WO2022180835A1

WO2022180835A1 - Optical waveguide device and optical waveguide manufacturing apparatus and manufacturing method

Info

Publication number: WO2022180835A1
Application number: PCT/JP2021/007520
Authority: WO
Inventors: 慶太山口; 雅太田; 賢哉鈴木
Original assignee: 日本電信電話株式会社
Priority date: 2021-02-26
Filing date: 2021-02-26
Publication date: 2022-09-01
Also published as: JPWO2022180835A1

Abstract

In the present invention, manufacturing processing for manufacturing an optical waveguide has, in a step for manufacturing an optical waveguide, a step for forming a processing information element that corresponds to a waveguide constituent element of the optical waveguide in the same step as the waveguide constituent element, and forming a marker that includes the processing information element.

Description

Optical waveguide device, optical waveguide manufacturing apparatus and manufacturing method

The present invention relates to an optical waveguide device, an optical waveguide manufacturing apparatus, and a manufacturing method, and more particularly, to a processing technique for elements constituting an optical waveguide.

Optical devices such as semiconductor lasers, photodiodes, optical wavelength multiplexers/demultiplexers, and optical switches are configured with optical integrated circuits. In optical fiber communication, not only the optical fiber as a transmission medium but also the optical integrated circuits in these optical devices for performing optical signal processing play an important role (see, for example, Non-Patent Document 1). A semiconductor laser is an optical oscillator that generates a light wave for superimposing a signal, and a photodiode operates as an element that converts the intensity of an optical signal into an electrical signal. An optical wavelength multiplexer/demultiplexer represented by an arrayed waveguide grating is used for wavelength division multiplex communication as an element for multiplexing/demultiplexing different wavelengths of light (see, for example, Non-Patent Document 2). An optical switch has an important function in a ROADM (Reconfigurable Optical Add/Drop Multiplexing) system as an element that routes optical paths. These optical integrated circuits are generally composed of an optical waveguide formed on a substrate. An optical waveguide consists of a core through which an optical signal propagates and a clad surrounding it. Semiconductor lasers and photodiodes are made of semiconductor materials such as InP, and arrayed waveguide gratings and optical switches are made of optical waveguide materials mainly made of silica glass.

FIG. 1 is a block diagram showing a method of manufacturing an optical waveguide. A quartz-based planar lightwave circuit made of quartz-based glass will be described as an example. First, in a lower clad deposition step 1, a glass film that will become a lower clad 12 is deposited on a silicon substrate (wafer) 11 . The lower clad 12 is made of, for example, SiO ₂ added with P ₂ O ₅ or B ₂ O ₃ deposited by flame hydrolysis deposition (FHD). The soot-like glass particles deposited by the FHD method are heated at a high temperature of 1000° C. or higher to obtain a transparent lower clad 12 . Next, in the core depositing step 2, the FHD method is also used to deposit a thin film glass that will become the core 13 having a higher refractive index than the lower clad 12 . In depositing the core 13, a desired refractive index value can be obtained, for example, by adding GeO ₂ to SiO ₂ . A transparent core 13 is formed by heating at a high temperature of 1000.degree. Incidentally, the formation of these lower clad and core is not limited to the FHD method, and of course other well-known methods may be used.

In the photoresist film-forming step 3, a photoresist film 14 is formed on the substrate by spin coating. Next, in the circuit pattern exposure step 4, the photoresist film is irradiated with UV light 16 through a photomask 15 to expose a circuit pattern corresponding to the mask pattern. Then, in the photoresist development step 5, the circuit pattern of the photoresist film is developed to obtain a photoresist pattern 17. FIG.

Next, in etching step 6, the photoresist pattern 17 is transferred to the core by reactive ion etching (RIE) to obtain a core pattern 18. Then, in the resist removing step 7, the photoresist remaining on the core is removed by ashing. Finally, in the upper clad deposition step 8, the upper clad 19 is deposited by the same method as the lower clad deposition in the lower clad deposition step 1. FIG.

