JPH11316311A - Waveguide type optical element and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waveguide type optical element having a high yield and its production method. SOLUTION: An optical function element 100 is provided with a ridge type optical waveguide 100c extended over a first element end face 100a and a second element and face 100b. In this optical function element 100, first and second element end faces 100a and 100b have such constitution that a buried layer 160 and a first electrode 150a are set back from the end face of the optical waveguide 100c. This constitution is realized by removing the buried layer 160 and the first electrode 150a placed in a cleavage area 190 before forming the first and second element end faces 100a and 100b by cleavage. As a result, the occurrence of small pieces of a passivation film 170, a polyimide 180, or the first electrode 150a, which hinder light incidence on and emission from the optical waveguide 100C at the time of cleaving the first and second element end faces 100a and 100b is reduced to improve the yield.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a waveguide type optical device and a method for manufacturing a waveguide type optical device.

[0002]

2. Description of the Related Art Conventionally, as a waveguide-type optical element, a device using a cut surface of an optical waveguide exposed on a cleavage plane as an optical input / output end surface has been widely used. Briefly, a cleavage step performed during the manufacture of such a waveguide type optical element will be described. First, a wafer on which an optical waveguide is formed is previously scratched along a crystal direction substantially perpendicular to the optical waveguide.
Next, the wafer having the scratches formed thereon is formed into a thin and loose sheet (hereinafter, referred to as a “substrate fixing sheet”).
The sandwich is sandwiched from above and below, and stress is applied only to the locations where cleavage is desired by applying pressure back and forth. Due to such stress, the wafer is broken along the crystal plane starting from the scratch, and the cut surface of the optical waveguide appears on the crystal plane, that is, the cleavage plane.

[0003] By repeatedly cleaving the wafer at predetermined intervals in this manner, a plurality of strip-shaped wafers (hereinafter, referred to as "bar wafers") having a plurality of optical waveguides substantially parallel to each other can be cut out. Further, by cutting a bar wafer in a direction substantially perpendicular to the cleavage plane by grouping a predetermined number of optical waveguides, a chip-shaped waveguide-type optical element can be formed.

In general, a striped laminated structure is applied to an optical waveguide of a waveguide type optical element. Such a laminated structure is formed, for example, by sequentially stacking a lower clad layer, a core layer, an upper clad layer, and an ohmic contact layer connected to another electrode on a semiconductor substrate to which electrodes are connected. In this way, when a laminated structure is formed, electric power supplied between the two electrodes from the outside is applied to the upper cladding layer and the lower cladding layer, respectively. Light processing, for example, light generation, light amplification, light modulation, light absorption, and the like can be performed.

Conventionally, a stripe-shaped optical waveguide (hereinafter, referred to as an optical waveguide)
It is called "stripe waveguide". Various configurations have been proposed. One of them is a ridge stripe waveguide in which the upper side of the core layer in the laminate is formed in a ridge-like stripe structure (hereinafter, referred to as a “ridge channel”). For example, regarding the above-described optical waveguide in which the lower cladding layer, the core layer, the upper cladding layer, and the ohmic contact layer are sequentially stacked, a ridge stripe waveguide is formed by forming a channel from the upper cladding layer and the ohmic contact layer. Is realized. In such a ridge stripe waveguide, it is possible to cause a refractive index change in the core layer below the ridge channel by applying power, and light confinement in the core layer is realized by such a refractive index change.

In general, a ridge stripe waveguide requires a smaller number of crystal growths than a buried stripe waveguide such as a buried-hetero (BH) structure, and can easily provide a waveguide structure. Can be formed. Further, the ridge stripe waveguide is relatively easy to reduce the electric capacity. Therefore,
Waveguide type optical device with ridge stripe waveguide
It is called "ridge waveguide type optical device". ) Is very suitable when low-cost and high-speed operation is required.

[0007]

However, various problems remain in the conventional waveguide type optical element from the viewpoint of improving the yield. That is, in the cleavage step for forming the optical input / output end face of the optical waveguide, a particularly large stress is applied to the vicinity of the cleavage position on the semiconductor substrate. Therefore, a member that does not have a crystal orientation substantially the same as the optical waveguide, for example, a passivation film for protecting the optical waveguide from electrical influences from the outside, a polyimide used for shaping the wafer surface, or a power application. Chipping or peeling of the electrode or the like is likely to occur. In the cleavage step, when the substrate fixing sheet comes into contact with the corner between the wafer surface and the cleavage plane, the substrate fixing sheet sandwiching the wafer may be cut off.

[0008] In this manner, when chipping or peeling of the member or scraping of the substrate fixing sheet occurs, unnecessary small pieces are generated. If such a small piece adheres to the input / output end face of the optical waveguide or the element end face in the vicinity thereof, the reflection of the input / output light to the optical waveguide and
Scattering may be caused, deposition of the film on the portion where the small pieces are attached may not be possible, or the end face coating applied to the cleavage plane may be non-uniform.

In addition, since the polishing process of the back surface of the wafer is generally performed in a state where the back surface is exposed by bonding the front surface of the wafer to a polishing jig, the upper surface of the electrode on the upper surface of the optical waveguide which is the uppermost surface of the wafer surface is polished. Contact As a result, stress is concentrated on the laminate itself, and there is a possibility that a scratch or a defect (for example, distortion) may occur inside the optical waveguide. This is a particularly serious problem in a ridge waveguide type optical device in which stress is easily applied to the optical waveguide due to its structure.

