductor laser cap" disclosed in Japanese Patent Laid-Open No. 3-44992 is disclosed. This will be described below as a second conventional example. Second
Since the configuration and the function of the hologram laser device in the conventional example are substantially the same as those of the hologram laser device 21 in the first conventional example described above, only the differences will be described.
Other description is omitted.

FIG. 4 is a sectional view of a semiconductor laser cap which is a part of a conventional hologram laser device. In the second conventional example, as shown in FIG. 4, a hologram pattern 17, which is a diffraction grating, is formed on the outer surface or both surfaces of the top of the cap 15. Therefore, the cap 15
Simply adjust the position when joining the
The light emitted from D11 and reflected by the information recording medium is
The light can be accurately incident on the PD 14 via the hologram pattern 17.

From the above, since the cap 15 including the hologram pattern 17 can be molded at one time, the optical position adjustment of the hologram pattern 17 and the joining of the cap 15 and the stem 16 must be performed in the same step. It is possible to reduce the number of manufacturing steps.

[0013]

In the hologram laser device of the second conventional example, since the inner shape of the cap 15 is concave, a hologram pattern is formed on the inner surface of the top of the cap 15 by photolithography, etching or the like. There is the problem that forming 17 is very difficult.

An object of the present invention is to provide a cap-integrated hologram optical element, a hologram laser device, and a manufacturing method which can easily form a diffraction grating on both surfaces and reduce the number of manufacturing steps.

[0015]

According to the present invention, there is provided a hologram substrate forming step of forming a plurality of diffraction gratings on both sides of a first substrate, and a plurality of through holes corresponding to the diffraction gratings. A cap substrate forming step of forming a second substrate, a bonded substrate forming step of bonding the first substrate and the second substrate to each other to form a bonded substrate, and dicing the bonded substrate. And a dividing step of dividing into a plurality of cap-integrated hologram optical elements.

According to the present invention, a first substrate having a plurality of diffraction gratings formed on both sides thereof is formed on both sides of the substrate, and a second substrate having a plurality of through holes corresponding to the diffraction gratings of the first substrate.
The cap-integrated hologram optical element in which the diffraction grating and the cap are integrated can be easily manufactured only by dicing the bonded substrate formed by bonding the substrate and the substrate.

Further, according to the present invention, a semiconductor laser element serving as a light source and a light receiving element for receiving light emitted from the semiconductor laser element and reflected by an information recording medium are provided at a predetermined position on a stem having an input / output terminal. The step of fixing, the wire bonding step of electrically connecting the stem to the semiconductor laser element and the light receiving element,
A hologram including a step of manufacturing a cap-integrated hologram optical element by the manufacturing method according to claim 1 and a step of fixing the cap-integrated hologram optical element manufactured by the manufacturing method according to claim 1 on the stem. It is a method of manufacturing a laser device.

According to the present invention, the cap sealing step and the step of fixing the hologram optical element to the cap are performed in one step by using the cap integrated hologram optical element in which the diffraction grating and the cap are integrated. Therefore, the number of manufacturing steps of the hologram laser device can be reduced, and the manufacturing cost can be reduced accordingly.

Further, the present invention comprises a rectangular parallelepiped hologram element having a pair of diffraction gratings formed on both sides thereof, and a rectangular tubular cap bonded to the hologram element and having the same planar shape as the hologram element. This is a cap-integrated hologram optical element.

According to the present invention, the cap-integrated holographic optical element is formed by bonding the holographic optical element and the cap to each other, so that no troublesome optical position adjustment between the holographic optical element and the cap is required.
It can be easily manufactured.

The present invention is also a hologram laser device characterized in that a semiconductor laser element and a light receiving element are provided in the cap of the cap-integrated hologram optical element according to claim 3.

According to the present invention, the hologram laser device can be easily manufactured and the manufacturing cost can be reduced by using the hologram optical element integrated with the cap.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION A method of manufacturing a cap-integrated hologram optical element 8 (hereinafter referred to as a cap-integrated HOE) according to a first embodiment of the present invention will be described. Figure 1
[Fig. 4] is a schematic view showing a method of manufacturing the cap-integrated HOE 8 As shown in FIG. 1A, on both surfaces of the first substrate 1,
A plurality of diffraction gratings 4 called pairs of holograms on both sides are formed, and a second substrate 2 having a plurality of through holes 5 corresponding to the diffraction gratings 4 of the first substrate 1 is formed.

In the present embodiment, the material used for the first substrate 1 and the second substrate 2 is, for example, acrylic resin which is a thermoplastic resin. Acrylic resins are used for impact resistance because of their high transparency and considerably high surface hardness. In addition, there are advantages that strength and rigidity are large, and machining and thermal processing are easy.

The hologram optical element (HOE) is arranged away from the LD by giving appropriate wavefront conversion to the light emitted from the semiconductor laser element (LD) and reflected by the information recording medium to diffract it. It is used to guide light to a light receiving element (PD). The HOE is usually manufactured by an injection molding machine using a precision mold master (stamper) for forming a narrow groove, or by using an etching technique. In this embodiment, a method for manufacturing an HOE using an etching technique will be described.

First, the substrate on which the hologram is formed is washed with a chemical solution or the like. After the cleaning process is completed, a photosensitive resin called photoresist is applied on the substrate. The substrate coated with the photoresist is subjected to light baking called pre-baking in order to remove the solvent in the photoresist and improve the adhesion with the substrate. Next, the substrate coated with the photoresist is covered with a photomask and exposed to light such as ultraviolet rays. The exposed substrate is PEB
After undergoing a light heat treatment called (post-exposure baking),
Perform development processing. In the development using a positive type resist, the photoresist in the portion irradiated with light such as ultraviolet rays is dissolved in the developing solution, and the photoresist pattern in the unexposed portion remains.
Further, in the development with the negative type resist, the photoresist in the non-irradiated portion is melted and the photoresist in the irradiated portion remains.

After the development process is completed, an etching process is performed in order to form a groove in the portion of the substrate where the photoresist has melted and disappeared. In this embodiment, a process by reactive ion etching, which is the most general dry etching method, will be described. In the reactive ion etching, a substrate is placed in a vacuum chamber (chemical reaction chamber) and a necessary etching gas is introduced. This gas is turned into plasma by an electric field or magnetic field. In the plasma, charged particles such as positive and negative ions and electrons, and neutral active species are mixed, and when etching species are adsorbed on the substrate to form a film, a chemical reaction occurs on the substrate surface, and etching products Is separated from the surface of the substrate and exhausted to the outside, and etching proceeds. This etching method is suitable for processing a fine pattern because it is easy to obtain a vertical sectional shape without side etching due to the action of a chemical reaction. After performing the etching process, the photoresist remaining on the substrate is removed to form a hologram.

Next, a method of forming the second substrate 2 by injection molding, which has a high molding speed and is a typical molding method of a thermoplastic resin, will be described.

First, a thermoplastic resin such as an acrylic resin as a raw material is put into a cylinder of an injection molding machine. next,
Push it forward with the screw in the cylinder and send it to the front of the cylinder while melting the acrylic resin with the heater. When the melted liquid acrylic resin reaches a specified amount in the cylinder, the screw plays the role of a piston and applies pressure to the acrylic resin, and the nozzle at the tip of the cylinder presses the acrylic resin into the mold at a fixed amount, Inject the liquid acrylic resin.

The mold here is made of a strong metal and has an internal space (cavity) of the same shape as the desired molded product.
It is a type that has. That is, a molded product having a desired shape can be formed by a mold attached to an injection molding machine, and injection molded products having various shapes can be obtained depending on the difference in cavity. Therefore, in the step of forming the second substrate 2 in the present embodiment, a mold suitable for forming the second substrate 2 having the plurality of through holes 5 is prepared and attached to the injection molding machine in advance.

Next, when the high temperature liquid acrylic resin is injected into a mold having a low temperature, the acrylic resin is cooled and solidified or cured. When the mold is separated after being solidified or cured, the acrylic resin product having a desired shape can be taken out. By repeating the above operation, injection molding is continuously performed and the second substrate 2 is formed.

After the first substrate 1 which is a hologram substrate and the second substrate 2 which is a cap substrate are formed, FIG.
As shown in (b), the bonded substrate 3 forming step of bonding the first substrate 1 and the second substrate 2 and forming the bonded substrate 3 is performed.

In this step, a first substrate 1 having a plurality of paired holograms 4 on both sides of the substrate and a plurality of through holes 5 corresponding to the diffraction grating 4 formed on the first substrate 1 are formed. The second substrate 2 is attached. At this time, an acrylic UV (ultraviolet) resin is used as the adhesive.
Acrylic UV resin is a kind of ultraviolet curable resin and has a property of being instantly cured when irradiated with ultraviolet rays. Therefore, after applying the acrylic UV resin to at least one of the first substrate and the second substrate, the diffraction grating 4 and the through hole 5 are aligned and irradiated with ultraviolet rays to be cured to thereby bond the substrates. The laminated substrate 3 is formed.

Then, a dividing step is performed. In this step, the bonded substrate stack 3 is diced into a plurality of cap-integrated HOEs 8. FIG. 1C is a perspective view of the divided cap-integrated HOE 8.

By following the above steps, FIG.
As shown in (c), a cap integrated type having a rectangular parallelepiped HOE 6 on which diffraction gratings 4 forming a pair on both sides are formed, and a square tubular cap 7 bonded to the HOE 6 and having the same planar shape as the HOE 6 HOE8 is manufactured.

By using the method for manufacturing the cap-integrated HOE 8 as described above, the cap-integrated HOE 8 having the diffraction gratings 4 formed on both sides can be easily manufactured.

Next, a method for manufacturing a hologram laser device using the cap-integrated HOE 8 according to the second embodiment of the present invention will be described.

First, a work called die bonding for fixing the LD 11 and the PD 14 to each other at a predetermined position on the stem 16 having the input / output terminal is performed. At this time, the LD 11 and the PD 14 are fixed onto the stem by using a paste-like material obtained by adding about 80% of silver to an epoxy resin which is a kind of thermosetting resin, that is, a silver paste. The LD 11 and PD 14 are optically adjusted,
Fix in optimal position on stem 16. LD11 and P
Since the electric signal cannot be exchanged between the semiconductor chip and the outside only by fixing the semiconductor chip such as D14 on the stem 16, a work called wire bonding for electrically connecting the semiconductor chip and the stem 16 with a fine gold wire or the like. I do. The cap-integrated HOE 8 is manufactured by the above-described cap-integrated HOE 8 manufacturing method.

Next, a deterioration acceleration test called a burn-in test is performed. This is a deterioration test performed under more severe conditions than the actual semiconductor usage conditions. By setting the voltage and current of the semiconductor, which accelerates the deterioration, and the temperature and humidity of the operating environment more strictly than the normal operating conditions,
The deterioration of parts and equipment is promoted to carry out inspections such as life prediction and failure rate prediction. In addition, following the burn-in test, characteristic tests such as electrical characteristics and optical characteristics are performed. Finally, in order to avoid physical contact between the semiconductor chip provided on the stem 16 and the outside, the cap-integrated HOE 8 is fixed to the stem 16.

Through the above steps, the cap integrated HOE
A hologram laser device in which the LD 11 and the PD 14 are provided in the cap 7 of 8 is manufactured.

As described above, by using the cap-integrated HOE 8 in which the diffraction grating 4 and the cap 7 are integrated, the HOE 1 is applied to the cap sealing step and the cap 15.
Since the step of fixing 3 can be performed in one step,
The number of manufacturing steps of the hologram laser device can be reduced, and the manufacturing cost can be reduced accordingly.

[0042]

As described above, according to the present invention, a cap-integrated hologram optical element in which a diffraction grating and a cap are integrated can be easily manufactured.

Further, according to the present invention, the number of manufacturing steps of the hologram laser device can be reduced, and the manufacturing cost can be reduced accordingly.

Further, according to the present invention, a troublesome optical position adjustment between the hologram optical element and the cap is unnecessary, and the cap-integrated hologram optical element can be easily manufactured.

Further, according to the present invention, the hologram laser device can be easily manufactured and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic view showing a method of manufacturing a hologram optical element with a cap according to the present invention.

FIG. 2 is a diagram showing a structure of a conventional hologram laser device.

FIG. 3 is a schematic view showing a manufacturing process in a conventional hologram laser device.

FIG. 4 is a cross-sectional view of a semiconductor laser cap that is a part of a conventional hologram laser device.

[Explanation of symbols]

1st substrate 2 Second substrate 3 Laminated substrate 4 diffraction grating 5 through holes 6,13 Hologram optical element 7,15 cap 8 Cap integrated hologram optical element 11 Semiconductor laser device 12 monitor submount 14 Photodiode 16 stems 17 Hologram pattern 21 Hologram laser device

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H049 AA03 AA13 AA25 AA31 AA37                       AA55 AA57 AA66 AA68 CA01                       CA05 CA07 CA08 CA11 CA15                       CA20 CA28                 5D119 NA04 NA05                 5D789 NA04 NA05                 5F073 AB21 AB25 BA04 FA02 FA30

Claims (4)

[Claims] 1. A hologram substrate forming step of forming a plurality of diffraction gratings on both sides of a first substrate, and a second substrate having a plurality of through holes corresponding to the diffraction gratings. A cap substrate forming step; a bonded substrate forming step of bonding the first substrate and the second substrate to each other to form a bonded substrate; and dicing the bonded substrate to form a plurality of cap integrated types. A method of manufacturing a holographic optical element integrated with a cap, comprising a step of dividing into holographic optical elements. 2. A step of fixing a semiconductor laser element serving as a light source and a light receiving element for receiving light emitted from the semiconductor laser element and reflected by an information recording medium, at a predetermined position on a stem having an input / output terminal. A wire bonding step of electrically connecting the stem to the semiconductor laser element and the light receiving element; a step of manufacturing a cap-integrated hologram optical element by the manufacturing method according to claim 1; 1. A method of manufacturing a hologram laser device, comprising the step of fixing a hologram optical element integrated with a cap manufactured by the manufacturing method according to 1. 3. A cap integrated type having a rectangular parallelepiped hologram element having a pair of diffraction gratings formed on both sides thereof, and a square tubular cap bonded to the hologram element and having the same planar shape as the hologram element. Hologram optical element. 4. A hologram laser device, wherein a semiconductor laser element and a light receiving element are provided in a cap of the cap-integrated hologram optical element according to claim 3.