　The optical waveguide obtained in the above manufacturing process is inspected for various characteristics such as optical characteristics. Conventionally, in order to reflect the inspection results in the manufacturing process, manufacturing conditions reflecting the inspection results are set in each process after a series of processes are completed. This method has the problem that manufacturing errors accumulate in each process, so that the accuracy of the inspection results becomes lower in later processes. On the other hand, the accumulation of manufacturing errors can be suppressed by resetting the manufacturing conditions of the process or adjusting the manufacturing conditions of the subsequent process based on the inspection results obtained at the end of one process. However, there is a problem that the manufacturing process is interrupted after each process, making it difficult to improve the throughput of the manufacturing process.

Therefore, if information on the processing result obtained in a certain process, for example, information on the width of the resist pattern obtained in the photoresist development process, can be known during the development process, information on the pattern width can be obtained in the subsequent etching process. It is possible to implement a process that reflects Further, if the film thickness and refractive index of the core obtained in the core deposition process can be known during the deposition process, it is possible to predict the optical characteristics of the optical waveguide formed in the subsequent process. In this way, by acquiring the information of the optical waveguide component obtained in the previous process during the previous process, it can be reflected in the processing conditions of the subsequent process or used to predict the optical characteristics obtained in the subsequent process. If it can be done, it is convenient in terms of the throughput of the manufacturing process.

As described above, when acquiring the information (processing information) on the processing result in the previous process, it is conceivable to image the shape of the waveguide formed in the previous process over the entire path of the waveguide. be done. However, it is relatively difficult to image all paths along which optical signals propagate at a high magnification and measure the shape. In order to acquire the shape of the waveguide in detail, high-magnification imaging is necessary. This is because it is necessary to increase the number of pixels, resulting in a decrease in throughput and an increase in storage memory capacity for imaging information.

An object of the present invention is to provide an optical waveguide device, an optical waveguide manufacturing apparatus, and a manufacturing method that make it possible to acquire processing information without reducing throughput in one process of manufacturing an optical waveguide.

According to one aspect of the present invention, there is provided a manufacturing method for executing a plurality of steps for manufacturing an optical waveguide in time series, wherein in the plurality of steps, processing information elements corresponding to waveguide constituent elements of the optical waveguide are: forming a marker in the same process as the waveguide component and including the processing information element; measuring the processing information element corresponding to the component, and controlling the formation of the waveguide component in the j-th step after the i-th step in chronological order based on the measurement result. and a step.

In another aspect of the present invention, there is provided a manufacturing apparatus for executing a plurality of steps for manufacturing an optical waveguide in time series, wherein in the plurality of steps, processing information elements corresponding to waveguide constituent elements of the optical waveguide are generated. , means for forming in the same step as the waveguide constituent element and controlling to form a marker including the processing information element; a step of measuring processing information elements corresponding to the waveguide constituent elements thus obtained; and a step of controlling formation of the waveguide constituent elements in the j-th step subsequent to the i-th step in chronological order based on the measurement results. and means for performing

It is a block diagram which shows the manufacturing method of an optical waveguide. It is a figure explaining the manufacturing method of the optical waveguide concerning one Embodiment of this invention. 1 is a generalized diagram of a feedforward system according to an embodiment of the invention; FIG. FIG. 2 is a diagram illustrating the basic configuration of a waveguide pattern formed on a substrate and a marker formed together with this pattern, according to the first embodiment of the present invention; (a) and (b) are diagrams illustrating a marker according to another embodiment of the present invention. 5 is a flowchart illustrating an example of correction using markers in the manufacturing process of the optical waveguide according to the embodiment of the present invention; FIG. 5 is a diagram illustrating an example of prediction using markers in the manufacturing process of the optical waveguide according to the embodiment of the present invention; FIG. 10 is a diagram showing a marker according to a second embodiment of the invention; FIG. 10 is a diagram showing a marker according to a third embodiment of the invention;

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In the manufacturing method according to the embodiment of the present invention, the constituent elements or characteristics of the optical device formed in one step of the manufacturing process are measured at that time, and based on the measured data, the manufacturing conditions of the post-process are measured. (This method is hereinafter referred to as a “feedforward system.”) The feedforward system adjusts or corrects the desired optical characteristics of the finally obtained optical device, such as suppressing variations in the optical characteristics of the optical device. allows you to obtain

FIG. 2 is a diagram illustrating an example of a method for manufacturing an optical waveguide according to one embodiment of the present invention. The feedforward system "measures" the components of the optical device formed in one process, and performs "optical property estimation" by the optical property estimation processing 21 based on the measurement results. Then, based on the estimation result, the process control processing 22 performs "control" of the post-process.
For example, the refractive index and thickness of the lower clad film formed in the lower clad deposition step 1 and the refractive index and thickness of the core layer deposited in the core deposition step 2 are “measured”. Based on the results of this measurement, the final optical properties of devices fabricated with standard (nominal) design values are estimated. Then, based on this estimation, in the subsequent etching step 6, the etching intensity or time is "controlled".