Further, a cleavage surface of the bar wafer is usually coated with a film having a predetermined reflectance and transmittance, for example, a dielectric film. At the time of such film coating, it is necessary to prevent film deposition on the electrode in order to prevent conduction failure of the electrode. Usually, the cleavage surface is covered so as to cover portions other than the cleavage surface (the upper and lower surfaces of the bar wafer). Only the bar is exposed and the bar wafer is fixed to the jig. However, in particular, in the bar wafer on which the ridge stripe waveguide is formed, since the upper surface of the electrode protruding from the wafer surface comes into direct contact with the jig, a direct stress is applied to the ridge stripe waveguide. This stress may damage the electrodes on the wafer surface above the optical waveguide or crack the inside of the optical waveguide.

Furthermore, when the waveguide type optical device is mounted on a carrier for wire bonding to the electrode on the back surface of the device after the chips are finally separated into individual chips, the waveguide type optical device is vacuum-adsorbed collet. Suction the surface of the optical element,
The back surface of the waveguide type optical element is pressed against the carrier. Also in this case, a stress is directly applied to the upper surface of the ridge stripe waveguide projecting in a convex shape, and there is a possibility that an electrode provided on the element surface is damaged or a crack is formed in the optical waveguide.

The present invention has been made in view of the above problems of the conventional waveguide type optical element, and realizes an improvement in yield and a reduction in initial cost by suppressing the generation of fragments and small pieces generated during cleavage. It is an object of the present invention to provide a new and improved waveguide type optical device. It is another object of the present invention to provide a new and improved waveguide type optical device in which the yield is improved by protecting the optical waveguide from stress. Still another object of the present invention is to provide a new and improved waveguide-type optical device in which the device end surface is protected and a plurality of devices can be collectively coated with a uniform end surface.

[0013]

In order to solve the problems of the conventional waveguide type optical device, the invention according to the first aspect of the present invention provides an optical waveguide having an optical input / output end face formed with an optical input / output end face. An end face region that does not have the substantially same crystal direction as the light input / output end face adopts a configuration set back with respect to other end face areas.

According to the first aspect of the present invention, there is provided only an end face region having substantially the same crystal orientation as the light input / output end face on the same plane as the light input / output end face of the optical waveguide. . Therefore, at the time of cleaving the wafer on which the optical waveguide is formed into bars or chips, chipping or peeling of the end face region is prevented, and generation of fragments and small pieces is suppressed. As a result, according to the first aspect of the present invention, the physical and functional damage of the light input / output end face due to the adhesion of the unnecessary substance generated at the time of cleaving the wafer is reduced, and the yield of the waveguide type optical device is greatly increased. Be improved.

According to the first aspect of the present invention, the set-back of the end face region is performed, for example, by forming the set back end face region from a photosensitive material and irradiating the wafer surface with light before cleavage beforehand. This can be done by removing the material. Needless to say, the setback of the end face region can also be realized by various types of wet etching, dry etching, and the like.

According to a second aspect of the present invention, an electrode provided on the upper surface of the optical waveguide and a region other than the upper surface of the optical waveguide are provided on the element surface on which the upper surface of the optical waveguide is formed. By adopting a configuration in which a protective bumper having a surface higher than the above-mentioned electrode is provided, the above-mentioned problem of the conventional waveguide type optical element is solved.

In general, in a waveguide type optical device driven by supplying power, an electrode is formed on the upper surface of the optical waveguide in order to effectively apply power to the optical waveguide. Therefore, there is a high possibility that the optical waveguide will be damaged if stress is applied to the electrode. On the other hand, at the time of manufacturing a waveguide type optical element, various processes such as polishing and fixing of other members are performed on the back surface of the device, and a film is formed on an end surface of the device formed by cleavage. For this reason, when manufacturing a waveguide-type optical device,
It is necessary to directly contact the element surface on which the upper surface of the optical waveguide is formed with, for example, a jig or a substrate fixing sheet.

According to the second aspect of the present invention, when the element surface needs to be brought into contact with, for example, a polishing jig, an element mounting carrier, a substrate fixing sheet, or the like, the protective bumper functions as a spacer, so that the protective bumper functions as a spacer. No stress is applied to the arranged electrodes. Therefore, the optical waveguide is hardly damaged by the stress, and the yield of the waveguide device can be improved. That is, according to the second aspect of the present invention, the yield in the production of the waveguide type optical element is improved from a different viewpoint from the first aspect of the invention, and the initial state of the waveguide type optical element is improved. Cost reduction becomes possible.

According to a third aspect of the present invention, in order to solve the above-mentioned problems of the conventional waveguide type optical element, the optical waveguide has a light input / output end face formed on the element end face protruding from the element end face. A configuration in which a protective bumper is formed is employed. In the third aspect of the invention having such a configuration, the protective bumper prevents contact between the light input / output end face and an external optical element or the like. According to the third aspect of the present invention, the positioning of the waveguide type optical element is performed by using the protective bumper such that the respective optical input / output end faces are arranged on substantially the same plane. Becomes possible.

Therefore, according to the third aspect of the present invention, it is possible to collectively coat the optical input / output end face with a plurality of elements and reduce damage to the optical input / output end face. Can be. That is, by suppressing the damage of the optical input / output end face, the yield of the waveguide-type optical element is increased, and the cost can be reduced by mass-producing the waveguide-type optical element.

It is preferable that the protective bumper according to claim 2 or 3 is made of polyimide, for example, as in the invention of claim 4. In the waveguide type optical device, polyimide can be used for flattening the device surface. According to the invention described in claim 4, it is possible to form a protective bumper without increasing the number of manufacturing steps. As a result, an inexpensive waveguide type optical element with high production efficiency can be easily provided.

Also, in the present invention, it is preferable that the optical waveguide is a ridge-type stripe waveguide, as in the fifth aspect of the present invention. As described above, the ridge-type stripe waveguide can easily form a waveguide structure with a relatively small number of crystal growths, and furthermore, it is relatively easy to reduce the electric capacity of the device. Therefore, according to the fifth aspect of the present invention, it is possible to provide a waveguide type optical element having high operation performance and high manufacturing efficiency.

According to the present invention, the optical waveguide has a first clad layer, a light-transmitting core layer, and a second clad layer laminated in this order. The present invention can be applied to a configuration having a stacked structure. Further, the present invention can be naturally applied to a configuration in which the first cladding layer and the second cladding layer are formed of complementary semiconductors. it can. In such a configuration, for example, an electric field can be applied to the core layer by applying a voltage in the reverse bias direction, or a current can be injected into the core layer by applying a voltage in the forward bias direction.

In order to solve the above-mentioned problem, the invention according to claim 8 is a method for preparing a cleavage, in which, at a predetermined position on a wafer, a member not having the same crystal orientation as the optical waveguide is removed in advance. A method for manufacturing a waveguide-type optical device, comprising: a step of cleaving a wafer by cleaving at a predetermined position.

[0025] In the cleavage step of the invention according to the eighth aspect of the present invention, the crystal direction is aligned in the divided portion of the wafer, and ideal cleavage is possible. Therefore, fine fragments generated by chipping or peeling of the member are reduced. As a result, in the invention according to the eighth aspect, the risk of unnecessary substances adhering to the optical input / output end face is reduced, and the yield of the manufactured waveguide type optical element is improved.

According to a ninth aspect of the present invention, an electrode is formed on an upper surface of an optical waveguide on an element surface of a waveguide type optical element on which the upper surface of the optical waveguide is formed. Provided is a method for manufacturing a waveguide-type optical device, comprising: an electrode forming step; and a surface protective bumper forming step of forming a protective bumper having a surface higher than the electrode on a portion of the element surface other than the upper surface of the optical waveguide. .

As described above, when a waveguide type optical device is manufactured, it may be necessary to bring the surface of the device into contact with the fixing means when processing the back surface of the device. In such a case, in the ninth aspect of the present invention, since the protective bumper serves as a spacer between the element surface and the fixing means, the electrode formed on the optical waveguide does not contact the fixing means. Therefore,
According to the ninth aspect of the present invention, the stress applied to the optical waveguide is reduced, and the possibility of damage inside the optical waveguide is reduced.

Further, in order to solve the above problems,
According to a tenth aspect of the present invention, there is provided an end face protection bumper forming step of forming a protection bumper on an element end face of a waveguide type optical element in which an optical input / output end face of an optical waveguide is formed, and a waveguide using the protection bumper. A method for manufacturing a waveguide-type optical element, comprising: aligning the optical element and forming a film on the end face of the element.

The invention according to claim 10 having such a configuration is as follows.
Since the protection bumper prevents the contact between the light input / output end face and the external device, the yield of the waveguide type optical element can be improved. Further, in the invention according to claim 10,
It is possible to perform uniform film coating on the cleavage planes of a plurality of bar wafers collectively. Therefore, according to the tenth aspect of the present invention, it is possible to improve the production efficiency of the waveguide-type optical device and to provide a low-cost waveguide-type optical device.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments when the present invention is applied to an optical functional device will be described below in detail with reference to the accompanying drawings. In the following description and the accompanying drawings, components having substantially the same functions and configurations are denoted by the same reference numerals, and redundant description will be omitted. In addition, coordinates indicating directions are defined in each attached drawing, and these coordinates are for clarifying the direction of each drawing. In the following, an embodiment of the present invention will be described using such coordinates as appropriate.

(First Embodiment) First, the first embodiment of the present invention will be described.
The embodiment will be described with reference to FIGS. FIG. 1 is a sketch drawing showing a schematic configuration of the optical functional device 100 according to the present embodiment, and FIGS.
FIGS. 4A to 4C are explanatory diagrams for each manufacturing process of the optical functional element 100. FIGS.

As shown in FIG. 1, the optical functional device 100 according to the present embodiment is a one-chip optical device mainly composed of an n-InP-based semiconductor. Such an optical functional device 1
00, two cleaved end faces substantially parallel to the XZ plane and facing each other, that is, a first element end face 100a and a second element end face 1
00b, and a ridge-type optical waveguide 100c extending in the Y direction over the first element end face 100a and the second element end face 100b.

The steps of manufacturing the optical functional device 100 having such a configuration will be described in order. The first step is Figure 2.
This is a lamination step shown in FIG. In this step, for example, n-
The wafer 10 is formed by sequentially laminating the lower clad layer 120, the light guide layer 130, the upper clad layer 140, and the contact layer 150 on the conductive type substrate 110 made of InP in the Z direction.

To describe this step in more detail, first, for example, an n-InP layer is grown on the upper surface of the substrate 110 by epitaxial growth or the like to form the lower cladding layer 120 of the conductivity type. Next, the lower cladding layer 12
An optical guide layer 130 is formed by growing, for example, an undoped InGaAsP layer on the upper surface of the substrate 0 by epitaxial growth or the like. Further, for example, a p-InP layer is grown on the upper surface of the light guide layer 130 by epitaxial growth or the like to form a conductive type upper cladding layer 140.
Furthermore, for example, p
^{A +} -InGaAs layer is grown to form a conductive contact layer 150. In the wafer 10 formed in this step, a structure in which the light guide layer 130 is sandwiched between the lower clad layer 120 and the upper clad layer 140 is formed. Direction), light can be confined in the core layer.

The second step is a waveguide structure forming step shown in FIG. In this step, the mesa 160 extending in the Y-direction is formed by etching the upper surface of the wafer 10 at a predetermined interval. More specifically, first, a substance for an etching mask, for example, a dielectric is deposited on the upper surface of the contact layer 150, and then the formed dielectric film is left in a stripe shape by, for example, photolithography. Next, the surface of the wafer 10 is etched to the depth of the upper surface of the light guide layer 130 using the dielectric film left in a stripe shape as a mask, thereby forming a mesa 160. The mesa 160 includes an upper cladding layer 140 and a contact layer 150 extending like a strip in the Y direction.

In the wafer 10, by forming the mesas 160 as described above, light confinement in the X direction (lateral direction) in the light guide layer 130 located below the mesas 160 becomes possible. A ridge-shaped optical waveguide 100c having the optical guide layer 130 as a core is formed.

The mesa 160 formed in this step is
For example, the width can be about 4 μm. In this step, a double channel structure 160a, which is a groove dug by etching, is formed on each side of the mesa 160, and the double channel structure 160a can have a width of, for example, about 10 μm. Further, this step can be performed by various wet etching and dry etching.

The third step is the embedding step shown in FIG. In this step, the buried layer 100d is formed in the double channel structure 160a formed on both sides of the mesa 160 in the waveguide structure forming step shown in FIG. More specifically, first, the upper surface of the wafer 10 on which the mesas 160 are formed is coated with an electrically insulating material, for example, a dielectric, and a passivation film 170 is formed. The optical waveguide 100 is formed by the passivation film 170.
The light guide layer 130 of c is electrically protected from the outside.

In this step, the passivation film 1
The upper surface of the wafer 10 coated with 70 is planarized by, for example, photosensitive polyimide 180. Such flattening is performed by, for example, spin coating or the like on the wafer 1.
This is realized by applying polyimide 180 on the upper surface. As a result, the double channel structure 160a is buried with the polyimide 180, and buried layers 100d are formed on both sides of the mesa 160.

In the fourth step, the first electrode 15 shown in FIG.
0a (p side). In this step, first, the polyimide 180 and the passivation film 170 attached to the optical waveguide 100c are removed, and the upper surface of the contact layer 150 of the mesa 160 corresponding to the electrode formation surface is exposed.
Next, a conductive material is deposited on the entire surface of the wafer 10,
The first electrode 150a is formed. In the optical waveguide 100c, power can be supplied to the upper cladding layer 140 via the contact layer 150 by forming the first electrode 150a.

In the fifth step, the second electrode 11 shown in FIG.
0a (n side). In this process, the wafer 1
By polishing the back surface (lower surface) of the substrate 110 to a predetermined thickness, the second electrode 110a for bonding is formed on the entire back surface of the substrate 110. In the optical waveguide 100c, power can be supplied to the lower cladding layer 120 via the substrate 110 by forming the second electrode 110a. As a result, in the optical waveguide 100c, a physical parameter such as an electric field, a magnetic field, or a temperature can be changed in the optical guide layer 130 by current injection or application of an electric field, and a predetermined optical processing function is realized. Is done.

The sixth step is a cleavage preparation step according to the present embodiment shown in FIGS. In this step, first, as shown in FIG. 7, a surface 100e substantially parallel to the XZ plane is set at a predetermined interval as a position where the wafer 10 is cleaved. Further, a predetermined width sandwiching the surface 100e, for example, several μm
A region having a width of m to several tens μm (hereinafter, referred to as a “cleavage region”).
190 is set. Then, on the surface of the electrode 150a between the adjacent cleavage regions 190, the optical waveguide 1
A convex etching mask M that covers 00c and protrudes in the X direction at an intermediate portion between adjacent cleavage planes 190 is formed.

In this step, next, as shown in FIG. 8, the first electrode 150a and the polyimide 180 are etched on the wafer 10 on which the etching mask M is formed.
And the passivation film 170 are removed. As a result, the first electrode 150a remains in a convex shape as viewed from the Z direction so as to cover the optical waveguide 100c between the cleavage regions 190. In the following, the first electrode 150 having a convex shape is used.
The part protruding in the X direction of the bonding part 150b
That.

In this step, next, as shown in FIG. 9, the buried layer 100d in the cleavage region 190 is removed by a predetermined method, for example, by irradiating the surface of the wafer 10 with light. By the cleavage preparation step according to the present embodiment described above, the first electrode 150
a and the buried layer 160 (made up of the passivation film 170 and the polyimide 180) are removed.

The seventh step is a step of cleaving the wafer 10 shown in FIGS. As shown in FIG. 10, in this step, the wafer 10 is sandwiched between the first electrode 150a side and the second electrode 110a side by the substrate fixing sheet S,
Forces F and F 'in the Z direction are applied to both sides of the surface 100e in the Y direction. By applying the force F to the wafer 10 in this manner, stress concentrates on the cleavage plane 100f on the plane 100e,
The cleavage of the wafer 10 is performed on the cleavage plane 100f.

As a result, a strip bar wafer 10a extending in the Y direction is cut out from the wafer 10 shown in FIG. In the bar wafer 10a, the optical waveguides 100 are arranged on the cleavage plane 100f at predetermined intervals in the X direction.
Although the end face of the optical waveguide 100c is exposed, the end face of the optical waveguide 100c becomes the light input / output end face of the optical waveguide 100c.

In this embodiment, the buried layer 100d in the cleavage region 190 and the first electrode 150a are removed from the wafer 10 in the cleavage preparation step described with reference to FIGS. Therefore, in the cleavage step shown in FIGS. 10 and 11, the first electrode 15
0a and the buried layer 160 are set back, and the crystal directions of the wafer 10 on the cleavage plane 100f are substantially aligned. As a result, the wafer 10 has a cleavage plane 10f.
It can be seen that it is cleaved neatly.

Here, a verification experiment performed by the inventor on the present embodiment will be described. In this verification experiment, the inventor cleaved the wafer on which the ridge waveguide was formed, and manufactured a ridge waveguide type optical modulator bar wafer having the same basic configuration as the bar wafer 10a. When the inventors observed both end faces of the ridge waveguide formed on the cleavage plane of the manufactured optical modulator bar wafer, it was confirmed that the electrodes, the passivation film, and the small pieces of polyimide hardly adhered. Was. In this verification experiment, the set width of the cleavage region is 20 μm.

Returning to the description of the manufacturing process of the optical functional device 100, the eighth process after the cleavage shown in FIG.
1 and a chip forming step shown in FIG. As shown in FIG. 11, in this step, first, a predetermined end face coating according to a use is applied to the cleavage plane 100f, and a first element end face 100a and a second element end face 100b are formed from the cleavage plane 100f. Next, near the middle of the adjacent optical waveguide 100c,
The bar wafer 10a is cut at a cutting plane A substantially parallel to the YZ plane. As a result, the one-chip optical function element 100 shown in FIG. 1 is formed.

Next, the operation of the optical functional device 100 according to the present embodiment formed as described above will be described with reference to FIG. In the optical function device 100, the first
Light L incident from the element end face 100a is input to the light guide layer 130 from the end face of the optical waveguide 100c formed on the first element end face 100a.

In the optical function device 100, the first electrode 150a
By applying a predetermined bias voltage between the first electrode 110a and the second electrode 110a, a predetermined light processing function for confining light to the light guide layer 130 and for propagating light below the mesa 160 extending in the Y direction is realized. You. At the same time, the first
When an electric signal is applied between the electrode 150a and the second electrode 110a, a change corresponding to the electric signal occurs below the mesa 160 extending in the Y direction.

Accordingly, the light L is optically processed by the light guide layer 130 in the optical waveguide 110c, and is output from the end face of the optical waveguide 100c formed on the second element end face 110b. Needless to say, the second element end face 10
When the light L is incident from the side of the optical waveguide 1b, the light L
Similarly, the optical waveguide 10 formed on the first element end face 110a is processed by the light guide layer 130 in the optical waveguide 10c.
0c is output from the end face.

In the present embodiment described above, by providing a cleavage region near the element end face located in the direction of travel of the optical waveguide, an electrode, a passivation film, or a fragment or a small piece of polyimide or the like when cleaving the wafer is provided. Is suppressed. Therefore, according to the present embodiment, in the waveguide type optical element, there is a great possibility that an unnecessary substance adheres to the optical input / output end face formed on the cleavage plane or the optical input / output end face is damaged by the unnecessary substance. To be reduced. As a result, according to the present embodiment, the yield in the cleavage step of the waveguide optical device can be greatly improved.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
The embodiment will be described mainly with reference to FIG. 12 and FIG. FIG. 12 is a sketch drawing showing a schematic configuration of the optical functional device 200 according to the present embodiment.
FIG. 13 is an explanatory diagram of one effect of the optical function element 200.

As shown in FIG. 12, the optical functional device 200 according to the present embodiment has substantially the same basic configuration as the optical functional device 100 according to the first embodiment shown in FIG. . However, the optical function device 20 according to the present embodiment
0 is the element surface 200a on which the first electrode 150a is formed.
In addition, a surface protection pad 290 is further formed, which is different from the optical functional element 100 according to the first embodiment shown in FIG.

Surface protection pad 29 according to the present embodiment
0 are formed on the element surface 200a on the outer edge side of the buried layer 100d, two on each side of the optical waveguide 100c. One of the two surface protection pads 290 formed on one side is disposed on the first element end face 110a side, and the other is disposed on the second element end face 110b side.

The surface protection pad 290 is formed so as to be higher than the first electrode 150a above the optical waveguide 100c, that is, to protrude most in the Z direction on the element surface 200a. The surface protection pad 290 is, for example, several tens of μm square and has a thickness of about 2 μm.
m.

Further, the surface protection pad 290 is
In the embedding process shown in FIG. 4, a polyimide 180 is formed on the surface of the wafer 10 thicker than the first electrode 150a shown in FIG. 5, and in the cleavage preparation process shown in FIGS.
It can be formed by leaving the polyimide 180 attached to a predetermined position without removing it.

The optical functional element 200 according to the present embodiment having the above-described features exerts its effect in, for example, the step of coating the end face of the bar wafer 10a shown in FIG. Note that the step of coating the end face of the bar wafer 10a shown in FIG. 13 is included in the chip forming step described with reference to FIG. 11 in the first embodiment.

In this step, the bar wafer 10a is moved to the first electrode 150a side by the jig J so that a film to be coated on the cleavage plane 100f does not adhere and the first electrode 150a or the second electrode 110a does not cause conduction failure. It is sandwiched from the second electrode 110a side. At this time, in the configuration according to the present embodiment, since the protective bumper 290 functions as a spacer between the jig J and the surface of the bar wafer 10a,
The portion of the first electrode 150a located above the optical waveguide 100c does not contact the jig J, and no stress is applied to the optical waveguide 100c.

Further, even when the surface of the wafer 10 needs to be fixed to a jig by the operation of the surface protection pad 290 as in the step of forming the second electrode 110a shown in FIG.
The first electrode 150a does not directly contact the jig. Also, FIG.
In the case where a metal wire (not shown) is bonded to the second electrode 110a after the bar wafer 10a shown in FIG. 1 is separated and chipped, the first electrode 150a formed on the optical waveguide 100c is mounted on a mounting carrier (not shown). There is no contact.

Here, a verification experiment performed by the inventor on the present embodiment will be described. The waveguide type optical device manufactured by the inventor for this verification experiment has a surface electrode and a polyimide pad on the device surface. In the waveguide type optical device manufactured by the inventor, the surface electrode corresponds to the first electrode 150a shown in FIG.
It has a convex shape when viewed from the element surface side corresponding to the direction.
A portion (hereinafter, referred to as a “convex portion”) protruding from the double channel of the surface electrode to a region closer to the outer edge of the element surface corresponds to the bonding portion 150b shown in FIG. In the waveguide type optical device manufactured by the inventor,
The polyimide pad is a surface protection pad 29 shown in FIG.
It corresponds to 0.

In such a waveguide type optical device manufactured for this verification experiment, the convex portion of the surface electrode and the polyimide pad become components corresponding to the protective bumper on the device surface, and the device surface, the fixing means, and the like. Serves as a spacer between them. That is, the projections of the surface electrode and the polyimide pad prevent the upper surface of the ridge stripe waveguide from directly contacting the jig when the bar wafer before chipping into a waveguide type optical element is fixed to the jig.

According to the results of observation by the inventor of the bar wafer removed from the jig after the end face coating, traces of contact with the jig remain firmly on the convex portion of the surface electrode and the polyimide pad, and the ridge stripe of the surface electrode is removed. It was confirmed that almost no residue was left on the portion located on the upper surface of the waveguide. The inventor fixed the device surface of the manufactured waveguide type optical device to a jig and polished the device back surface. In such a case, similarly, in such a case, the device was located on the upper surface of the ridge stripe waveguide of the surface electrode. No trace of contact with the jig was observed on the part.

Further, in order to perform wire bonding to the back electrode (corresponding to the second electrode 110a shown in FIG. 12) of the manufactured waveguide type optical element, the inventor suctions the element surface with a vacuum suction collet. And mounted a waveguide type optical element on a carrier. In this case as well, traces of contact were observed between the protrusions of the surface electrode before and after handling the chip sucked by the vacuum collet and the polyimide pad, but the vacuum was not applied to the portion of the surface electrode located on the upper surface of the ridge stripe waveguide. No trace of contact with the adsorption collet was observed. That is, also in this case, it was confirmed that the convex portion of the surface electrode and the polyimide pad functioned as a spacer.

As described above, according to the present embodiment, the polishing step and the end face coating can be performed without applying stress to the ridge type optical waveguide itself by the protective pad and the bonding portion corresponding to the protective bumper on the element surface. A process or an assembly process (a process of attaching / detaching / transferring chips during chip bonding) can be performed. In particular, the provision of the protection pad has a great effect in protecting the ridge waveguide far away from the bonding portion.

(Third Embodiment) Next, a third embodiment of the present invention will be described.
The embodiment will be described mainly with reference to FIG. 14 and FIG. FIG. 14 is a sketch drawing showing a schematic configuration of the optical functional device 300 according to the present embodiment.
FIG. 15 is an explanatory diagram of one effect of the optical function element 300.

As shown in FIG. 14, the optical functional device 300 according to the present embodiment has substantially the same basic configuration as the optical functional device 100 according to the first embodiment shown in FIG. . However, the optical function device 30 according to the present embodiment
No. 0 is provided with an end surface protection pad 390 on each of the first element end surface 110a and the second element end surface 110b.
This point is different from the optical functional device 100 according to the first embodiment shown in FIG.

The end surface protection pad 390 provided on the first element end face 100a is in direct contact with the element surface 300a on which the first electrode 150a is formed, and the first element end face 10a.
0a is formed so as to protrude in the Y direction. End face protection pad 3 provided on one second element end face 100b
90 is also formed in the same manner as the end face protection pad 390 provided on the first element end face 100a.

The end surface protection pad 39 according to the present embodiment
For example, in the cleavage preparation process shown in FIGS. 7 to 9, the polyimide layer 1 is left without removing the buried layer 100 d at the position where the end surface protection pad 390 is formed.
80. That is, since polyimide generally has poor adhesion to a semiconductor material, in the cleaving step of the wafer 10 shown in FIG. 9, the remaining polyimide 180 of the cleavage region 190 is cut at the cleavage plane 100f by the bar wafer 10a (see FIG. 9). 11).

In this cleavage step, polyimide 18
Which of the bar wafers 10a is in close contact with 0 depends on which of the bar wafers 10a the polyimide 180 has straddled. That is, in the preliminary cleavage process shown in FIGS. 7 to 9, when the buried layer 100d in the cleavage region 190 is removed, the polyimide 180 is left asymmetrically with respect to the surface 100e.
It is possible to control which bar wafer 10a 0 is in close contact with.

Note that reference numeral 3 shown by a dotted line in FIG.
Reference numeral 90 ′ denotes a protective bumper that is in close contact with another optical function element 300 adjacent to the bar wafer 10a when the end face protective pad is formed from the polyimide 180 as described above. The dimensions of the end face protection pad are, for example, several tens of μm square and about 2 μm in thickness.

Optical function element 300 according to this embodiment
Has the above-described configuration, and thus exhibits its effect in the end face coating step shown in FIG.
The end face coating step shown in FIG.
This is a manufacturing process included in the chip forming step described with reference to FIG. 11 in the embodiment, and in this step, the bar wafer 1 before the optical function elements 300 are individually chipped.
0a is coated with an end face.

As shown in FIG. 15, first, since the end face protection pad 390 protrudes from the cleavage plane 100f, when the bar wafer 10a is fixed to the jig J, the optical waveguide 1
The cleavage face 100f exposing the end face of 00c is prevented from directly contacting the positioning jig P. Furthermore, the end face protection pad 3
By using the position 90, each cleaved surface 10
The plurality of bar wafers 10a can be fixed to the jig J such that 0f is substantially on the same plane.

The optical function device 3 according to the present embodiment
No. 00 indicates that the angle between the surface of the wafer 10 and the cleavage plane 100f (having an angle of about 90 °) does not come into contact with the substrate fixing sheet S in the cleavage step of the wafer 10 shown in FIG. Edge protection pad 3 with smooth curved surface
Contact 90. Therefore, the adhesion of the substrate fixing sheet S to the cleavage plane 100f is removed or reduced.

As described above, according to the present embodiment, the risk of damaging the light input / output end face of the ridge waveguide is reduced at the time of manufacturing the waveguide type optical element, particularly in the step of coating the end face on the cleavage plane. . Furthermore, in the end face coating step, the end faces can be collectively coated on a plurality of bar wafers by using the protective pads for positioning. Furthermore, according to the present embodiment, in the step of cleaving the wafer, the attachment of the substrate fixing sheet to the cleaved end face is removed or reduced. That is, according to the present embodiment, it is possible to mass-produce the waveguide-type optical device with a high yield, so that the initial cost of the waveguide-type optical device can be reduced by improving the productivity.

Although the preferred embodiments of the present invention have been described with reference to the accompanying drawings, the present invention is not limited to such configurations. Within the scope of the technical idea described in the appended claims, those skilled in the art will be able to conceive various changes and modifications, and those changes and modifications are also within the technical scope of the present invention. It is understood that it belongs to.

For example, in the above-described embodiments, the waveguide type optical element has been described by exemplifying the composition, dimensions and the like of each constituent member, but the present invention is not limited to such a configuration. The present invention can also be applied to a waveguide type optical device composed of components having various other compositions and dimensions.

In the above embodiment, the waveguide type optical element in which the surface protection pad and the end face protection pad are continuously formed from polyimide used for shaping the wafer surface has been described as an example. Is not limited to such a configuration. The present invention can be applied to a waveguide type optical device having various other surface protection pads and edge protection pads.

Further, in the above embodiment, the waveguide type optical element having the surface protection pad formed thereon and the waveguide type optical element having the end face protection pad separately illustrated and described, but the present invention has such a configuration. It is not limited to. The present invention can also be applied to a waveguide type optical element in which a bumper having both the function of a surface protection pad and the function of an end face protection pad is formed on the outer edge of the element surface.

Further, in the above embodiment, the optical modulator is exemplified as the waveguide type optical element, but the present invention is not limited to this configuration. The present invention provides various other waveguide type optical devices such as a semiconductor laser, an optical amplifier, a wavelength converter, a wavelength filter, a mode converter or an LED, or a suitable combination thereof on the same substrate. The present invention can also be applied to integrated elements and the like.

Further, in the above-described embodiment, the ridge waveguide type optical element has been described as a preferred embodiment in view of the effect, but the present invention is not limited to this configuration. The present invention can be applied to other various channel waveguide optical devices, for example, a BH waveguide optical device, a mesa stripe, and the like, or various planar waveguide optical devices.

[0083]

According to the present invention, the generation of unnecessary objects in the cleavage step and the like is suppressed without significantly changing the conventional manufacturing method, and the mechanical and functional obstacles generated on the optical input / output end face of the optical waveguide are reduced. Can be reduced. According to the present invention,
By suppressing the stress applied to the optical waveguide, it is also possible to reduce mechanical damage to the optical waveguide. further,
According to the present invention, batch processing of the waveguide type optical element can be performed. Therefore, by applying the present invention, it is possible to easily improve the yield of the waveguide-type optical device, and as a result, the cost of the waveguide-type optical device can be reduced by improving the production efficiency.

[Brief description of the drawings]

FIG. 1 is a sketch drawing showing a schematic configuration of an optical functional device applicable to the present invention.

FIG. 2 is an explanatory view illustrating one manufacturing process of the optical functional device shown in FIG.

FIG. 3 is an explanatory diagram of another manufacturing process of the optical functional device shown in FIG.

FIG. 4 is an explanatory diagram of another manufacturing process of the optical functional device shown in FIG.

FIG. 5 is an explanatory diagram illustrating another manufacturing process of the optical functional device illustrated in FIG. 1;

FIG. 6 is an explanatory diagram illustrating another manufacturing process of the optical functional device illustrated in FIG. 1;

FIG. 7 is an explanatory diagram illustrating another manufacturing process of the optical functional device illustrated in FIG. 1;

FIG. 8 is another explanatory view of the manufacturing process shown in FIG. 7;

FIG. 9 is another explanatory view of the manufacturing process shown in FIG. 7;

FIG. 10 is an explanatory diagram illustrating another manufacturing process of the optical functional device illustrated in FIG. 1;

FIG. 11 is an explanatory diagram illustrating another manufacturing process of the optical functional device illustrated in FIG. 1;

FIG. 12 is a sketch drawing showing a schematic configuration of another optical functional element to which the present invention can be applied.

13 is an explanatory diagram of an effect of the optical functional device shown in FIG.

FIG. 14 is a sketch drawing showing a schematic configuration of another optical function element according to the present invention.

15 is an explanatory diagram of an effect of the optical function device shown in FIG.

[Explanation of symbols]

 100, 200, 300 Optical functional elements 100a, 100b Device end face 100c Optical waveguide 100e surface 120 Lower cladding layer 130 Optical guide layer 140 Upper cladding layer 150a Bonding portion 150b First electrode 190 Cleaved region 290, 390 Protection pad

Claims (10)

[Claims] 1. A waveguide type optical element having an optical waveguide formed therein, wherein an optical input / output end face of the optical waveguide is formed at an element end face having substantially the same crystal orientation as the optical input / output end face. A waveguide type optical device, wherein an end face region not provided is set back with respect to another end face area. 2. An optical waveguide device having an optical waveguide formed thereon, wherein an electrode provided on the electrode formed surface of the optical waveguide is provided on an element surface on which the electrode formed surface of the optical waveguide is formed. A waveguide type optical device, comprising: a protective bumper having a surface higher than the electrode provided in a region other than the upper surface of the optical waveguide. 3. A waveguide type optical device having an optical waveguide formed thereon; a protection bumper protruding from the device end surface is formed on an element end surface of the optical waveguide on which an optical input / output end surface is formed. A waveguide-type optical element, characterized in that: 4. The waveguide type optical device according to claim 2, wherein said protection bumper is formed of polyimide. 5. The waveguide type optical device according to claim 1, wherein said optical waveguide is a ridge type stripe waveguide. 6. The optical waveguide according to claim 1, wherein the optical waveguide has a laminated structure in which a first clad layer, a core layer for transmitting light, and a second clad layer are sequentially laminated. ,
6. The optical waveguide device according to any one of 2, 3, 4, and 5. 7. The semiconductor device according to claim 1, wherein said first cladding layer and said second cladding layer are formed of complementary semiconductors. A waveguide optical device according to any one of the above. 8. A method for manufacturing a waveguide-type optical device, comprising: manufacturing a waveguide-type optical device by dividing a wafer on which an optical waveguide is formed at a predetermined position so that the optical waveguide is divided;
A cleaving preparation step of previously removing a member having no crystal orientation substantially the same as that of the optical waveguide at the predetermined position of the wafer, and dividing the wafer by cleaving at the predetermined position; And a step of manufacturing the waveguide-type optical element. 9. A method for manufacturing a waveguide-type optical device having an optical waveguide formed thereon, wherein an electrode is provided on the upper surface of the optical waveguide on the device surface of the waveguide-type optical device on which the upper surface of the optical waveguide is formed. Forming a protective bumper having a surface higher than the electrode on a part of the element surface other than the upper surface of the optical waveguide. To manufacture a waveguide type optical element. 10. A method of manufacturing a waveguide-type optical device having an optical waveguide formed thereon, wherein the optical waveguide has a light-in / out end surface formed on the device-end surface of the waveguide-type optical device, and protrudes from the element surface. Forming an end face protection bumper, and forming an end face film on the element end face by using the protection bumper to align the waveguide type optical element. A method for manufacturing a waveguide-type optical element, characterized by comprising: