JP2010237301A - Optical member, method of manufacturing optical device, and optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily manufacture an optical member having a reflecting surface having an optional angle or a curved surface, and an optical device using the optical member. <P>SOLUTION: In this method of manufacturing the optical member, a photoresist 6 is applied to a surface 5a of a silicon substrate 5, an opening 6h of a necessary shape is formed, the photoresist 6 is used as an etching mask, and etching is performed in a direction perpendicular to the surface 5a of the silicon substrate 5. A recess 5h is formed that includes two stepped and parallel planes 51a and 51b perpendicular to the surface 5a and a slope 5c for connecting two planes. The slope 5c defining a part of the inner wall surface of the recess 5h is coated with a reflecting metal film, and a reflecting surface is formed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an optical member having at least a reflective surface using a silicon substrate or a silicon wafer, a method for manufacturing an optical device using the optical member, and the optical device.

Various optical devices used for an optical device for realizing optical communication, optical interconnection, etc., or an optical pickup for recording information on a recording medium such as a CD or a DVD or reading the recorded information, An optical member having a reflecting surface (mirror) is often used.
Further, as such an optical apparatus, an optical member having a reflecting surface, a light emitting device such as a semiconductor laser or a light emitting diode, a light receiving device such as a photodiode, a phototransistor, or a CCD, a light guiding device, or SHG (second harmonic) 2. Description of the Related Art Conventionally, an optical apparatus provided with an optical device such as a wavelength conversion device such as a generating element, in which light emitted from a light emitting device is reflected by a reflection surface and enters the optical device.

  For example, in Patent Document 1, an elliptical curved surface mirror is formed on a silicon substrate, and light emitted from a light emitting device such as a surface emitting laser mounted on the silicon substrate is reflected by the elliptical curved surface mirror. An optical apparatus configured to be incident on a light receiving device or a waveguide provided on a substrate is disclosed.

  In Patent Document 2, a recess is formed by digging part of a light receiving element substrate made of silicon or GaAs and provided with a light receiving element such as a photodiode, and a mirror member is formed on the bottom surface of the recess. An optical device configured to reflect a laser beam emitted from a semiconductor laser mounted on a light receiving element substrate at a substantially right angle by the reflecting surface of the mirror member and emit the laser beam toward a recording medium is disclosed. Has been.

JP 2001-141965 A JP 2005-340408 A

  However, it is extremely difficult for the optical apparatus described in Patent Document 1 to always form an elliptical curved mirror having a predetermined shape on a silicon substrate, and a light emitting device such as a surface emitting laser mounted on the silicon substrate. The light receiving device or waveguide must be positioned and arranged so that the light emitting point and the light receiving point coincide with the two focal points of the elliptical curved mirror, respectively, and adjustment and arrangement require skilled techniques. There was a problem.

  On the other hand, in the optical device described in Patent Document 2, a recess is formed in a light receiving element substrate on which a light receiving element is provided, and a mirror member whose reflection surface forms an angle of 45 ° with respect to the bottom surface on the bottom surface of the recess. Must be created and installed separately. However, conditions for forming a reflective surface at a 45 ° angle by anisotropic etching on a semiconductor such as a silicon substrate are limited. For example, as a mirror member, the crystal axis is [110] with respect to the (100) plane. A silicon substrate manufactured so as to be inclined approximately 9.7 ° in the direction is etched with KOH (potassium hydroxide) or THMA (tetramethylammonium hydroxide), and a reflective film is formed on the inclined surface formed by the etching. The method of vapor-depositing is taken.

  In such a method, there is a problem that the material of the mirror member is limited, and a separately created mirror member must be bonded to a predetermined position of the concave portion of the light receiving element substrate. There was also the problem of becoming a factor.

  The present invention has been made in view of such a current situation, and an object thereof is to easily manufacture an optical member having a reflecting surface having an arbitrary angle or curved surface, and an optical device using the optical member. And Another object of the present invention is to provide an inexpensive optical apparatus in which a light emitting device and an optical device such as a light receiving device, a light guiding device, or a wavelength conversion device are linked through a reflecting surface.

  In order to achieve the above object, the basic method of manufacturing an optical member according to the present invention includes a recess including a surface perpendicular to a surface of the silicon substrate by etching in a direction perpendicular to the surface. And a reflective surface is formed by covering the perpendicular surface with a reflective metal film.

  The etching may be performed by anisotropic dry etching using a photoresist applied to the surface of the silicon substrate and having the same opening or notch as the planar shape of the recess as an etching mask. The reflective metal film can be coated on the vertical surface by oblique deposition or tilt sputtering using silver, aluminum, or gold from the surface side of the silicon substrate.

  A more preferable method of manufacturing an optical member according to the present invention includes etching from a surface of a silicon substrate in a direction perpendicular to the surface, and two planes perpendicular to the surface and slopes connecting the two planes. A concave portion is formed, and a reflective metal film is coated on the inclined surface to form a reflective surface.

The two planes are stepped and parallel to each other, and the reflecting surface can form an angle of 45 ° with respect to the two planes.
The above etching can be performed by anisotropic dry etching in the same manner as described above, but it is etched with a gas obtained by diluting a sulfur fluoride gas with oxygen, and a sidewall protective film forming process with a fluorocarbon gas. It is good to carry out by the Bosch method which repeats.
The reflective metal film can be coated on the slope by oblique vapor deposition or tilt sputtering using silver, aluminum, or gold, as described above.