Specifically, based on the "measured" thickness and refractive index of the core layer and the refractive index of the clad film, the ideal core width of the pattern to meet the performance required for the optical device is estimated (predicted). do. Then, in the etching step 6, etching is performed based on this predicted value. For example, in the case of prediction information that the standard (nominal) design value is "the waveguide width after core processing is thick" and the desired performance cannot be satisfied, the etching process is used to correct the width of the formed core. I do. As an adjustment method at this time, a method of thickening/thinning the core width by shortening/longening the etching time or weakening/strengthening the etching intensity can be considered. Furthermore, the core width and steps in the waveguide pattern formed in the etching process 6 are "measured", and based on the measurement results, the refractive index of the upper clad film formed in the upper clad deposition process 8, etc. are "controlled". However, it is also possible to adjust the optical characteristics of the finally obtained optical waveguide.

As described above, the feedforward system of the present embodiment measures the shape, characteristics, etc. of the constituent elements of the optical device formed during or after the preceding process of the plurality of processes for manufacturing the optical device. , based on the measurement results, the manufacturing conditions in the post-process are adjusted or corrected so that the performance of the finally completed device satisfies the desired conditions.

FIG. 3 is a diagram showing a generalized feedforward system according to an embodiment of the present invention. The feedforward system includes an optical device manufacturing procedure consisting of M steps, and an optical device, which is an object to be manufactured, is divided into steps 1, 2, . . . , step i, . M order. Here, when i<j, the process j is a process later than the process i. The feedforward system includes a measurement data processing section 31 and a control data processing section 32 . The measurement data processing unit 31 executes the optical property estimation processing 21 described above with reference to FIG. 2, and the control data processing unit 32 executes the process control processing 22. FIG. The measurement data processing unit 31 and the control data processing unit 32 can be in the form of a computer configured with a CPU, RAM, ROM, and the like.

　In Figure 3, the solid line indicates the flow according to the manufacturing process. Also, dashed lines indicate measurement data obtained by "measurement" of each process, and one-dot chain lines indicate control data for "control" of each process. As described above, the feedforward system of the present embodiment acquires measurement data from the manufacturing apparatus involved in the production or from the measurement apparatus, and transfers the measurement data to the measurement data processing unit 31 in step i. The measurement data processing unit 31 predicts the shape or characteristics of the components of the optical device formed in step i based on the measurement data. Alternatively, the optical properties of the optical device finally obtained in step i may be predicted based on the measurement data.

The predicted value derived by the measurement data processing unit 31 is passed to the control data processing unit 32. Based on the predicted value, the control data processing unit 32 obtains the manufacturing conditions for the subsequent step j. The control data processing unit 32 supplies control data for the process j to be set in the manufacturing apparatus according to the obtained manufacturing conditions when the process j is executed. The control data based on the pre-process supplied when executing the post-process j may be only control data based on the pre-process i, or a plurality of types of control data based on some of the pre-processes. good too. It goes without saying that the form is determined according to conditions such as the actually constructed manufacturing apparatus and the manufacturing object.

A configuration for acquiring processing information in one process of manufacturing a waveguide using the feedforward system described above will be described below.

(basic configuration)
Below, first, a basic configuration for acquiring processing information according to an embodiment of the present invention will be described.

FIG. 4 is a diagram for explaining the basic configuration of an embodiment of the present invention, and is a diagram for explaining a waveguide pattern formed on a substrate and a marker formed together with this pattern. FIG. 4 shows an AWG waveguide pattern 100 as an example of a waveguide and a marker 200 formed with this pattern.

As shown in FIG. 4, the AWG waveguide pattern 100 includes a bent portion 101, a tapered portion 102, a straight portion 103, and the like as constituent elements that determine the shape of the waveguide. Note that the constituent elements are not limited to these, and can be determined according to how processing information obtained from markers, which will be described later, is used, such as the shape of the target waveguide pattern. For example, in addition to the bends, tapers, and straight portions described above, there are crossing portions, directional coupler portions, and the like. Further, in the example shown in FIG. 4, the marker 200 is formed at substantially the center of the AWG waveguide pattern 100 in the same process as that of the optical waveguide described in FIG. 1, together with the optical waveguide. This marker 200 is: As shown on the right side of FIG. 4, it is approximately square with a size of about 100 μm×100 μm. On the other hand, the waveguide pattern 100 has a size of approximately several tens of millimeters×several tens of millimeters, as shown on the left side of FIG. 4 (see Non-Patent Document 2).

The marker 200 is formed by integrating elements having basically the same shape as part of the constituent elements of the waveguide. In the example shown in FIG. 4, for example, a waveguide tapered portion 102 is shown as a component of the waveguide, which is formed in the marker 200 as a processing information element 102M. Similarly, the straight portion 103 of the waveguide is formed in the marker 200 as a straight processing information element 103M.

In this way, by forming and imaging the marker 200 in which the constituent elements of the waveguide are integrated in the manufacturing process of the waveguide, it is possible to represent the processing information of the manufacturing process. Fabrication shapes such as bends, tapers, crosses, straight lines, etc. of waveguide components affect the optical propagation properties of waveguides. In addition, even if the wafers have the same shape, the processing results may be uneven within the wafer surface due to manufacturing variations during manufacturing. Therefore, by consolidating the information of the processing information elements (hereinafter also simply referred to as "processing information") in the marker 200 formed in the same process, correction in the post-process and adjustment of optical characteristics can be performed based on this processing information. Predictions can be made.

The processing information elements formed in the marker 200 are basically the same as the parameter values of the waveguide constituent elements in the waveguide pattern 100 to be manufactured. For example, if the component is a "straight line", a straight line in the marker 200 is formed with the same width as its "width" as a parameter. Similarly, if the component is "bending", the parameters are "width" and "bending radius", if "taper", the parameters are "taper ratio" and "taper start & end point width", and "intersection" , the parameter is the 'crossing angle', and for a 'directional coupler' the parameters are the 'waveguide width' and the 'spacing' of the waveguides. In the marker 200, a processing information element is formed with these parameters having the same values as the waveguide pattern. It goes without saying that the parameter for each component of the waveguide is not limited to the above example. Of course, it can be appropriately determined according to the processing information to be acquired and its intended use.

In this embodiment, the marker 200 described above is formed, and processing information is acquired therefrom. Accordingly, it is possible to obtain the processing information by imaging only the marker. As a result, it is possible to acquire processing information with high throughput. When the marker of this embodiment is not used, for example, when imaging the constituent elements of the entire waveguide with high resolution, there are problems such as an increase in the number of times of imaging and an increase in the amount of memory for imaging data. As a result, in order to determine the processing state, it is necessary to observe and measure the shape after processing across the wafer surface, which complicates the process and lowers the throughput.

It is desirable that the size and shape of the marker 200 be as small as possible so as not to affect the waveguide pattern. On the other hand, the entire marker must fit within the imaging field of view, and the shape of the imaging device is generally rectangular. From these points, it is desirable to fit the marker 200 within the rectangular range accordingly. For example, for a chip size of 10 mm×10 mm, if the size of the marker 200 is 1 mm×1 mm, the imaging size required for inspection is 1/100. becomes 1 in 10000. This indicates that the throughput is 100 times and 10000 times higher, respectively, when measured at similar microscope magnifications. In order to improve the throughput, it is desirable that one side of the marker 200 is 1/10 or less of the length of one side of the chip, or the area of the marker 200 is 1/100 or less of the chip. Also, even if the chip size is 500 μm×500 μm, if the size of the marker 200 is 100 μm×100 μm, the imaging size required for inspection is reduced to 1/25. This represents a 25-fold increase in throughput when measured at the same microscope magnification.

It should be noted that the processing information elements in the marker 200 do not need to have the same parameter value for all the constituent elements of the waveguide. Examples of these are described below.

For example, if the component is "bending", the radius of the waveguide pattern formed is as large as mm order for silica-based waveguides, etc., and the range required for imaging becomes large. In such a case, in the marker, a processing information element having a smaller value for the parameter "bend radius" is formed. When acquiring processing information elements from the marker 200, processing information corresponding to the ratio of the reduced "bending radius" is acquired. Specifically, according to the above-mentioned "bending radius" which is smaller than the actual bending radius in the waveguide pattern, waveguides with a plurality of bending radii are prepared in advance, and the formation results (waveguide width, etc.) are obtained. , to compare with the actual waveguide pattern. Then, in the comparison result, the actual bending radius forming result (processing information) in the waveguide pattern can be extrapolated and estimated according to the ratio of the bending radii. As a characteristic of the "bending" portion, even if the bending radius of the marker 200 is different from the actual bending radius of the waveguide pattern, the shape (processing information) of the bending portion can be estimated based on the different bending radius of the marker 200. However, it is known that the shape of the "bent" portion is close to the shape of the actually formed bent portion. As described above, even when the radius of the waveguide pattern actually formed is large, it is possible to fit the processing information within the size of the marker 200 .

As another example, only part of the bending of the waveguide component may be formed within the marker 200 as the processing information element. FIG. 5(a) is a diagram showing the configuration. As shown in FIG. 5(a), only a portion of the bend 100 of the waveguide component is formed in the marker 200 as a processing information element 100M. In this way, it is possible to fit the processing information within the size of the marker 200 by using the processing information element 100M as the bending portion corresponding to a part of the angle of the bending. That is, only a part of the processing information element 100M cannot know the difference (angle dependence) according to the positional relationship with the bent portion in the actual waveguide pattern, but the representative point of the processing information element 100M From the formation result of the processing information element 100M at (angle), it can be estimated that the same formation result (processing information) is obtained at other angles.

As yet another example, if the waveguide component is a circular arc as a type of bending, it may be equally divided and formed in the marker 200 as the processing information element. FIG. 5(b) is a diagram showing the configuration. As shown in FIG. 5(b), the arc 100 of the waveguide component is divided into four equal arc portions 100A, 100B, 100C and 100D. Then, processing information elements 100MA, 100MB, 100MC, and 100MD corresponding to them are formed in the marker 200. FIG. At this time, the directions or angles of the processing information elements 100MA, 100MB, 100MC, and 100MD are made different. Specifically, they are arranged at regular intervals in the circumferential direction. This makes it possible to make the formation range more compact. By equally dividing the bending into the processing information elements 100M in this manner, the processing information can be contained within the size of the marker 200. FIG. That is, interpolation of these four pieces of discrete information (values) for four pieces of information of formation results (core width, etc.) for each representative point (angle) of the four machining information elements 100MA, 100MB, 100MC, and 100MD. Thus, the formation result (processing information) in the actual waveguide pattern can be estimated.

As in the example shown in FIG. 5B, the processing information element 100M may be formed in the marker 200 in a direction or angle different from the orientation or angle at which the waveguide component 100 is formed. It takes into account the effects of gender. That is, from the information of the formation results (core width, etc.) of the processing information elements at different angles in the marker 200, the respective angle dependencies are calculated, and based on the calculation results, the formation results (processing information) at other angles are calculated. can be estimated. In particular, any angle can be expressed as long as the processing information elements are perpendicular to each other. Specifically, the orientation or angle of the waveguide component on the substrate may affect the manufacturing process differently. Therefore, the following configuration can be adopted. First, when the arrangement direction of the same component in the waveguide pattern is constant, it is desirable that the processing information elements formed in the marker are formed in the same direction. Second, it is desirable to place identical components in the waveguide pattern at different angles in the marker, preferably orthogonal angles. Third, when the component is an "arc", it is desirable that the marker divides the arc at equal intervals and arranges them with different orientations or angles, as described with reference to FIG. 5(b).

In addition, the distribution of a predetermined pattern in the waveguide pattern to be formed may be measured, so it is desirable that a plurality of identical patterns exist within the substrate. Thereby, for example, based on the difference in the formation result between markers in each of the plurality of patterns, it is possible to calculate the change in the formation result (core width, etc.) corresponding to the coordinates on the wafer.

The processing information is not limited to the shape information of the waveguide constituent elements described above. For example, the following information can also be used.
The average value of the waveguide width actually formed with respect to the desired waveguide width (design value) of the waveguide pattern, and the undulations and roughness of the waveguide surface and side surfaces.
・Actually formed waveguide width for each design value of waveguide width (design waveguide width dependence of difference between design value and actual value)
・The point that the width of the formed waveguide differs depending on the bending radius, or the point that the width of the waveguide formed at the waveguide angle at the bending radius used differs. (including average, waviness, roughness, etc.)
・Brightness distribution and brightness of the captured image of the waveguide pattern. Based on this, information on the roughness of the machined surface and the machined height is obtained.

The processing information element in the mark 200 described above can be used for correction in the post-process by forming and acquiring it during the manufacturing process. Also, based on the acquired processing information, it is possible to estimate and predict the optical characteristics of the optical waveguide to be finally manufactured. The estimation and prediction of the characteristics based on the acquired processing information described above are not limited to the optical waveguide that is finally manufactured, and are used to estimate and predict the characteristics of resist patterns formed during the manufacturing process. It is clear from the following description that Next, their basic configurations will be described.

(Correction based on processing information)
In one embodiment of the present invention, a marker is formed together in one step of the waveguide manufacturing process, processing information is acquired from the marker, and the processing information is used to correct processing in subsequent steps.

For example, in the photoresist development process, if processing information indicating that the formed resist pattern is thicker than a predetermined value is acquired from the processing information element of the mark 200 formed in the same process, in the post-process etching process, the processing information indicating that the etching time The width of the waveguide formed in the etching process is set to the desired value (design value) by making corrections such as /lengthen/strengthen the strength. Conversely, if processing information indicating that "the resist pattern is thinner than a predetermined value" is acquired, a correction is made to "shorten/lower the etching time/strength".

As another example, after the etching process of manufacturing the waveguide, the core width is measured from the processing information element of the mark 200 formed in that process. Also, the width of the waveguide pattern through which the optical signal actually propagates can be estimated from the measured value. The etching process can etch based on this core width measurement as an additional step. For example, in the case of information that "the waveguide width after etching is thicker than the ideal value", additional etching is performed to correct the formed core width to be thinner. If it is thinner than the desired value, it can be dealt with by, for example, designing the waveguide to be thicker than the desired waveguide width, or by dividing the etching into two times and acquiring the intermediate state. can do. The ideal value of the waveguide width here may be a design value, or may be an ideal waveguide width calculated from the characteristic prediction described later.

It should be noted that when determining etching conditions based on processing information, it is desirable to determine the etching time and the like in consideration of the entrainment of the etching gas.

FIG. 6 is a flowchart illustrating an example of correction using markers in the optical waveguide manufacturing process according to the embodiment of the present invention. Steps S1 to S8 in FIG. 6 represent the steps of manufacturing the optical waveguide described above with reference to FIG. Further, the dicing process shown in step 9 is a process of cutting the wafer of optical waveguides manufactured so far into chips.

In the above manufacturing process, in this example, the waveguide pattern is formed in the photoresist development process of step S5, and the marker 200 is formed (see FIG. 1). As described above with reference to FIG. 4, this marker 200 is formed with processing information elements corresponding to the constituent elements of the waveguide pattern. Then, in the next step S201, the marker 200 is imaged, processing information is acquired from the imaged processing information element, and etching conditions in the subsequent etching step (S6) are calculated based on this processing information. After that, an etching process is performed in step S6. As a result, as described above, for example, when "the resist pattern formed is thicker than a predetermined value", the etching conditions of the etching process are calculated (corrected) as "increasing/increasing the etching time/strength". As a result, the width of the waveguide formed by the etching process can be set to a desired value (design value).

(Prediction of optical properties based on processing information)
In one embodiment of the present invention, a marker is formed together in one step of the waveguide manufacturing process, processing information is obtained from the marker, and the processing information is used to estimate the optical characteristics of the finally obtained optical waveguide. Predict.

FIG. 7 is a diagram illustrating an example of prediction using markers in the optical waveguide manufacturing process according to the embodiment of the present invention. This example utilizes the fact that the optical characteristics of an optical waveguide are determined according to the shape (width and thickness) and refractive index of a core through which light propagates. As shown in FIG. 7, the film thickness and refractive index of the core are obtained after the process of forming the core film. Further, after the etching process, the width of the core pattern is acquired as processing information from the formed marker 200 . Based on the width of the core pattern, the thickness of the core film, and the refractive index, the optical characteristics of the optical waveguide to be finally manufactured are predicted. As shown in FIG. 7, the acquisition (imaging) of the processing information after the etching process is performed in the area corresponding to the marker 200 of the core film 18 formed in this process (in this specification, this area is also referred to as the "marker 200"). ) to image, measure, and obtain the width and refractive index of the core pattern.

Further, based on the processing information obtained as described above with reference to FIG. 7, correction may be made in a post-process. For example, processing information of core film thickness and refractive index in a core film forming process and core pattern width in an etching process are acquired. Then, the etching conditions in the additional process of the etching process are determined. As a result, for example, the optical properties estimated from the core width measured after the etching process are closer to the design values than the optical properties estimated from the core thickness, refractive index, and core width measured after the etching process. case. In other words, as described above, in the case of the processing information that "the core width of the waveguide pattern is thicker than the ideal value", in the etching process, correction is performed to narrow the formed core width in consideration of the wraparound of the etching gas. be able to.

Also, as described above, the same correction can be performed even when the marker 200 is imaged at the stage of resist pattern formation. For example, the optical properties estimated from the core film thickness, refractive index, and resist pattern width measured after the resist pattern formation process are closer to the design values than the optical properties estimated assuming that the resist pattern width is narrow. if close. That is, in the case of the processing information that "the resist pattern width is thicker than the ideal value", in the etching process, it is possible to make a correction to narrow the formed core width in consideration of the entrainment of the etching gas.

As described above, the marker 200 is formed in the same process as the process for manufacturing the optical waveguide shown in FIG. The timing of acquiring the processing information from the processing information element of the marker 200 differs depending on the purpose of use. As shown in the above examples, the processing information may be acquired after the etching process and the photoresist development process, or may be acquired after the upper clad deposition process, in which case the final waveguide pattern is obtained. Close processing information can be acquired.

Also, the processing information may be acquired from the marker 200 in all the steps shown in FIG. 1 instead of acquiring the processing information in some of the steps.

More preferably, after the core deposition step and up to the upper clad deposition step. This is because most of the light passes through the core in the optical waveguide structure, and the shape of the core has the greatest effect on the characteristics. In this case, the acquired data may contain noise.

Specific examples of the markers described above will be described below.

(First embodiment)
As a first embodiment of the present invention, waveguide constituent elements and processing information elements of markers corresponding thereto when manufacturing an AWG waveguide will be described with reference to FIG. 4 described above in the description of the basic configuration. A bend 101, a taper 102 and a straight line 103, which are waveguide constituent elements constituting the AWG waveguide, correspond to the processing

information elements

101M, 102M and 103M of the marker 200, respectively.

The parameters of the waveguide component, bend 101, are waveguide width, bend radius and spacing. Taper 102 is the taper rate, taper start/end waveguide width. A straight line 103 is the waveguide width. Regarding these parameters, in marker 200, machining

information elements

102M and 103M are formed with the same values (taper rate and taper start/end waveguide width, waveguide width) as corresponding tapers 102 and straight lines 103, respectively. Additionally, processing

information elements

102M and 103M are formed in at least two orthogonal orientations or angles.

On the other hand, in the marker 200, the machining information element 101M can have different parameter values than the corresponding bend 101. Specifically, as described above with reference to FIG. 5B, the bend radius is set to a value smaller than that of the actual waveguide component. Waveguide width and spacing are the same parameter values as the corresponding bend 101 . In addition, the processing information elements 101M are formed at four locations with different orientations or angles. Thereby, the processing information element 101M corresponding to the bend 101 can be formed within the size of the marker 200. FIG.

Note that when the taper rate of the taper 102 is small and the difference between the taper start/end waveguide widths is large, the taper becomes longer and the size of the processing information element 102M becomes larger. In this case, for example, the difference between the taper start/end waveguide widths is reduced without making the parameter values the same. As described above, all the parameter values of the waveguide constituent element and the processing information element need not be the same, as described above.

(Second embodiment)
FIG. 8 is a diagram showing a marker according to the second embodiment, showing waveguide constituent elements and processing information elements of the corresponding markers when manufacturing the waveguides constituting the MZI switch. Waveguide components that make up the MZI switch waveguide, bending 101, straight line 103, intersection 104 and directional coupler 105, correspond to processing

information elements

101M, 103M, 104M and 105M of marker 200, respectively.

The parameters of the waveguide component are the bend 101 is the waveguide width and bend radius, and the straight line 103 is the waveguide width. Also, intersection 104 is the intersection angle, and directional coupler 105 is the straight lines of the coupling and their spacing. Regarding these parameters, in the marker 200 these processing

information elements

103M, 104M and 105M are formed with the same values as the corresponding line, intersection and directional coupler 105 respectively. In addition, the processing

information elements

103M and 105M are formed in at least two different orthogonal orientations or angles, and the processing information element 104M is formed in two different orientations or angles.

On the other hand, in the marker 200, the machining information element 101M has a different parameter value than the corresponding bending 101. Specifically, as described above with reference to FIG. 5B, the bend radius is set to a value smaller than that of the actual waveguide component. In addition, the processing information elements 101M are formed at four locations with different orientations or angles. Thereby, the processing information element 101M corresponding to bending can be formed within the size of the marker 200. FIG.

(Third embodiment)
FIG. 9 is a diagram showing a marker according to the third embodiment, showing waveguide constituent elements and processing information elements of the corresponding markers when manufacturing the waveguides constituting the MZI switch. It is substantially the same as the marker according to the third embodiment described above with reference to FIG. 8, and different points will be described below.

In MZI switches, the MZI waveguides and crossovers 104 are often arranged along the same direction, for example, in the PILOSS configuration. Therefore, it is desirable to make the processing information element of the marker 200 the same as the direction in which it is actually arranged. This is because the characteristics of the MZI switch, such as the ON/OFF extinction ratio and its wavelength dependence, and light leaking to other ports, can be determined by the MZI configuration and intersection.

Claims

A manufacturing method for manufacturing an optical waveguide, comprising:
In the step of manufacturing an optical waveguide, forming a processing information element corresponding to a waveguide component of the optical waveguide in the same process as the waveguide component, and forming a marker including the processing information element. A manufacturing method characterized by:
A manufacturing method for executing a plurality of steps for manufacturing an optical waveguide in chronological order,
forming a processing information element corresponding to a waveguide component of an optical waveguide in the same process as the waveguide component in the plurality of steps, and forming a marker including the processing information element;
a step of measuring a processing information element corresponding to a waveguide component formed up to the i-th step in the plurality of steps while performing the plurality of steps; controlling the formation of the waveguide component in a subsequent j-th step in chronological order;
A manufacturing method characterized by having
The manufacturing method according to claim 1 or 2, wherein the waveguide component and the processing information element have the same parameter value.
The manufacturing method according to claim 1 or 2, wherein the waveguide component and the processing information element have different parameter values.
The manufacturing method according to claim 4, characterized in that the waveguide component and the processing information element have parameter values that differ in the sizes of the formed elements.
The manufacturing method according to claim 4, wherein the waveguide component and the processing information element have parameter values that differ in the orientation of the formed element.
The manufacturing method according to claim 1 or 2, characterized in that a plurality of said processing information elements are formed corresponding to one said waveguide component.
A manufacturing apparatus for executing a plurality of steps for manufacturing an optical waveguide in time series,
means for forming, in the plurality of steps, a processing information element corresponding to a waveguide component of an optical waveguide in the same step as the waveguide component, and controlling to form a marker including the processing information element;
a step of measuring a processing information element corresponding to a waveguide component formed up to the i-th step in the plurality of steps while performing the plurality of steps; controlling the formation of the waveguide component in the j-th step later in chronological order;
A manufacturing apparatus characterized by comprising:
An optical waveguide device,
A marker including an optical waveguide and a processing information element corresponding to a waveguide component of the optical waveguide, wherein the marker has a size of 1/10 or less of the length of one side of the optical waveguide pattern. An optical waveguide device characterized by: