JP4359493B2 - Optical waveguide component and manufacturing method thereof - Google Patents

Description

  The present invention relates to an optical waveguide component used for optical signal level adjustment and switching, and can be applied to, for example, an optical communication system.

  A variable optical attenuator that adjusts the level of an optical signal and an optical switch that switches an optical signal path are indispensable optical components for realizing an operation of an advanced and flexible optical communication system. Examples of the optical waveguide component include a thermal capillary type optical switch and a variable optical attenuator (see Patent Documents 1 and 2 below). These optical waveguide parts have a structure in which a groove is formed so as to cross the core part that propagates light in the planar optical waveguide, and a refractive index matching liquid having a refractive index equal to the refractive index of the core part is enclosed in the groove. Have

  In these thermocapillary optical devices, a heater provided near the groove gives a local temperature gradient to the liquid sealed in the groove across the core, and the change in surface tension due to the difference in temperature is used to apply the sealed liquid. The principle of moving in the groove is used.

  FIG. 4 is a schematic cross-sectional structure diagram of a conventional optical component using surface tension. As shown in the figure, in the conventional optical component 40 using surface tension, the groove 43 formed so as to cross the core portion 42 of the optical waveguide layer 41 is confined with glass (Pyrex lid 47) and in the vicinity of the groove 43. The position of the refractive index matching liquid 49 in the groove 43 is adjusted by the heater 44 provided in the structure so that an optical switch function and an optical attenuation function are exhibited. “Pyrex” is a registered trademark and is a representative product of borosilicate glass containing boron oxide.

  The groove 43 formed in the optical waveguide layer 41 is an isolated space by a glass lid (Pyrex lid 47), but actually has an extremely small cross section in order to inject the refractive index matching liquid 49 inside. An injection path (not shown) is connected to each groove 43, and the groove 43 is connected to the outside.

  The refractive index matching liquid 49 is injected into the groove 43 by dropping the refractive index matching liquid 49 into the opening of the injection path under reduced pressure and then returning to the atmospheric pressure. If the pressure at the time of depressurization is adjusted based on the amount of gas desired to remain in the groove 43, the necessary amount of refractive index matching liquid 49 can be injected into the plurality of grooves 43 equally and simultaneously. After injecting the refractive index matching liquid 49, a sealant is applied to the opening of the injection path and sealed. Since the cross section of the injection path is extremely small, when the sealant enters and hardens, it is completely sealed with extremely high reliability (see Patent Document 3 below).

  In order to form the sealed structure of the groove 43, it is important to join the glass lid, which is joined using a technique called anodic bonding. A bonding silicon layer 50 is deposited on the surface of the planar optical waveguide, and a Pyrex plate is used for the glass lid. Usually, a planar optical circuit is manufactured by depositing a silica layer having a thickness of several tens of μm on a silicon substrate 48 having a thickness of about 1 mm. Close to a coefficient of thermal expansion of 48. The reason why Pyrex is used for the glass lid to be joined is that the thermal expansion coefficient of Pyrex is close to the thermal expansion coefficient of silicon in a temperature range from room temperature to several hundred degrees of anodic bonding.

  Anodic bonding can be performed with borosilicate glass containing alkali metal ions that are easy to move in the glass, but if the thermal expansion coefficients of the substrate material and the lid material are not fully taken into account, the high temperature state at the time of bonding is changed to the room temperature state. It is destroyed by the stress generated with cooling.

  The temperature is set to 250 ° C. to 500 ° C., a cathode is connected to the Pyrex lid 47 side, an anode is connected to the bonding silicon layer 50 deposited on the surface of the planar optical waveguide, and a voltage of 100 V to 1000 V is applied. It can be fixed in close contact with the planar optical circuit. Anodic bonding is a bonding method that achieves bonding at the atomic level by utilizing the attractiveness between bonding interfaces due to electrostatic attraction. The bonding strength at the bonding interface is close to the fracture strength of the material, and the airtightness is also high. Extremely expensive. Therefore, it is an optimum joining method for the optical component 40 using surface tension that needs to contain the refractive index matching liquid 49 stably for a long period of time.

  As an optical component similar to the optical component 40 using surface tension described above, there is an optical switch provided with a vertical fluid-filled hole manufactured by Agilent Technologies (see Patent Document 4 below). This optical switch is an optical component that uses the principle of generating and maintaining bubbles by heating with a heater and manipulating an optical signal passing through the core of the optical waveguide. This optical switch has a structure in which a silicon substrate provided with a heater and its wiring is joined to the surface of a planar optical waveguide provided with a groove by soldering.

  In the optical switch using surface tension, it is necessary to seal each groove independently. However, in the optical switch manufactured by Agilent Technologies, the grooves for optical switching are connected. It is performed by soldering so as to surround the structure at a place away from. In other words, the part where the groove that becomes the heart of the optical switch is formed is maintained in a state where it is completely immersed in the liquid. In order to realize this state, the groove is formed on the surface using the silicon substrate provided with the heater as a lid. A ring-shaped metal gasket is sandwiched between the formed optical waveguide substrate and a sealed space is formed, and the sealed space is filled with a liquid. At this time, the metal gasket and the silicon substrate as the lid and the optical waveguide substrate are bonded by solder bonding. Since the inner diameter of the metal gasket is large and the groove forming the heart of the optical switch is completely contained in the gasket, the switch structure is sufficiently separated from the bonded portion of the gasket.

JP 2003-121146 A JP-A-8-62645 Japanese Patent Laid-Open No. 10-73775 JP-A-11-271651

  An optical component using a surface tension manufactured using a Pyrex plate as a lid needs to form a heater for driving and wiring for supplying electric power to the heater on the surface of the planar optical waveguide. For this reason, if it is attempted to dispose more than several tens of elements in one optical waveguide circuit, it is difficult to secure an area for wiring. That is, the individual elements that are the elements of the surface tension-based optical component can be arranged within a 150 μm square, so if the area for wiring can be reduced, a very compact optical switch or optical attenuator array can be used. Can be realized.

  However, with the conventional method of wiring on the surface of a planar optical circuit, for example, a device in which a large number of optical switches and optical attenuators are combined in the same optical circuit, or a matrix optical switch having an 8 × 8 scale or more can be made small It was difficult.

  In the case of an 8 × 8 matrix optical switch, for example, considering a design in which two heaters are arranged in one element, it is necessary to drive a total of 128 heaters independently, and even if the GND side is shared, A total of 129 wires are required. In order to arrange this in the gap between the elements, it is necessary to increase the distance between the elements, which increases the size of the entire circuit. As the circuit becomes larger, there is a problem that the manufacturing cost increases.

  On the other hand, it is also possible to adopt a wiring method in which wirings are stacked in two layers, a vertical wiring is provided in the first layer, a horizontal wiring is provided in the second layer, and inserted into the heater at the intersection. It is. According to this wiring method, in the 8 × 8 scale matrix optical switch, the target heater can be driven by a total of 24 wires, with the horizontal wires being GND, but incomplete. Here, the term “incomplete” means that a current flows in addition to the target heater (a sneak current) because the wiring is assembled in a mesh.

  As a method of eliminating this unnecessary sneak current, a method of connecting a rectifier, that is, a diode in series with a heater is effective (see “Optical Switch” in Japanese Patent Laid-Open No. 2001-31888). Furthermore, it is conceivable to further reduce wiring by incorporating a memory circuit (flip-flop circuit) using a thin film transistor used in the manufacture of a liquid crystal display and a heater drive circuit (current switch) for each heater.

  In the 8 × 8 scale matrix optical switch, in addition to the power supply line and the GND line, a minimum of 24 lines are required as a matrix designating line. Here, because the heater drive current flows in the wiring specified in the vertical and horizontal directions of the diode array, wiring corresponding to that is necessary, but in the array using transistors, the matrix specification is a logic circuit, unlike this, Almost no current flows. For this reason, in the transistor array, a polysilicon wiring having a high wiring resistance can be applied, and it is sufficient that the wiring is thin. Of course, it is inevitable that the number of wiring layers is two or more in both the diode array and the transistor array.

  Forming these semiconductor elements in a planar optical circuit seems to be possible at first glance, with some examples of liquid crystal displays, but the driving current of liquid crystal displays is extremely low, less than microamperes, whereas surface tension-based light The heater driving current in the part is several tens of milliamperes. Thus, both devices have a drive current gap of 4 digits or more, and polysilicon or amorphous silicon deposited on the glass surface layer does not have a current capacity that can be realized in a small area of about several hundred micron squares. Therefore, a technique using a thin film transistor cannot be applied to the optical component using surface tension.

  On the other hand, it is relatively easy to manufacture the above-described diode array or transistor array on a silicon substrate by a technique similar to ordinary IC. Furthermore, by simultaneously forming a heater on this, electric wiring for driving the optical component using surface tension can be realized.

  However, it is difficult to closely bond the semiconductor element thus fabricated to the planar optical circuit. For example, a bonding method using a material that fills a gap as a liquid in a space sandwiched between both surfaces, such as an adhesive, molten glass, or solder, fills a fine structure such as a groove or an injection path. Therefore, it cannot be adopted.

  Further, the method of solder joining so as to surround the structure at a position away from the switch structure, which is employed in the manufacture of the optical switch of the above-mentioned Agilent Technologies, cannot be used for the optical component using surface tension. This is because, as described above, in the optical switch using surface tension, it is necessary to seal each groove independently.

  Furthermore, the optical switch of Agilent Technologies uses silicon as the substrate on which the heater and its wiring are provided, for the reason that it is a convenient material for forming the hole for supplying the liquid. Further, this optical switch is not intended to form a semiconductor element such as a transistor or a diode together with a heater.

  As described above, if the scale of the number of integrated elements of the surface tension-based optical component is increased, the conventional technology requires a large area for wiring, so that the planar optical circuit itself becomes large and the cost increases. There is a problem that leads to. In addition, when a semiconductor element is formed on the surface of a planar optical circuit using a thin film fabrication technique, it is necessary to increase the area to increase the current capacity in order to secure the required current capacity. However, there is a problem that the planar optical circuit itself becomes large. Furthermore, when a heater and a circuit for driving the semiconductor element are manufactured separately from the planar optical circuit and the circuit and the planar optical circuit are anodically bonded, a high temperature and voltage are applied to the semiconductor element. There is a problem of being destroyed.

  The present invention has been made in view of the above situation, and an object of the present invention is to provide an optical waveguide component that suppresses or prevents element degradation that occurs when a semiconductor element is anodically bonded to an optical circuit, and a method for manufacturing the same.

An optical waveguide component according to the present invention that solves the above problems is as follows.
An optical circuit having an optical waveguide and controlling an optical signal propagating through the core part by movement of the refractive index matching liquid in the groove formed across the core part of the optical waveguide;
It is bonded to the optical circuit, a semiconductor element Ru said refractive index matching liquid by the action of heat is moved in the groove by heating by the heater to the portion for controlling said optical signal through a glass layer containing an alkali metal An optical waveguide component formed by anodic bonding ,
In the anodic bonding, an electrode silicon layer is provided on the optical circuit side and a bonding silicon layer is provided on the semiconductor element side with the glass layer interposed therebetween, and the cathode is in electrical contact with the electrode silicon layer. The optical waveguide component is characterized in that the anode is electrically contacted with the bonding silicon layer .

An “optical circuit that controls an optical signal propagating through the core portion of an optical waveguide” is a circuit that controls an optical signal by the action of heat received from a “semiconductor element” on a portion that controls the optical signal in the optical circuit. is there. For example, in the optical component using the surface tension described in the embodiment, the “optical circuit for controlling the optical signal” is an optical circuit having a groove formed so that the refractive index matching liquid is sealed and crosses the optical waveguide. The semiconductor device that controls the propagation direction of the optical signal by driving the refractive index matching liquid, and “acts heat on the part that controls the optical signal” means that the heat is applied to the refractive index matching liquid. It is a semiconductor element that moves and drives a refractive index matching liquid .

In the above optical waveguide component,
The anodic bonding, the substrates of the semiconductor element into contact with the anode, is an optical waveguide component, characterized in that the semiconductor device was carried out electrostatic shield.

An optical circuit having an optical waveguide and controlling an optical signal propagating through the core portion by movement of the refractive index matching liquid in the groove formed across the core portion of the optical waveguide, and the optical circuit And a semiconductor element that moves the refractive index matching liquid in the groove by applying heat to a portion that controls the optical signal by heating with a heater, and is anodically bonded through a glass layer containing an alkali metal. An optical waveguide component comprising:
In the anodic bonding, a bonding silicon layer is provided on the optical circuit side and an electrode silicon layer is provided on the semiconductor element side with the glass layer interposed therebetween, and the anode is in electrical contact with the bonding silicon layer. The optical waveguide component is formed by bringing a cathode into electrical contact with the silicon layer for electrodes .

In the above optical waveguide component,
The anodic bonding, the substrates of the semiconductor element into contact with the cathode, an optical waveguide part, characterized in that the semiconductor device was carried out electrostatic shield.

In the above optical waveguide component,
An optical waveguide component characterized in that an insulating layer is interposed between the semiconductor element and a bonding silicon layer or an electrode silicon layer provided on the semiconductor element side.

In the above optical waveguide component,
The glass plate is an optical waveguide component characterized in that it is a borosilicate glass containing an alkali metal.

The method of manufacturing an optical waveguide component according to the present invention that solves the above problems is as follows.
An optical circuit having an optical waveguide and controlling an optical signal propagating through the core part by movement of the refractive index matching liquid in the groove formed across the core part of the optical waveguide;
It is bonded to the optical circuit, and a semiconductor device of the refractive index matching liquid by the action of heat by heating by the heater Before moving the groove to the portion for controlling said optical signal through a glass layer containing an alkali metal A method of manufacturing an optical waveguide component for anodic bonding ,
In the anodic bonding, an electrode silicon layer and the glass layer are provided in the optical circuit, a bonding silicon layer is provided in the semiconductor element, a cathode is electrically contacted with the electrode silicon layer, and the bonding is performed. The method for producing an optical waveguide component is characterized in that the step is performed between the glass layer and the bonding silicon layer with an anode in electrical contact with the bonding silicon layer .

Further, in the method for manufacturing the optical waveguide component,
The anodic bonding is a method of manufacturing an optical waveguide component, wherein the semiconductor element substrate is brought into contact with an anode and the semiconductor element is electrostatically shielded.

An optical circuit having an optical waveguide and controlling an optical signal propagating through the core portion by movement of the refractive index matching liquid in the groove formed across the core portion of the optical waveguide, and the optical circuit A semiconductor element that is heated and heated by a heater to move the refractive index matching liquid in the groove is anodic bonded via a glass layer containing an alkali metal. A method for manufacturing an optical waveguide component , comprising:
In the anodic bonding, a silicon layer for bonding is provided in the optical circuit, a silicon layer for electrodes and the glass layer are provided in the semiconductor element, and then an anode is electrically contacted with the silicon layer for bonding. A method of manufacturing an optical waveguide component, wherein a cathode is brought into electrical contact with the silicon layer for use, and the process is performed between the glass layer and the bonding silicon layer .

Further, in the method for manufacturing the optical waveguide component,
The anodic bonding is a method of manufacturing an optical waveguide component, wherein the semiconductor element substrate is brought into contact with a cathode and the semiconductor element is electrostatically shielded.

Further, in the method for manufacturing the optical waveguide component,
The anodic bonding is a method of manufacturing an optical waveguide component characterized in that an insulating layer is interposed between the semiconductor element and a bonding silicon layer or electrode silicon layer provided on the semiconductor element.

According to the optical waveguide component and the method of manufacturing the same according to the present invention, an optical waveguide component having a large number of integrated elements, particularly an optical component utilizing surface tension, is manufactured in a small size and at low cost in combination with a semiconductor element. Can do. In addition, it is possible to prevent the adverse effect of alkali metal ions on the semiconductor element by prescribing the direction of voltage application during anodic bonding or by preliminarily protecting the semiconductor element with an insulating layer or the like. .

<First Embodiment>
A first embodiment according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional structure diagram of an optical variable attenuator (optical component using surface tension) according to the present embodiment. As shown in the figure, the optical variable attenuator 10 encloses the refractive index matching liquid 9 in the groove 3 formed so as to cross the core portion 2 of the optical waveguide layer 1, and controls the position of the refractive index matching liquid 9. The level of light propagating through the core unit 2 is adjusted.

  More specifically, the groove 3 is formed to be elongated in a direction perpendicular to the optical axis propagating through the core part 2 so as to cross the core part 2, and the refractive index is partially in the groove 3. Matching liquid 9 is enclosed. The portion other than the refractive index matching liquid 9 in the groove 3 contains, for example, air. By controlling the heater 4 provided in the upper part of the groove 3 to generate a temperature difference at both ends of the elongated groove 3, the position of the refractive index matching liquid 9 and air in the groove 3 is changed, and the core portion 2 The light attenuation function is generated by positioning the refractive index matching liquid 9 or air in the groove 3 that blocks the light.

  Further, only the cross section of one element is shown in the figure, but a plurality of elements are integrated in one optical variable attenuator 10 (integrated in the direction perpendicular to the paper surface of FIG. 1). A fiber block in which a plurality of optical fibers 18 are aligned and fixed is fixed to both ends of the optical variable attenuator 10 with the optical axis of the optical fiber core 19 aligned with the core portion 2 of the optical waveguide layer 1. ing.

  The optical variable attenuator 10 includes a planar optical circuit and a semiconductor element because of its manufacturing method. The planar optical circuit includes a silicon substrate 8, an optical waveguide layer 1 formed on the substrate, and an electrode silicon layer 12 and a bonding alkali glass layer 13 formed thereon. The semiconductor element includes a diode substrate 15, a diode 14 formed on the substrate, a heater 4, a heater wiring 5, an insulating layer 6, and a bonding silicon layer 11 deposited thereon.

  In the planar optical circuit before the semiconductor element is tightly fixed, a conductive electrode silicon layer 12 having a thickness of about 1 μm is deposited on the optical waveguide layer 1, and a borosilicate glass containing an alkali metal is further formed thereon. A certain bonding alkali glass layer 13 is deposited by several μm. And the groove | channel 3 is formed to the depth which cut | disconnects the core part 2 in a planar optical circuit, and the refractive index matching liquid 9 is enclosed in the said groove | channel 3 later.

  The semiconductor element is a diode array in which a diode 14 is connected and inserted in series with the heater 4 at the intersection of the heater wiring 5. A surface layer portion of the semiconductor element is embedded with an insulating layer 6 and a bonding silicon layer 11 is deposited thereon (FIG. 1 shows the semiconductor element in a direction opposite to the deposition direction). The bonding silicon layer 11 is a silicon layer for anodic bonding with the bonding alkali glass layer 13 on the planar optical circuit side, and has a thickness of about 0.3 μm. A cathode electrode wiring 16 and an anode electrode wiring 17 are connected to the diode 14 and are driven by power supply from the wiring.

  The bonding silicon layer 11 on the semiconductor element side and the bonding alkali glass layer 13 on the planar optical circuit side are brought into close contact with each other, and the anode is bonded to the bonding silicon layer 11 while being heated to a temperature of several hundred degrees C. The anode is joined by applying a voltage while bringing the cathode into electrical contact with the lower electrode silicon layer 12. In general, it is known that when a semiconductor element is exposed to a high temperature environment exceeding 450 ° C., the characteristics of the semiconductor element deteriorate, but according to the experience of the present inventors, anodic bonding is performed at a temperature of 450 ° C. or less. When heating was performed for several tens of minutes, which is the time required for completion, there was no deterioration of the FET or diode. The anodic bonding itself can be performed at 200 ° C. to 450 ° C. Therefore, the characteristics of the semiconductor element are not deteriorated only by heating at the time of anodic bonding.

  Since the thermal expansion coefficient of the bonding alkali glass layer 13 is generally different from that of the silicon substrate 8, distortion occurs in the bonding alkali glass layer 13 with cooling from a high temperature during anodic bonding to room temperature. However, when the bonding alkali glass layer 13 is a thin film having a thickness of about several μm, problems such as peeling and destruction of the bonding alkali glass layer 13 do not occur.

  Alkali metal ions such as sodium (Na) and lithium (Li) in the bonding alkali glass layer 13 are easily moved in the glass solid when the bonding alkali glass layer 13 is heated. For this reason, the joining alkali glass layer 13 can be regarded as a conductor under temperature conditions for anodic bonding. Of course, although it is a conductor, the electrical resistance is extremely high, and Pyrex glass, which is a kind of borosilicate glass containing an alkali metal, shows an electrical resistance of about several MΩ at a thickness of about 1 mm, depending on the temperature. .

  However, it is generally known that alkali metal ions such as sodium ions described above are extremely inconvenient for semiconductor elements. Since alkali metal ions have a small ion radius, they are called mobile ions that easily move in a semiconductor solid and cause a reduction in the function of the semiconductor element, and contamination into the semiconductor process is an extremely wary substance.

  For example, in the case of an N-channel MOS-FET, since the alkali metal ions have a positive charge, the gate potential is raised, and as a result, the threshold voltage is lowered. When contamination with alkali metal ions proceeds, a channel may remain formed without applying a gate voltage, and switching operation as an FET becomes impossible.

  In anodic bonding, ion conduction by alkali metal ions contained in glass is indispensable. Therefore, it is inevitable that the bonding alkali glass layer 13 made of borosilicate glass containing alkali metal is brought into contact with the surface of the semiconductor element. For this reason, conventionally, when anodic bonding of glass to a semiconductor element, a part away from the part where the semiconductor element was formed was selected as the bonding part, and the glass was not anodic bonded directly above the semiconductor element.

  However, in the optical component using surface tension shown in this embodiment, it is necessary to install a semiconductor element (dyed 14) close to the groove 3 for sealing the refractive index matching liquid 9 due to its structure. It is inevitable that anodic bonding is used.

  Therefore, in this embodiment, for the purpose of achieving both anodic bonding and suppression of damage to the semiconductor element, the insulating layer 6 made of silica not containing alkali metal ions such as sodium ions is deposited on the surface layer portion of the semiconductor element, and then bonded. A silicon layer 11 is deposited. That is, by providing the insulating layer 6, alkali metal ions are prevented from diffusing into the diode 14 from the bonding alkali glass layer 13 provided on the planar circuit side.

  Further, at the time of anodic bonding, the bonding silicon layer 11 on the semiconductor element side is used as an anode, and the electrode silicon layer 12 on the planar optical circuit side is used as a cathode. As a result, the alkali metal ions in the bonding alkali glass layer 13 move in a direction away from the semiconductor element side that is the anode, so that the entry of the alkali metal ions into the diode 14 can be more reliably prevented. Deterioration of the element can be prevented.

  The bonding silicon layer 11 may be another metal capable of anodic bonding, such as aluminum. In addition to silicon and aluminum, the electrode silicon layer 12 may be any metal that has electrical conductivity such as gold, copper, chromium, or titanium and has high adhesion to the glass material. In addition, when Pyrex glass is used as the bonding alkali glass layer 13, the thermal expansion coefficient with the silicon substrate 8 matches in a wide temperature range, so that distortion due to cooling after anodic bonding can be suppressed. Pyrex glass mainly contains sodium as an alkali metal, but it can suppress distortion even when borosilicate glass containing lithium as an alkali metal and having a thermal expansion coefficient matching that of silicon is used. it can.

<Second Embodiment>
A second embodiment according to the present invention will be described in detail based on the drawings. FIG. 2 is a schematic cross-sectional structure diagram of an optical shutter (surface tension utilizing optical component) according to the present embodiment. As shown in the figure, the optical shutter 20 includes a refractive index matching liquid 9 sealed in a groove 3 formed so as to cross the core part 2 of the optical waveguide layer 1, and the core part is controlled by position control of the refractive index matching liquid 9. Block or transmit light propagating through 2. The method for controlling the position of the refractive index matching liquid 9 is the same as in the first embodiment.

  Further, although only a cross section of one element is shown in the figure, a plurality of elements are integrated (integrated in a direction perpendicular to the paper surface of FIG. Fiber blocks in which a plurality of optical fibers 18 are aligned and fixed are bonded and fixed to both ends of the shutter 20 so that the optical axis of the optical fiber core 19 coincides with the core portion 2 of the optical waveguide layer 1.

  The optical shutter 20 is composed of a planar optical circuit and a semiconductor element because of its manufacturing method. The planar optical circuit includes a silicon substrate 8, an optical waveguide layer 1 formed on the substrate, and a bonding silicon layer 11 formed thereon. The semiconductor element includes an FET substrate 22, an FET 21 formed on the substrate, a heater 4, a heater wiring 5, an insulating layer 6, and an electrode silicon layer 12 and a bonding alkali glass layer 13 deposited thereon. Consists of

  In a planar optical circuit before the semiconductor element is closely fixed, a bonding silicon layer 11 of about 1 μm is deposited on the optical waveguide layer 1. And the groove | channel 3 is formed to the depth which cut | disconnects the core part 2 in a planar optical circuit, and the refractive index matching liquid 9 is enclosed in the said groove | channel 3 later. The bonding silicon layer 11 is a silicon layer for anodic bonding with the bonding alkali glass layer 13 on the semiconductor element side.

  In the semiconductor element, an array of heaters 4 and a circuit for individually controlling the heaters 4 by FETs 21 are formed on an FET substrate 22. A surface layer portion of the semiconductor element is embedded with an insulating layer 6, an electrode silicon layer 12 is further deposited thereon, and a bonding alkali glass layer 13 is further deposited thereon (in FIG. 2, the direction opposite to the deposition direction). The semiconductor element is shown in the orientation). The insulating layer 6 is made of silica as a material, and the joining alkali glass layer 13 is pyrex glass made of borosilicate glass containing an alkali metal, and has a thickness of several μm. A drain electrode wiring 23, a gate electrode wiring 24, and a source electrode wiring 25 are connected to the FET 21 and are driven by power supply from the wiring.

  The bonding alkali glass layer 13 on the semiconductor element side and the bonding silicon layer 11 on the planar optical circuit side are in close contact, and the electrode silicon layer 12 under the bonding alkali glass layer 13 is heated to a temperature of several hundred degrees Celsius. An anode is bonded by applying a voltage by bringing the cathode into contact with the anode and the anode in contact with the bonding silicon layer 11. The deterioration of the semiconductor element due to the temperature during anodic bonding is as described above.

  In the present embodiment, the direction in which a voltage is applied is opposite to that in the first embodiment, and the semiconductor element side is a cathode. Therefore, sodium ions in the bonding alkali glass layer 13 move in a direction toward the semiconductor element side that is the cathode. However, in the surface layer of the semiconductor element, an electrode silicon layer 12 (cathode) having a negative potential is provided between the FET 21 and the bonding alkali glass layer 13. That is, since the potential of the electrode silicon layer 12 is the lowest, sodium ions that have moved toward the semiconductor element are captured by the electrode silicon layer 12 and do not penetrate through the insulating layer 6 and diffuse to the FET 21.

  Further, by bringing the substrate 21 of the semiconductor element together with the electrode silicon layer 12 into contact with the cathode so as to have the same potential, the electric field inside the semiconductor element is shielded from the outside and becomes completely the same potential, so that the penetration of sodium ions is ensured. Can be prevented.

  The electrode silicon layer 12 may be a metal having high adhesion to other metal materials, for example, glass materials such as aluminum, chromium, and titanium. Pyrex glass mainly contains sodium as an alkali metal, but suppresses distortion even when borosilicate glass containing lithium as an alkali metal and having a thermal expansion coefficient matching that of silicon is used. be able to.

<Third Embodiment>
A third embodiment according to the present invention will be described in detail with reference to the drawings. FIG. 3 is a schematic cross-sectional structure diagram of a matrix optical switch (optical component using surface tension) according to the present embodiment. As shown in the figure, the matrix optical switch 30 encloses the refractive index matching liquid 9 in the groove 3 formed so as to cross the intersection at the intersection where a plurality of core portions 2 of the optical waveguide layer 1 intersect. The propagation direction of the optical signal is switched between the plurality of core portions 2 by controlling the position of the rate matching liquid 9. The method for controlling the position of the refractive index matching liquid 9 is the same as in the first embodiment.

  In addition, only the cross section of one element is shown in the figure, but a plurality of elements are integrated (integrated in the direction perpendicular to the paper surface of FIG. 3) in one matrix optical switch 30. Fiber blocks in which a plurality of optical fibers 18 are aligned and fixed are bonded and fixed to both ends of the matrix optical switch 30 so that the optical axis of the optical fiber core 19 coincides with the core portion 2 of the optical waveguide layer 1. .

  The matrix optical switch 30 is composed of a planar optical circuit and a semiconductor element because of its manufacturing method. The planar optical circuit includes a silicon substrate 8, an optical waveguide layer 1 formed on the substrate, and a bonding silicon layer 11 formed thereon. And the groove | channel 3 is formed to the depth which cut | disconnects the core part 2 in a planar optical circuit, and the refractive index matching liquid 9 is enclosed in the said groove | channel 3 later. The semiconductor element includes an FET substrate 22, an FET 21 formed on the substrate, a heater 4, a heater wiring 5, and an insulating layer 6. A drain electrode wiring 23, a gate electrode wiring 24, and a source electrode wiring 25 are connected to the FET 21, and the FET 21 is driven by power supply from the wiring.

  A pyrex lid 31 is anodically bonded on the bonding silicon layer 11 and the groove 3 is hermetically sealed. The Pyrex lid 31 is manufactured by grinding and polishing, and has a thickness of several tens of μm. After the Pyrex lid 31 is anodically bonded, the surface on the side to which the semiconductor element is attached is further ground and polished until the thickness becomes 10 μm or less.

  An optical component is manufactured by closely fixing the semiconductor element with the adhesive 32 to the Pyrex lid 31 whose surface has been polished in this way. That is, in this embodiment, since anodic bonding is performed only in a planar optical circuit, an optical component can be manufactured without heating and applying a voltage to the semiconductor element, and damage to the semiconductor element is eliminated. be able to.

  The thin Pyrex lid 31 is formed by, for example, applying or depositing a material that can be easily dissolved and removed by post-processing on the surface of a flat substrate, and then depositing Pyrex glass on the surface by sputtering or the like, thereby easily dissolving the underlying material. Can be prepared by dissolving it with a solvent or the like. Thus, when the Pyrex lid 31 is produced separately from the planar optical circuit, patterning such as forming a hole in the Pyrex lid can be performed before anodic bonding with the planar optical circuit. If a Pyrex lid having a desired thickness is formed in advance, grinding and polishing operations for reducing the film thickness after anodic bonding can be eliminated.

1 is a schematic cross-sectional structure diagram of an optical variable attenuator (optical component using surface tension) according to a first embodiment. It is a schematic sectional structure figure of the optical shutter (surface tension utilization type optical component) concerning a 2nd embodiment. It is a schematic cross-section figure of the matrix optical switch (surface tension utilization type optical component) which concerns on 3rd Embodiment. It is a schematic cross-section figure of the conventional surface tension utilization type | mold optical component.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical waveguide layer 2 Core part 3 Groove 4 Heater 5 Wiring 6,6 'Insulating layer 8 Silicon substrate 9 Refractive index matching liquid 10 Optical variable attenuator 11 Silicon layer for joining 12 Silicon layer for electrodes 13 Alkali glass layer for joining 14 Diode DESCRIPTION OF SYMBOLS 15 Diode board | substrate 16 Cathode electrode wiring 17 Anode electrode wiring 18 Optical fiber 19 Optical fiber core

20 Optical shutter 21 FET
22 FET substrate 23 Drain electrode wiring 24 Gate electrode wiring 25 Source electrode wiring

DESCRIPTION OF SYMBOLS 30 Matrix optical switch 31 Pyrex lid 32 Adhesive 40 Surface tension utilization type optical component 41 Optical waveguide layer 42 Core part 43 Groove 44 Heater 45 Wiring 46 Insulating layer 47 Pyrex lid 48 Silicon substrate 49 Refractive index matching liquid 50 Bonding silicon layer 51 Optical fiber 52 optical fiber core

Claims (11)

An optical circuit having an optical waveguide and controlling an optical signal propagating through the core part by movement of the refractive index matching liquid in the groove formed across the core part of the optical waveguide, and bonded to the optical circuit And a semiconductor element that moves the refractive index matching liquid in the groove by applying heat to the part that controls the optical signal by heating with a heater, and the optical circuit and the semiconductor element contain an alkali metal. An optical waveguide component that is anodically bonded through a glass layer,
In the anodic bonding, an electrode silicon layer is provided on the optical circuit side and a bonding silicon layer is provided on the semiconductor element side with the glass layer interposed therebetween,
An optical waveguide component characterized by being carried out by bringing a cathode into electrical contact with the electrode silicon layer and bringing an anode into electrical contact with the bonding silicon layer. In the optical waveguide component according to claim 1,
The optical waveguide component, wherein the anodic bonding is performed by bringing a substrate of the semiconductor element into contact with an anode and electrostatically shielding the semiconductor element. An optical circuit having an optical waveguide and controlling an optical signal propagating through the core part by movement of the refractive index matching liquid in the groove formed across the core part of the optical waveguide, and bonded to the optical circuit And a semiconductor element that moves the refractive index matching liquid in the groove by applying heat to the part that controls the optical signal by heating with a heater, and the optical circuit and the semiconductor element contain an alkali metal. An optical waveguide component that is anodically bonded through a glass layer,
In the anodic bonding, a silicon layer for bonding is provided on the optical circuit side and a silicon layer for electrodes is provided on the semiconductor element side with the glass layer interposed therebetween,
An optical waveguide component characterized by being performed by bringing an anode into electrical contact with the bonding silicon layer and electrically contacting a cathode with the electrode silicon layer. In the optical waveguide component according to claim 3,
The optical waveguide component, wherein the anodic bonding is performed by bringing a substrate of the semiconductor element into contact with a cathode and electrostatically shielding the semiconductor element. In the optical waveguide component according to any one of claims 1 to 4,
An optical waveguide component comprising an insulating layer interposed between the semiconductor element and a bonding silicon layer or electrode silicon layer provided on the semiconductor element side. In the optical waveguide component according to any one of claims 1 to 5,
The optical waveguide component, wherein the glass plate is borosilicate glass containing an alkali metal. An optical circuit having an optical waveguide and controlling an optical signal propagating through the core part by movement of the refractive index matching liquid in the groove formed across the core part of the optical waveguide, and bonded to the optical circuit The optical signal for anodic bonding the semiconductor element for causing the refractive index matching liquid to move in the groove by applying heat to the portion that controls the optical signal by heating with a heater through a glass layer containing an alkali metal. A method for manufacturing a waveguide component, comprising:
In the anodic bonding, an electrode silicon layer and the glass layer are provided in the optical circuit, a bonding silicon layer is provided in the semiconductor element, a cathode is electrically contacted with the electrode silicon layer, and the bonding is performed. A method for producing an optical waveguide component, wherein the method is performed between the glass layer and the bonding silicon layer by bringing an anode into electrical contact with the bonding silicon layer. In the manufacturing method of the optical waveguide component according to claim 7,
The anodic bonding is performed by bringing a substrate of the semiconductor element into contact with an anode and electrostatically shielding the semiconductor element. An optical circuit having an optical waveguide and controlling an optical signal propagating through the core part by movement of the refractive index matching liquid in the groove formed across the core part of the optical waveguide, and bonded to the optical circuit And an optical device for anodic bonding a semiconductor element that moves the refractive index matching liquid in a groove by applying heat to a portion that controls the optical signal by heating with a heater through a glass layer containing an alkali metal. A method for manufacturing a waveguide component, comprising:
In the anodic bonding, a silicon layer for bonding is provided in the optical circuit, a silicon layer for electrodes and the glass layer are provided in the semiconductor element, and then an anode is electrically contacted with the silicon layer for bonding. A method for producing an optical waveguide component, comprising: bringing a cathode into electrical contact with a silicon layer for use, and performing the step between the glass layer and the bonding silicon layer. In the manufacturing method of the optical waveguide component according to claim 9,
The anodic bonding is performed by bringing a substrate of the semiconductor element into contact with a cathode and electrostatically shielding the semiconductor element. In the method for manufacturing an optical waveguide component according to any one of claims 7 to 10,
The anodic bonding is performed by interposing an insulating layer between the semiconductor element and a bonding silicon layer or an electrode silicon layer provided on the semiconductor element.

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