  The method of manufacturing an optical apparatus according to the present invention uses an optical member manufactured by the latter manufacturing method, and uses a light emitting device on one of the two planes and an optical device such as a light receiving device, a light guiding device, or a wavelength conversion device on the other. Each device is positioned and fixed, and the light emitted from the light emitting device is reflected by the reflecting surface so as to enter the optical device.

  An optical apparatus according to the present invention includes an optical member manufactured by the latter manufacturing method, a light emitting device positioned and fixed on one of the two planes formed on the optical member, and a light receiving device positioned and fixed on the other. The optical apparatus includes an optical device such as a light guide device or a wavelength conversion device, and is configured such that light emitted from the light emitting device is reflected by the reflection surface and enters the optical device.

The method of manufacturing an optical member according to the present invention further uses a silicon wafer as the silicon substrate, performs etching from the surface of the silicon wafer in a direction perpendicular to the surface, and the concave portion is formed in a longitudinal direction and a short shape of the planar shape. A plurality of layers are aligned in the hand direction, and the reflective surfaces are formed by covering the slopes of the recesses with a reflective metal film.
Thereafter, the silicon wafer is cut along the longitudinal direction while leaving a predetermined width of the silicon wafer on the wall surface side composed of the two flat surfaces of the recesses and the reflecting surface, and the wall surface facing the wall surface is removed. Cut along the longitudinal direction to form a plurality of strip-shaped members in which a plurality of optical members are continuous in the longitudinal direction, and each strip-shaped member is removed from each wall surface forming a pair of short sides of each of the recesses. In this way, each optical member is cut along the short direction.

An optical device manufacturing method according to the present invention using this optical member manufacturing method has the following steps.
(A) Etching is performed from the surface of the silicon wafer in a direction perpendicular to the surface, and a recess including two planes perpendicular to the surface and a slope connecting the two planes is formed in the longitudinal direction of the plane shape. And a process of aligning and forming a plurality of each in the short direction,
(B) a step of forming a reflective surface by covering the inclined surface of each concave portion with a reflective metal film,
(C) Thereafter, the silicon wafer is cut along the longitudinal direction while leaving a predetermined width of the silicon wafer on the wall surface formed by the two planes and the reflecting surface of each recess, and the wall surface facing the wall surface is cut. Cutting along the longitudinal direction so as to remove, and a plurality of optical members made into a plurality of strip-shaped members continuous in the longitudinal direction,
(D) A light emitting device on one of the two planes and a light receiving device, a light guiding device on the other, or a portion serving as an optical member of each optical apparatus provided with the two planes and the reflecting surface of each strip-shaped member. A step of positioning and fixing an optical device such as a wavelength conversion device, so that light emitted from the light emitting device is reflected by the reflecting surface and enters the optical device;
(E) Thereafter, each strip-shaped member is cut along the lateral direction so as to remove the respective wall surfaces forming a pair of short sides of each of the recesses, thereby forming individual optical devices,

  In the method of manufacturing an optical member according to the present invention, a recess is formed by etching in a direction perpendicular to the surface of the silicon substrate, and a reflective metal film is formed on a required inner wall surface perpendicular to the surface of the recess. Since the reflective surface is formed by covering, a reflective surface having an arbitrary angle or curved surface can be easily formed depending on the shape of the opening or notch of the etching mask.

In addition, an optical member in which two planes serving as a mounting surface of the optical component are formed simultaneously with the reflecting surface can be easily manufactured by the shape of the opening or notch of the etching mask.
Furthermore, by using the optical member, an optical device in which a light emitting device and an optical device such as a light receiving device, a light guide device, or a wavelength conversion device are linked through a reflecting surface can be easily manufactured.
A large number of optical members and optical devices can be simultaneously manufactured from a single silicon wafer.

It is a front view which shows one Example of the optical apparatus manufactured with the manufacturing method of this invention using the optical member. It is sectional drawing which follows the XX line of FIG. It is the bottom view seen from the arrow A direction of FIG. It is a front view which shows the 1st process for obtaining the silicon substrate used in order to manufacture the optical member by this invention. It is a front view which similarly shows the 2nd process. It is a front view which similarly shows the 3rd process. It is a longitudinal cross-sectional view which shows the 1st process for demonstrating 1st Example of the manufacturing method of the optical member by this invention. It is a longitudinal section showing the 2nd process similarly. It is a top view of the stencil mask in FIG.

It is a figure which shows the 3rd process following FIG. 8, (b) is a top view, (a) It is sectional drawing which follows the AA line. FIG. 11 is a sectional view and a plan view similar to FIGS. 10A and 10B showing the fourth step. FIG. 11 is a sectional view and a plan view similar to FIGS. 10A and 10B showing the fifth step. It is a figure which similarly shows the 6th process, (b) is a top view, (a) It is sectional drawing which follows the AA line. FIG. 14 is a sectional view and a plan view similar to FIGS. 13A and 13B showing the seventh step. It is the same sectional drawing and top view as Drawing 13 (a) and (b) showing the 8th process similarly. It is an enlarged plan view which shows the dicing line of the silicon substrate for cutting out an optical member. It is a top view of the cut-out optical member. FIG. 18 is a perspective view showing the optical member of FIG. 17 further enlarged in a state where the optical member is rotated 180 ° counterclockwise.

It is a perspective view which shows the completion state of an etching in the case of manufacturing a some optical member simultaneously from one silicon wafer. FIG. 20 is a perspective view of a strip-shaped member in which two optical members obtained by cutting along each dicing line indicated by a dashed line in FIG. 19 are continuous in the longitudinal direction. It is the front view (a) and the top view (b) of the state which made the strip-shaped member shown in FIG. It is the front view (a) and the top view (b) of the state which attached the optical component to the strip-shaped member shown in FIG. It is the front view (a) and top view (b) of one optical apparatus obtained by cut | disconnecting the strip-shaped member shown in FIG. 21 with each dicing line shown with a dashed-dotted line. It is a front view which shows the example which changed the shape of the optical member of the optical apparatus shown in FIG.

It is a top view which shows the reflective surface creation process in the manufacturing method of the optical member which provided only the inclined planar reflective surface. It is sectional drawing which follows the BB line in FIG. It is a perspective view of the optical member which provided only the completed flat planar reflective surface. It is a top view which shows the reflective surface creation process in the manufacturing method of the optical member which provided only the elliptical cylindrical surface-shaped reflective surface. It is sectional drawing which follows the CC line in FIG. It is a perspective view of the optical member which provided only the completed elliptical cylindrical surface-shaped reflective surface. It is a perspective view similar to FIG. 19 which shows the example of a change of the manufacturing method of the optical member by this invention.

Hereinafter, embodiments for carrying out the present invention will be specifically described with reference to the drawings.
[One Example of Optical Device]
First, an embodiment of an optical device using an optical member manufactured by the manufacturing method of the present invention described later will be described with reference to FIGS. 1 is a front view of the optical device, FIG. 2 is a cross-sectional view taken along the line XX of FIG. 1, and FIG. 3 is a bottom view seen from the direction of arrow A in FIG.

  In this optical device, an optical component is mounted on an optical member 1 having a reflective surface 13 formed from a silicon (Si) substrate. That is, a laser diode 2 that is a semiconductor laser generation element is mounted as a light emitting device, and a second harmonic generation (SHG) element 3 that is a wavelength conversion device is mounted as an optical device.

The optical member 1 includes an upper mounting surface 11 and a lower mounting surface 12 that are two parallel and different planes, and an inclined surface that connects the two planes, such as aluminum (Al), silver (Ag), gold (Au), or the like. It consists of a main body 10 having a reflective surface (mirror) 13 covered with a reflective metal film, and a wall 15 extending in a rectangular shape upward from the rear surface of the main body 10 in FIG. As shown in FIG. 2, the wall 15 has a silicon dioxide (SiO ₂ ) film 15b coated on the surface of the silicon layer 15a.

  As shown in FIG. 1, the laser diode 2 is positioned and placed on the upper placement surface 11 of the main body portion 10, and is fixed to the upper placement surface 11 and the wall portion 15 with an adhesive (not shown). In FIG. 1, a predetermined portion on the right end side extends and extends on the reflection surface 13, and the light emitting portion 2a is provided on the lower surface of the portion.

A heat dissipating submount (a substrate made of Si or AlN) 4 is placed on the laser diode 2, and is fixed to the upper surface of the laser diode 2 and the wall portion 15 by an adhesive (not shown). . In order to improve heat dissipation, it is desirable to use a metallic adhesive such as silver paste as any of the above adhesives.
The heat generated in the laser diode 2 is radiated from the lower surface to the main body 10 and is radiated from the upper surface to the wall 15 through the submount 4.

On the other hand, the SHG element 3 which is a wavelength conversion device is positioned and placed on the lower placement surface 12 of the main body 10 with one end surface 3a facing the reflection surface 13, and silver is placed on the lower placement surface 12 and the wall portion 15. It is fixed with heat conductive adhesive such as paste.
The reflection surface 13 has an inclination angle θ of 45 ° with respect to an extension line of the upper mounting surface 11 and the lower mounting surface 12 which are parallel to each other.

  Then, the laser light emitted from the light emitting portion 2a of the laser diode 2 toward the reflecting surface 13 substantially vertically downward is reflected by the reflecting surface 13, deflected by 90 °, and redirected in a substantially horizontal direction. Is incident on one end surface 3a which is a light receiving surface. The wavelength of the laser light incident on the SGI element 3 is converted by the SHG element 3 to 1/2 (the frequency is doubled) and emitted from the other end surface 2b. For example, when the wavelength of the laser beam emitted from the laser diode 2 is 1064 nm, the wavelength of the laser beam emitted from the SHG element 3 is 532 nm.

As shown in FIG. 3, the width of the laser diode 2 and the SHG element 3 is wider than the width of the upper placement surface 11 and the lower placement surface 12 of the main body portion 10, and the side where the wall portion 15 of the main body portion 10 is not present. It protrudes in the width direction. In this way, terminals for wiring can be provided at the protruding portions on the back surfaces of the laser diode 2 and the SHG element 3 as exemplified by T1 and T2, and wiring with other devices is wire-bonded. Etc. can be easily performed.
This optical device (laser light source using an SHG element) can be used for a laser module for a light source such as a small projector. In addition, it is possible to provide an inexpensive and compact laser module that is simple in structure and easy to manufacture.

  As the light emitting device, a light emitting diode (LED) or other light emitting device may be used instead of the laser diode. As the other optical device, a light receiving device such as a phototransistor or a photodiode, a light guiding device such as a waveguide such as an optical fiber, a Selfoc lens (registered trademark), or the like can be used instead of the SHG element. .

  In addition, a laser diode that emits light from the end surface can be used. In this case, the laser diode is mounted on the lower mounting surface 12, and the laser light emitted from the tip surface is reflected by the reflecting surface 13. The light is emitted directly upward, or an optical device such as a light receiving device or a light guiding device is provided so as to protrude from the upper mounting surface 11 onto the reflecting surface 13 or fixed to the wall portion 15. The reflected laser beam may be incident on the optical device. The upper placement surface 11 and the lower placement surface 12 do not necessarily have to be parallel to each other, and the inclination angle of the reflection surface 13 with respect to these surfaces is not limited to 45 °.

[First Example of Manufacturing Method of Optical Member]
Next, a description will be given of a first embodiment of a method for manufacturing an optical member used in the above-described optical apparatus according to the present invention.
First, the process for obtaining the silicon substrate used for the manufacturing method of the optical member by this invention is demonstrated with reference to FIGS. Each of these figures is a front view seen from a direction parallel to the surface of the silicon substrate.

FIG. 4 shows the first step, and a first silicon (Si) substrate 51 and a second silicon (Si) substrate 52 having the same size are prepared. The first silicon substrate 51 is a substrate made of only silicon, and the entire surface of the second silicon substrate 52 is oxidized to form a silicon dioxide (SiO ₂ ) film 53.

FIG. 5 shows the second step, and the first silicon substrate 51 and the second silicon substrate 52 are joined by surface activation with the silicon dioxide film 53 interposed therebetween, as in the case of manufacturing an SOI substrate.
FIG. 6 shows a third step, in which the second silicon substrate 52 is polished from the surface side where the silicon dioxide film 53 is not formed to reduce its thickness, which is necessary as the wall portion 15 of the optical member 1 described above. Just leave. Thus, the silicon substrate 5 provided with the silicon dioxide film 53 functioning as an etching stopper can be prepared.

Therefore, a method of manufacturing the optical member 1 using the silicon substrate 5 will be described in the order of steps with reference to FIGS.
First, in the first step, as shown in FIG. 7, a photoresist 6 which is a photosensitive resin is applied to the entire surface of the silicon substrate 5. A photoresist is a composition whose solubility in a developing solution is changed by light, electron beam or the like, and there are a negative type and a positive type. Here, a positive photoresist is used in which the solubility in a developer increases when exposed to light, and the exposed portion is removed by development.

  In the next second step, a photomask 7 is placed on the upper surface of the photoresist 6 as shown in FIG. The photomask 7 has an opening 7h as shown in FIG. The opening 7h is a substantially rectangular shape having a pair of long sides and a pair of short sides, but one of the pair of long sides (upper side in FIG. 9) is deformed. It consists of portions 7a and 7b and a 45 ° inclined side 7c connecting the two portions. Accordingly, the opening 7h includes a narrow portion, a wide portion, and a portion whose width changes. In some cases, the photomask 7 may be spaced apart from the upper surface of the photoresist 6 without being in close contact therewith.

Then, in the third step, when exposure is performed by irradiating ultraviolet rays from above in FIG. 8, the photoresist 6 is exposed only in the portion corresponding to the opening 7h of the photomask 7, and the solubility in the developer increases. Therefore, when developing with a developer using an alkaline solution, an opening 6h having the same shape as the opening 7h of the photomask 7 is formed in the photoresist 6 as shown in FIG. 10, and the surface 5a of the silicon substrate 5 is exposed only within the opening 6h. To do.
In FIG. 10, (b) is a plan view, and (a) is a cross-sectional view along the line AA. Also in the following FIGS. 11 to 15, (b) is a plan view, and (a) is a cross-sectional view similar to (a) of FIG.

In the next fourth step, using the photoresist 6 as an etching mask, the silicon substrate 5 is etched from the surface 5a in a direction perpendicular to the surface 5a, so that the inner wall surface 5b becomes the surface as shown in FIG. A concave portion 5 h that is perpendicular to 5 a and has the same planar shape as the opening 6 h of the photoresist 6 is formed. Since the silicon dioxide film 53 of the silicon substrate 5 functions as an etching stopper, the etching stops there, and only the first silicon substrate 51 is etched to form a hole-shaped recess.
And, the surface corresponding to the deformed long side of the inner wall surface 5b of the recess 5h of the silicon substrate 5 is parallel to the two flat surfaces 51a and 51b which are different from each other, and the inclined surface 51c which connects the two flat surfaces 51a and 51b. Consists of.

In this way, anisotropic dry etching is performed in this embodiment in order to etch the silicon substrate 5 in a direction perpendicular to the surface 5a. As a typical method, the Bosch method (also called gas chopping method) is used. ) This etching method enables highly anisotropic etching by alternately repeating the etching process and the sidewall protection process.
The etching process is performed using a gas obtained by diluting a sulfur fluoride-based gas such as sulfur hexafluoride (SF ₆ ) with oxygen (O ₂ ). In the side wall protection process, a side wall protective film is formed with a fluorocarbon gas such as C ₄ F ₈ .
For example, the etching process and the sidewall protection process are performed under the following conditions.

Etching treatment Side wall protection treatment SF ₆ 100sccm 0sccm
O ₂ 5sccm 0sccm
C ₄ F ₈ 0 sccm 100 sccm

RF power 400W 400W
Bias power 30W 0W
Time 10sec 5sec

Under the above conditions, the etching process is 10 seconds and the sidewall protection process is 1 cycle of 5 seconds, 0.5 μm is etched, and 800 cycles are required to cut 400 μm. “Sccm” under the above conditions is a flow rate (cc / min) normalized at a constant temperature such as 0 ° C. or 25 ° C. at atmospheric pressure (1.013 hPa).
As anisotropic dry etching other than the Bosch method, ion-induced accelerated etching in which argon (Ar) ions are bombarded in a state where the silicon surface is saturated with F atoms, or chlorine (Cl ₂ ) and argon ion irradiation is used. There are also etchings due to combined effects.

After this etching process, as shown in FIG. 12, in the fifth step, the photoresist 6 is removed by a stripping solution or ashing (ashing process) according to the used photoresist.
Further, since the inner wall surface 5b of the concave portion 5h of the silicon substrate 5 has fine stripe-like irregularities formed by the etching process, a flattening process using oxidation and HF gas is performed, and in particular, the flatness of the inclined surface 51c is increased.

  In the next sixth step, a metal stencil mask 8 is positioned and installed on the surface 5a of the silicon substrate 5 as shown in FIG. In the stencil mask 8, an opening 8h extending in a direction perpendicular to the inclined surface 51c from a position corresponding to the inclined surface 51c is formed in a portion covering the concave portion 5h of the semiconductor substrate 5.

  In the seventh step, the silicon substrate 5 on which the stencil mask 8 is thus installed is put into a sputtering apparatus, and silver (Ag), aluminum (Al), or gold (Au) is used as a vapor deposition material or a sputtering material, and is parallel to FIG. As shown by three arrow lines, through the opening 8h of the stencil mask 8, oblique deposition or tilt sputtering is performed on the inclined surface 51c. As a result, the reflective metal film is selectively coated on the inclined surface 51c of the inner wall surface 5b of the recess 5h of the silicon substrate 5 to form the reflective surface 13 shown in FIG. It is preferable to prevent the metal film from being formed on other portions as much as possible so that the insulating property is not impaired when the optical component is mounted.

The reflective characteristics of the reflective surface differ depending on whether silver, aluminum, or gold is used as the material of the reflective metal film. Therefore, it is preferable to select a material for the reflective metal film in accordance with the light emission wavelength characteristics of the light emitting device (laser diode or LED).
Thereafter, when the silicon substrate 5 is taken out of the sputtering apparatus and the stencil mask 8 is removed in the eighth step, the result is as shown in FIG.

FIG. 16 is an enlarged plan view showing a dicing line of the silicon substrate for cutting out the optical member in the next ninth step from the silicon substrate 5 on which the reflecting surface 13 and the like are formed in this way.
Only the side where the flat surfaces 51a and 51b and the reflecting surface 13 of the concave portion 5h of the silicon substrate 5 are present is cut along the horizontal dicing line H1 while leaving the silicon substrate 5 of a portion to be the main body portion 10 of the optical member by a predetermined width. However, all other sides are cut along the horizontal dicing line H2 and the vertical dicing lines V1 and V2 that pass through the vicinity of the inside of the inner wall surface of the recess 5h. These cuttings are performed by a dicing saw.

FIG. 17 is a plan view of the cut-out optical member, and FIG. 18 is a perspective view showing the completed optical member of FIG. 17 further enlarged in a state rotated 180 ° counterclockwise. In these drawings, the names and symbols of the respective parts in the optical member 1 of the optical device described with reference to FIGS. 1 to 3 are used.
The optical member 1 includes a main body 10 and a wall 15, and the main body 10 has two flat surfaces that are different from each other and are part of the inner wall surface 5 b of the recess 5 h perpendicular to the surface 5 a of the silicon substrate 5 in FIG. 16. 51a and 51b become the upper mounting surface 11 and the lower mounting surface 12, and the reflective surface 13 which coat | covered the reflective metal film is provided in the inclined surface 51c between them.

The silicon layer 15a and the silicon dioxide film 15b constituting the rectangular wall portion 15 are the second silicon substrate 52 of the silicon substrate 5 and the silicon dioxide film 53 formed on the surface thereof in FIG.
Using this optical member 1, the optical device described with reference to FIGS. 1 to 3 can be easily manufactured.

  In the method of manufacturing an optical member according to the present invention, in order to form a surface to be a reflective surface on a silicon substrate, etching is performed in a direction perpendicular to the surface of the silicon substrate, so that the opening of the photoresist serving as an etching mask Since a plane perpendicular to the surface of the silicon substrate is formed by the planar shape, a slope or curved surface having an arbitrary angle can be formed regardless of the plane orientation of the silicon substrate and the direction of the crystal axis. In addition, a mounting surface for mounting an optical device such as a light emitting device can be formed simultaneously by etching.

  In the above-described embodiment, the silicon substrate 5 provided with the silicon dioxide film is used and the etching depth is regulated using the silicon substrate 5 as an etching stopper. However, the etching is performed using the silicon substrate not provided with the silicon dioxide film. The depth of etching can be controlled by time or the number of etching cycles by the Bosch method.

  Further, in the above-described embodiment, before cutting out a necessary part as an optical member from a silicon substrate having a concave portion having an inner wall surface perpendicular to the surface, oblique deposition or tilt sputtering is performed on a slope forming a part of the inner wall surface. The reflective metal film was coated to form the reflective surface, but after cutting out the necessary part as an optical member, the reflective surface was formed by coating the reflective metal film on the slope by vapor deposition or sputtering. Good.

[Second Embodiment of Manufacturing Method of Optical Member]
Next, a second embodiment of the optical member manufacturing method according to the present invention will be described with reference to FIGS.
In this embodiment, a plurality of (many) optical members are simultaneously manufactured from one silicon wafer, and a plurality of optical devices can be manufactured together.

  Therefore, as shown in FIG. 19, a silicon wafer 50 having a large diameter and a sufficient thickness is used as the silicon substrate. Similar to the silicon substrate 5 described with reference to FIGS. 4 to 6, the silicon wafer 50 is formed by bonding a silicon wafer made of only silicon and a silicon wafer having a silicon dioxide film formed on the surface thereof to form a silicon dioxide film. Although the wafer is polished to reduce the thickness, the layer configuration is not shown in FIG.

  Similar to the first embodiment described above, etching is performed from the surface 50a of the silicon wafer 50 in a direction perpendicular to the surface 50a, so that the concave portion 50h having the same shape as that of the first embodiment is formed in the longitudinal direction and the short direction of the planar shape. A plurality of each is aligned in the hand direction (in the example shown in FIG. 19, two in the longitudinal direction and three in the short direction), and formed on a slope forming a part of the inner wall surface of each recess 50h. Each of the reflective surfaces is covered with a reflective metal film. On both sides of the reflecting surface 13, two parallel and flat surfaces are formed which become the upper mounting surface 11 and the lower mounting surface 12.

The steps so far are the same as those of the first embodiment described above except that six concave portions are formed at the same time and the reflective metal film is coated on each inclined surface at the same time.
From this state, it cut | disconnects by each dicing line shown with a dashed-dotted line in FIG. 19, and it is set as the strip-shaped member which two optical members continued in the longitudinal direction. FIG. 20 is a perspective view of the strip-shaped member.
This strip-shaped member 60 is formed by replacing the silicon wafer 50 of FIG. 19 with a predetermined width on the wall surface side of the upper mounting surface 11, the lower mounting surface 12, and the reflecting surface 13 of each recess 50h. And along the longitudinal direction so as to remove the wall surface facing the wall surface.

In the thickness direction, there are a first silicon substrate 61 on which two sets of upper placement surface 11, lower placement surface 12 and reflection surface 13 are formed, and a second silicon substrate 62 on which a silicon dioxide film 63 is provided. It is pasted together. FIG. 21A is a front view showing the strip-shaped member 60 with the main body side facing down, and FIG. 21B is a plan view thereof.
If this strip-shaped member 60 is cut along the lateral direction so as to remove the respective wall surfaces forming the pair of short sides of each recess, the individual optical members 1 as shown in FIG. 18 can be obtained. .

However, in this embodiment, the strip-shaped member 60 remains, and as shown in FIG. 22, the laser diode 2 is positioned and fixed on each upper mounting surface 11, and the heat dissipating submount 4 is adhered thereon, The SHG element 3 is positioned and fixed on each lower placement surface 12, and each optical component of the two optical devices is attached. Alternatively, the laser diode 2 and the submount 4 integrated together may be fixed on each upper placement surface 11.
(A) of FIG. 22 is a front view showing the optical component mounting state, and (b) is a plan view thereof.

Then, if this strip-shaped member 60 is cut | disconnected in a transversal direction along each dicing line shown with a dashed-dotted line in FIG. 22, each optical apparatus will be completed. FIG. 23A is a front view of the optical device, and FIG. 23B is a plan view thereof.
This optical device is the same as the optical device described with reference to FIGS. 1 to 3 except that the SHG element 3 does not protrude outward from each lower mounting surface 12.

  In this embodiment as well, the etching depth can be controlled by using a silicon wafer not provided with a silicon dioxide film and by the etching time or the number of cycles of etching by the Bosch method. In addition, various optical components to be attached to configure the optical device can be changed.

[Modification example of optical member and optical device]
Here, FIG. 24 shows a modification of the optical member and the optical device according to the present invention. This optical device is an example in which the shape of the optical member of the optical device shown in FIG. 1 is partially changed, and is a front view showing a main body portion 10 ′ of the optical member 1 ′ in a longitudinal section. In this figure, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. Since the optical member and the main body are slightly different, they are designated as 1 'and 10'.

The main body portion 10 ′ of the optical member 1 ′ has an abutting step portion 11 a at the rear end portion of the upper placement surface 11, and an abutting step portion 12 a at the front end portion of the lower placement surface 12. Yes.
In this way, when the laser diode 2 is mounted on the upper placement surface 11 of the main body 10 ', the rear end surface of the laser diode 2 can be abutted against the abutting step 11a for positioning. Also, when the SHG element 3 is attached on the lower placement surface 12, the front end face of the SHG element 3 can be abutted against the abutting step 12a and positioned. Therefore, the laser diode 2 and the SHG element 3 can be positioned and fixed easily and accurately.

In order to provide the abutting step portions 11a and 12a, the abutting step portion is formed by slightly changing the opening pattern of the photoresist when a predetermined recess is formed on the silicon substrate or the silicon wafer by anisotropic dry etching. It suffices that the portions corresponding to 11a and 12a are not etched.
Further, the two planes (mounting surfaces) on which optical components such as the laser diode 2 and the SHG element 3 are placed do not necessarily have to be parallel to each other.

[Method for producing optical member provided with only reflecting surface]
The optical member manufacturing method according to the present invention can also manufacture an optical member provided with only a reflective surface (mirror). Therefore, a method for manufacturing an optical member provided with an inclined planar reflecting surface and an optical member provided with only an elliptical cylindrical reflecting surface will be briefly described below.
Since the processes up to the etching in the manufacturing method of these optical members and the method of forming the reflective metal film for forming the reflective surface are the same as those in the first embodiment, detailed description thereof is omitted. .

First, an example of a method for manufacturing an optical member provided with an inclined flat reflecting surface will be described with reference to FIGS.
As shown in FIG. 26, a photoresist 30 is applied to the surface 20a of the silicon substrate 20, and as shown in FIG. 25, square openings 31 are formed with each side inclined by 45 ° with respect to the side surface 20b of the silicon substrate 20. Then, using the photoresist 30 as an etching mask, the silicon substrate 20 is etched in a direction perpendicular to the surface 20a to form a hole-like recess 21 having a square planar shape and penetrating.

  The inner wall surface of the recess 21 is flattened, and a silver, aluminum, or gold reflective metal film is formed on one rectangular wall surface 21a constituting the inner wall surface by oblique vapor deposition or tilt sputtering from the surface side of the silicon substrate 20. Is used as the reflecting surface 23. In this case, the photoresist 30 can also be used as a mask for oblique deposition or tilt sputtering.

Thereafter, the photoresist 30 is removed, and the silicon substrate 20 is cut along the dicing lines L1, L2 and BB indicated by the alternate long and short dash lines in FIG. 25, thereby providing the inclined planar reflecting surface 23 shown in FIG. The optical member 1A is completed.
According to this manufacturing method, for example, the mirror member used in the optical device disclosed in Patent Document 2 can also be easily manufactured.
In this optical member 1A, the inclination angle θ of the reflection surface 23 with respect to the bottom surface 25 is set to 45 °, but a reflection surface having an arbitrary angle can be provided depending on the opening shape of the photoresist 30 and the dicing line.

Next, an example of a manufacturing method of an optical member provided with only an elliptical cylindrical surface will be described with reference to FIGS. 28 and 29, members corresponding to those in FIGS. 25 and 27 are denoted by the same reference numerals.
As shown in FIG. 29, a photoresist 30 is applied to the surface 20a of the silicon substrate 20, and as shown in FIG. 28, half and corners of an ellipse having a long axis parallel to the side surface 20b of the silicon substrate 20 are rounded. Patterning is performed so as to form an opening 32 having a shape connected to a square. Using the photoresist 30 as an etching mask, the silicon substrate 20 is anisotropically dry-etched in a direction perpendicular to the surface 20a to obtain a planar shape. A recess 22 that penetrates in the same planar shape as the opening 32 of the photoresist 30 is formed.

  The inner wall surface of the concave portion 21 is flattened, and a reflective metal film of silver or aluminum is formed on the elliptic cylindrical wall surface 22a constituting the inner wall surface by oblique deposition or tilt sputtering from the surface side of the silicon substrate 20. The reflective surface 24 is covered. Also in this case, the photoresist 30 can be used as a mask for oblique deposition or tilt sputtering.

Thereafter, the photoresist 30 is removed, and the silicon substrate 20 is cut along dicing lines L1, L2, and L3 indicated by alternate long and short dash lines in FIG. 28, so that the optical member provided with the reflecting surface 24 having the elliptic cylindrical surface shape shown in FIG. 1B is completed. The dicing line L3 is along the major axis direction of the elliptic cylindrical surface 22a.
According to this manufacturing method, for example, an optical member having an elliptical cylindrical surface (referred to as “elliptical spherical” in the same document) used in the optical apparatus disclosed in Patent Document 1 is also easily manufactured. be able to. The cylindrical curved surface shape and inclination of the reflecting surface can be arbitrarily changed depending on the opening shape of the photoresist 30 and the way of taking the dicing line.

  Also in these cases, after cutting out a necessary part as an optical member from a silicon substrate having a recess for forming a desired reflecting surface, the surface on which the reflecting surface is formed is coated with a reflective metal film. You may make it perform.

[Modification example of manufacturing method of optical member]
In the optical member manufacturing method according to the present invention, the shape of a photomask (see FIGS. 8 and 9) for exposing a photoresist serving as an etching mask is changed in each embodiment described with reference to FIGS. Thus, the shape of the etching mask can be variously changed. Accordingly, the shape of the recess formed in the silicon substrate (including the silicon wafer) can be variously changed. For example, a process of forming a notch-shaped recess is also possible.

  For example, with respect to the silicon wafer 50 shown in FIG. 19 of the second embodiment, an opening corresponding to the two recess formation positions on the right side of the photomask is formed by opening the long side portion on the straight line of the opening. If it is notched, the corresponding opening of the photoresist formed by photolithography using the same will be the same notch. When the photoresist 50 is used as an etching mask and etching is performed in the vertical direction from the surface 50a until it reaches the silicon dioxide film 53, a plurality of recesses 50h are formed simultaneously, as shown in FIG. It is formed in a notch shape. The other steps are the same as the processing method of the second embodiment described above.

Similarly, in other embodiments, if the opening formed in the photomask is notched, etching is performed using the photoresist formed thereby as an etching mask, so that the silicon substrate (including the silicon wafer) is notched. The process which forms a shape-shaped recessed part can be performed.
The present invention is not limited to the above-described embodiments, and it is needless to say that various modifications and applications can be made besides these.

  An optical member manufacturing method and an optical device manufacturing method according to the present invention include manufacturing of various optical members having a reflective surface using a silicon substrate, an optical device for realizing optical communication, optical interconnection, and the like, or a CD. It can be used in a wide variety of applications such as an optical pickup for recording information on a recording medium such as DVD and DVD, and reading out the recorded information, and various optical devices used for a light source of a small projector.

1, 1 ', 1A, 1B: Optical member 2: Laser diode (light emitting device)
3: Second harmonic generation (SHG) element (wavelength conversion element: optical device)
4: Submount 5, 20: Silicon substrate
5a, 20a: silicon substrate surface 5b: inner wall surface of recess 5h, 21, 22: recess formed in silicon substrate 6, 30: photoresist 6h, 31, 32: photoresist opening 7: photomask 7h: photomask 8: Stencil mask 8h: Stencil mask opening

DESCRIPTION OF SYMBOLS 10,10 ': Main-body part 11: Upper mounting surface 11a: Butting step part 12: Lower placing surface 12a: Butting step part 13,23,24: Reflecting surface 15: Wall part 40: Etching mask 50 : Silicon wafer 50a: Surfaces 50h and 50h 'of the silicon wafer: Recesses 51, 61 formed on the silicon wafer: First silicon substrate 51a, 51b: Plane 51c: Slope 52, 62: Second silicon substrate 53, 63: Silicon dioxide Film 60: strip-shaped member

Claims (12)

  Etching is performed from the surface of the silicon substrate in a direction perpendicular to the surface to form a recess including a surface perpendicular to the surface, and a reflective metal film is coated on the perpendicular surface to form a reflective surface. A method for producing an optical member.   The etching is performed by anisotropic dry etching using a photoresist coated on the surface of the silicon substrate and having the same opening or notch as the planar shape of the recess as an etching mask. The manufacturing method of the optical member of 1.   3. The optical member according to claim 1, wherein the reflective metal film is coated on the vertical surface by oblique deposition or tilt sputtering with silver, aluminum, or gold from the surface side of the silicon substrate. Manufacturing method.   Etching is performed from the surface of the silicon substrate in a direction perpendicular to the surface to form a recess including two planes perpendicular to the surface and a slope connecting the two planes, and the reflective metal film is formed on the slope. A method for producing an optical member, characterized in that a reflective surface is formed by covering the substrate.   5. The method of manufacturing an optical member according to claim 4, wherein the two planes are stepped and parallel to each other, and the reflection surface forms an angle of 45 ° with respect to an extension line of the two planes. .   The etching is performed by anisotropic dry etching using a photoresist coated on the surface of the silicon substrate and having the same opening or notch as the planar shape of the recess as an etching mask. The method for producing an optical member according to 4 or 5.   The anisotropic dry etching is performed by a Bosch method in which an etching process using a gas obtained by diluting a sulfur fluoride-based gas with oxygen and a sidewall protective film forming process using a fluorocarbon-based gas are alternately performed. The manufacturing method of the optical member of Claim 6.   The reflective metal film is coated on the inclined surface by oblique vapor deposition or tilt sputtering with silver, aluminum, or gold from the surface side of the silicon substrate. Manufacturing method of the optical member. Using an optical member manufactured by the method for manufacturing an optical member according to any one of claims 4 to 8,
Positioning and fixing a light emitting device on one of the two planes, and an optical device such as a light receiving device, a light guiding device, or a wavelength conversion device on the other,
A method for manufacturing an optical apparatus, wherein light emitted from the light emitting device is reflected by the reflecting surface and enters the optical device. An optical member manufactured by the method for manufacturing an optical member according to claim 4, a light emitting device positioned and fixed on one of the two planes formed on the optical member, and positioned on the other It consists of optical devices such as fixed light receiving devices, light guiding devices, or wavelength conversion devices,
An optical apparatus configured such that light emitted from the light emitting device is reflected by the reflecting surface and enters the optical device. It is a manufacturing method of the optical member according to any one of claims 4 to 8,
Using a silicon wafer as the silicon substrate,
Etching is performed in a direction perpendicular to the surface from the surface of the silicon wafer, and a plurality of the concave portions are aligned and formed in the longitudinal direction and the lateral direction of the planar shape,
After coating the reflective metal film on the inclined surface of each concave portion to form the reflective surface,
The silicon wafer is cut along the longitudinal direction while leaving a predetermined width of the silicon wafer on the wall surface composed of the two flat surfaces of the recesses and the reflecting surface, and the wall surface facing the wall surface is removed. And a plurality of strip-shaped members in which a plurality of optical members are continuous in the longitudinal direction.
A method for producing an optical member, characterized in that each strip-shaped member is cut along the lateral direction so as to remove each wall surface forming a pair of short sides of each concave portion, thereby forming individual optical members. . Etching is performed from the surface of the silicon wafer in a direction perpendicular to the surface, and a recess including two planes perpendicular to the surface and a slope connecting the two planes is formed in a longitudinal direction and a short side of the planar shape. A process of aligning and forming a plurality of each in the direction;
Forming a reflective surface by coating a reflective metal film on each of the slopes of the recesses; and
Thereafter, the silicon wafer is cut along the longitudinal direction while leaving a predetermined width of the silicon wafer on the wall surface side composed of the two planes of the concave portions and the reflecting surface, and the wall surface facing the wall surface is removed. Cutting along the longitudinal direction to make a plurality of strip-shaped members in which a plurality of optical members are continuous in the longitudinal direction;
A light emitting device on one of the two planes and a light receiving device, a light guiding device, or a wavelength on the other of the two planes on a portion to be an optical member of each optical apparatus provided with the two planes and the reflecting surface. A step of positioning and fixing an optical device such as a conversion device so that light emitted from the light emitting device is reflected by the reflecting surface and enters the optical device;
And then cutting each strip-shaped member along the short direction so as to remove each wall surface forming a pair of short sides of each concave portion to form individual optical devices. A method for manufacturing an optical device.

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