JP2019004095A - Sample substrate processing method and sample substrate transfer method - Google Patents

Abstract

A sample substrate processing method capable of processing a sample substrate of any shape in a simple manner at low cost without contaminating the inside of a vacuum processing apparatus is provided. Kind Code: A1 A sample substrate processing method for processing a sample substrate by using a vacuum processing apparatus having a substrate stage on which a support substrate is placed, wherein a photoresist is applied to one main surface of the support substrate. a resist layer forming step of forming a resist layer using the resist layer; a bonding step of bonding the sample substrate to the supporting substrate via the resist layer; a sample substrate processing step of processing the sample substrate using the wafer processing apparatus; and a stripping step of stripping the sample substrate from the resist layer. do. [Selection drawing] Fig. 3

Description

  The present invention relates to a sample substrate processing method for performing processing by introducing a sample substrate into a vacuum processing apparatus, and a sample substrate transport method.

  Silicon carbide (SiC) has characteristics such as a dielectric breakdown electric field that is an order of magnitude larger than silicon (Si), a band gap that is three times larger, and a thermal conductivity that is about three times higher. Therefore, silicon carbide (SiC) is expected to be applied to power devices, high frequency devices, high temperature operation devices, and the like.

  When a semiconductor substrate such as silicon carbide (SiC) is processed (processed) in a semiconductor process using a vacuum processing apparatus, if the object to be processed is a small sample that differs from the normal wafer size, the normal wafer size It cannot be directly introduced into a stage configured to place an object to be processed.

For this reason, conventionally, when a small sample different from the normal wafer size is introduced into the stage of the vacuum processing apparatus, the small sample is pasted on one main surface side of the Si wafer using an adhesive tape, and then the vacuum processing is performed. A method of introducing into the apparatus is conceivable.
A method of applying vacuum oil to one main surface side of the Si wafer and attaching a small sample using the vacuum oil as an adhesive layer is also conceivable.
Furthermore, a method of introducing the sample into the vacuum processing apparatus using a dedicated tray or the like that can support the small sample so as not to move is also conceivable.

However, in the method of attaching a small sample to an Si wafer using an adhesive tape, if the sample is processed by a vacuum processing device, such as a semiconductor process, the components of the adhesive tape are released into the vacuum processing device and the stage is soiled. In addition, there is a problem that it is difficult to peel a small sample from the Si wafer after processing due to shrinkage of the adhesive tape.
Further, when vacuum oil is used as the adhesive layer, there is a concern that the vacuum oil leaks from the edge portion of the Si wafer due to the high fluidity of the vacuum oil, causing the inside of the vacuum processing apparatus to become dirty.

  In addition, when using a dedicated tray suitable for a small sample, the material used is limited to Si or SiC. Therefore, it is costly and realistic to create a dedicated tray for each sample shape using such a material. Absent. In addition, when the thickness of the dedicated tray is thick, a special mechanism is required for conveyance, and since the thermal conductivity is low, there is a problem that the pattern formed on the sample is broken due to a temperature difference. On the other hand, when the thickness of the dedicated tray is thin, the tray itself is also etched by dry etching of the semiconductor process.

  For this reason, for example, in Patent Document 1, in order to suppress the release of components from a resin sheet such as an adhesive tape, a vacuum processing is performed after a processed wafer placed on the resin sheet is unloaded from the vacuum processing apparatus. A method is disclosed in which plasma is generated in the apparatus to remove components of the resin sheet scattered during processing.

JP 2017-054853 A

  However, although the invention disclosed in Patent Document 1 has a configuration in which a resin sheet is attached to a wafer, the sample wafer is not fixed through the resin sheet. There is a demand for a method for performing processing such as a semiconductor process on sample wafers of various shapes at low cost without polluting the inside of the vacuum processing apparatus.

  The present invention has been made in view of the above-described situation, and performs processing on a sample substrate of an arbitrary shape at a low cost by a simple method without fouling the inside of the vacuum processing apparatus. It is an object of the present invention to provide a method for processing a sample substrate and a method for transporting the sample substrate.

That is, the sample substrate processing method of the present invention has the following configuration.
A sample substrate processing method for processing a sample substrate using a vacuum processing apparatus provided with a substrate stage on which a support substrate is placed, wherein a photoresist layer is applied to one main surface of the support substrate by applying a photoresist. A resist layer forming step to be formed; an attaching step for attaching the sample substrate to the support substrate via the resist layer; and a placement for placing the support substrate on which the sample substrate is attached on the substrate stage And a sample substrate processing step of processing the sample substrate using the wafer processing apparatus, and a peeling step of peeling the sample substrate from the resist layer.

  According to the sample substrate processing method of the present invention, when processing a sample substrate having an arbitrary shape different from the substrate shape that can be supported by the substrate stage of the vacuum processing apparatus, the substrate that can be supported by the substrate stage. By sticking a sample substrate to a support substrate having a shape via a resist layer made of a photoresist, the sample substrate can be processed (vacuum processing) without fouling the inside of the vacuum processing apparatus. It becomes possible.

  In addition, since the sample substrate processing method of the present invention merely forms a photoresist, which is frequently used as a semiconductor process, between the support substrate and the sample substrate, the sample substrate can be used as a support substrate at a low cost with a simple process. Can be attached.

  The present invention is further characterized by further comprising a heating step of heating the support substrate to which the sample substrate has been attached between the attaching step and the placing step.

  In the invention, the sample substrate processing step is a step of performing dry etching by irradiating an electron beam or a focused ion beam toward the sample substrate.

  Further, the present invention is characterized in that in the peeling step, the sample substrate is peeled from the support substrate using at least one of ashing, SPM, and organic cleaning.

  Further, the present invention uses the mark indicating the crystal orientation formed on the support substrate in the attaching step so that the crystal orientation of the support substrate matches the crystal orientation of the sample substrate. It is characterized by making it.

  Further, the invention is characterized in that the sample substrate is smaller than the support substrate.

  Further, the invention is characterized in that the sample substrate is indefinite.

The sample substrate transport method of the present invention has the following configuration.
A method for transporting a sample substrate when processing a sample substrate using a vacuum processing apparatus having a substrate stage on which a support substrate is placed, wherein a resist is applied by applying a photoresist to one main surface of the support substrate. A resist layer forming step for forming a layer; an attaching step for attaching the sample substrate to the support substrate via the resist layer; and transporting the sample substrate with the sample substrate attached to the support substrate And a transporting process.

  ADVANTAGE OF THE INVENTION According to this invention, the processing method of the sample substrate which can process with respect to the sample substrate of arbitrary shapes, without polluting the inside of a vacuum processing apparatus, and a simple method at low cost, and a sample It becomes possible to provide a substrate transport method.

It is the perspective view which showed the conveyance method of the sample substrate of this invention in steps. It is sectional drawing which showed the processing method of the sample substrate of this invention in steps. It is the flowchart which showed the processing method of the sample substrate of this invention in steps.

  Hereinafter, a sample substrate processing method and a sample substrate transport method according to an embodiment of the present invention will be described with reference to the drawings. Each embodiment described below is specifically described for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified. In addition, in the drawings used in the following description, in order to make the features of the present invention easier to understand, there is a case where a main part is shown in an enlarged manner for convenience, and the dimensional ratio of each component is the same as the actual one. Not necessarily.

(Sample substrate transfer method)
FIG. 1 is a perspective view showing the sample substrate transport method of the present invention step by step.
When a sample substrate (sample substrate) is transferred by the sample substrate (sample substrate) transfer method of the present invention, first, a support substrate 11 having a shape that can be placed on a transfer tray of a transfer device that performs transfer is prepared. (See FIG. 1 (a)). The support substrate 11 is a semiconductor wafer such as a Si wafer or a SiC wafer. In this embodiment, a Si wafer is used. Such a support substrate 11 is formed with marks 11s such as an orientation flat (orientation flat) and a notch for aligning crystal orientation.

  Next, as shown in FIG. 1B, a resist layer 12 is formed on the one main surface 11a side of the support substrate 11 (resist layer forming step). The photoresist (photosensitive resin) used for forming the resist layer 12 may be a negative type or a positive type. Photoresist (photosensitive resin) is a material that reacts with electromagnetic waves such as semiconductor lasers, metal halide lamps, high-pressure mercury lamps (g-line, h-line, i-line), excimer lasers, extreme ultraviolet light sources, and electron beam sources as photosensitive light sources. I just need it. As the viscosity of the photoresist to be used, one having an optimum viscosity is selected according to the coating method.

  As a method of applying a photoresist (photosensitive resin) to the one main surface 11a side of the support substrate 11 in such a resist layer forming step, a method such as spin coating or slit coating can be used. In this embodiment, the resist layer 12 having a uniform thickness is formed on the side of the main surface 11a of the support substrate 11 by spin coating.

  Next, as shown in FIG.1 (c), the sample board | substrate (sample board | substrate) 13 is stuck on the support substrate 11 through the resist layer 12 formed in the one main surface 11a side of the support substrate 11 (adhesion). Process). In the present embodiment, the sample substrate 13 is a SiC substrate having a shape smaller than the support substrate 11, for example, a shape obtained by dividing a disk into four (small pieces). When adhering such a sample substrate (sample substrate) 13 to the support substrate 11, it is also preferable to apply a small amount of photoresist to the adhering surface 13 a side of the sample substrate 13.

  When the sample substrate (sample substrate) 13 is attached to the support substrate 11, the sample substrate (sample substrate) is aligned with the mark 11 s of the support substrate 11 so that the crystal orientation of the sample substrate (sample substrate) 13 can be easily understood. It is preferable to press the sample substrate 13 against the resist layer 12. For example, it is stuck so that the crystal orientation of the support substrate 11 and the crystal orientation of the sample substrate 13 match. By fixing the sample substrate (sample substrate) 13 in accordance with the mark 11s of the support substrate 11, the substrate is transferred using the transfer device, and then, for example, when the processing is performed in the vacuum processing device, the support substrate in the vacuum container. Using the 11 mark, the sample substrate (sample substrate) 13 can be set in a predetermined direction.

  And what stuck the sample board | substrate (sample board | substrate) 13 through the resist layer 12 formed in the one main surface 11a side of the support substrate 11 which passed through this sticking process S2 is mounted in the conveyance tray of a conveying apparatus. Place and convey (conveying process). This makes it possible to easily transport a sample substrate (sample substrate) 13 having a shape different from that of the support substrate 11, for example, an indeterminate shape, using the transport tray optimized for transporting the support substrate 11. There is no need to prepare another transport tray or the like that matches the shape of the substrate (sample substrate) 13.

(Sample substrate processing method)
FIG. 2 is a cross-sectional view showing the sample substrate processing method of the present invention step by step. FIG. 3 is a flowchart showing the sample substrate processing method of the present invention step by step.
Hereinafter, a case where the processing method of the sample substrate (sample substrate) 13 is a process of removing a part of the surface of the SiC substrate (sample substrate) by dry etching will be described. On the sample substrate (sample substrate) 13, a resist film from which a pattern corresponding to a portion to be removed by an oxide film and dry etching is previously removed is formed on the surface.

The sample substrate (sample substrate) 13 can be produced by a known technique. That is, an oxide film such as SiO ₂ is formed on the surface of the SiC substrate using plasma CVD or the like. In this case, since the oxide film is formed on the entire surface, the positional accuracy in the oxide film forming apparatus is not questioned, so that the normal method can be used. Further, using a photolithography technique, a resist film from which a portion of the resist to be removed by dry etching is removed by resist coating, exposure, development / rinsing, and post-baking is formed on the oxide film.

Next, as shown in FIG. 2A, a resist layer 12 is formed on the support substrate 11 on the one main surface 11a side of the support substrate 11 (resist layer formation step S1). The details of the resist layer forming step S1 are the same as the resist layer forming step in the above-described sample substrate transport method.
Next, as shown in FIG. 2B, a sample substrate (sample substrate) 13 on which a resist layer 12 is applied and an oxide film 14 and a resist film 15 are formed in advance on a support substrate 11 is formed on the resist layer. It sticks through 12 (sticking process S2). The details of the sticking step S2 are the same as those in the sticking step in the above-described sample substrate transport method. In such a sticking step S2, it is preferable to fix the sample substrate (sample substrate) 13 in accordance with the mark of the support substrate 11 as described in the sample substrate transport method.

  Next, a heat treatment (pre-baking) is performed on the object M to which the sample substrate (sample substrate) 13 and the support substrate 11 are attached via the resist layer 12 (heating step S3). Pre-baking here is a heat treatment performed to remove the solvent from the applied resist, and the heat treatment temperature is low enough that the photosensitive material is not thermally decomposed. In the sample substrate processing method of the present invention, such heating step S3 can be omitted.

  The heating temperature and heating time in this heating step S3 may be set in accordance with the recommended pre-baking conditions indicated on the resist data sheet used. Accordingly, contamination can be prevented by removing volatile components from the resist film and suppressing outgas during processing in the vacuum processing apparatus. Further, since the viscosity of the resist layer 12 is improved, the sample substrate (sample substrate) 13 can be more firmly fixed to the support substrate 11.

  Next, as shown in FIG.2 (c), the to-be-processed object M which performed heating process S3 is mounted in the stage (substrate stage) 21 of the vacuum processing apparatus 20 (mounting process S4). The stage (substrate stage) 21 is formed in a shape that can support the support substrate 11 without being displaced, for example.

  Then, an electron beam or a focused ion beam is irradiated toward the sample substrate (sample substrate) 13 in the vacuum processing apparatus 20, and the sample substrate (sample substrate) 13 is based on a semiconductor process using the etching resist layer 15 as a mask. Processing, for example, dry etching is performed (sample substrate processing step S5).

  In the sample substrate processing step S5, since the sample substrate (sample substrate) 13 is adhered to the support substrate 11 by the resist layer 12 using a photoresist that is assumed to be used in a vacuum environment, it is like an adhesive tape or the like. In addition, the resin component is not detached and diffused into the vacuum processing apparatus 20 to be contaminated, and the resist layer 12 is not contracted in the vacuum and fixed to the sample substrate (sample substrate) 13 or the support substrate 11. . In addition, since the photoresist constituting the resist layer 12 has a higher viscosity than oil or the like, the resist layer 12 does not flow out of the stage (substrate stage) 21 in the sample substrate processing step S5.

  Next, as shown in FIG. 2D, the resist layer 12 is peeled to separate the support substrate 11 and the sample substrate (sample substrate) 13 (peeling step S6). In this peeling process, at least one of ashing processing, SPM processing, and organic cleaning processing, or a combination thereof is used to form a resist from one main surface 11a side of the support substrate 11 and the bonding surface 13a side of the sample substrate 13. Layer 12 is peeled off. In particular, the SPM process, the organic cleaning process, and the combination process including one of them are preferable because the bonded portion between the sample substrate (sample substrate) 13 and the support substrate 11 can be removed quickly and reliably.

  The ashing process, which is an example of the peeling process S6, includes photo-excited ashing in which a gas such as ozone and oxygen is introduced, light such as ultraviolet rays is irradiated to the gas or wafer, and the photoresist is peeled off by a chemical reaction between the gas and the photoresist. Alternatively, plasma ashing or the like in which oxygen gas is turned into plasma by high frequency and the like, and the photoresist is stripped using the plasma can be used.

Further, the SPM treatment as an example of the peeling step S6 is to remove residues such as photoresist and metal impurities by mixing sulfuric acid and hydrogen peroxide solution and further heating.
Furthermore, the organic cleaning process as an example of the peeling step S6 is to dissolve and remove the photoresist using an organic solvent capable of dissolving the photoresist.

Through the above steps, a processed sample substrate (sample substrate) 13A obtained by performing processing based on a semiconductor process, for example, dry etching, on the sample substrate (sample substrate) 13 can be obtained.
Note that the resist layer 15 on the surface of the sample substrate (sample substrate) 13 is usually removed at the same time by the peeling step S6. Therefore, as shown in FIG. 2D, the sample substrate (sample substrate) 13 is peeled off with only the oxide film 14 attached to the SiC substrate. The remaining oxide film 14 may be removed by, for example, hydrofluoric acid treatment.

  As described above, according to the sample substrate processing method of the present invention, with respect to the sample substrate (sample substrate) 13 having a shape smaller than the substrate shape that the stage (substrate stage) 21 of the vacuum processing apparatus 20 can support, When performing processing based on a semiconductor process, a sample substrate (sample substrate) 13 is attached to a support substrate 11 having a substrate shape that can be supported by a stage (substrate stage) 21 via a resist layer 12 made of photoresist. By doing so, it becomes possible to perform processing (vacuum processing) based on the semiconductor process on the sample substrate (sample substrate) 13 without fouling the vacuum processing apparatus 20.

  In addition, in the sample substrate processing method of the present invention, a photoresist frequently used as a semiconductor process is simply formed between the support substrate 11 and the sample substrate (sample substrate) 13, so that the cost can be reduced with a simple process. A sample substrate (sample substrate) 13 can be attached to the support substrate 11.

  Although one embodiment of the present invention has been described above, this embodiment is presented as an example and is not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 11 ... Support substrate 12 ... Resist layer 13 ... Sample substrate (sample substrate)
20 ... Vacuum processing equipment

Claims (8)

A sample substrate processing method for processing a sample substrate using a vacuum processing apparatus including a substrate stage on which a support substrate is placed,
A resist layer forming step of forming a resist layer by applying a photoresist to one main surface of the support substrate;
An attaching step of attaching the sample substrate to the support substrate through the resist layer;
A placing step of placing the support substrate on which the sample substrate is adhered on the substrate stage;
A sample substrate processing step of processing the sample substrate using the wafer processing apparatus;
A peeling step of peeling the sample substrate from the resist layer;
A method for processing a sample substrate, comprising:   The sample substrate processing method according to claim 1, further comprising a heating step of heating the support substrate on which the sample substrate is bonded between the bonding step and the placing step.   3. The sample substrate processing method according to claim 1, wherein the sample substrate processing step is a step of performing dry etching by irradiating an electron beam or a focused ion beam toward the sample substrate. 4.   The said peeling process peels off the said sample board | substrate from the said support substrate using at least any one among an ashing process, a SPM process, and an organic washing process, The Claim 1 thru | or 3 characterized by the above-mentioned. The processing method of the sample substrate as described.   In the attaching step, using the mark indicating the crystal orientation formed on the support substrate, the crystal orientation of the support substrate is attached so that the crystal orientation of the sample substrate matches. The processing method of the sample substrate as described in any one of Claims 1 thru | or 4.   The sample substrate processing method according to claim 1, wherein the sample substrate is smaller than the support substrate.   The sample substrate processing method according to claim 1, wherein the sample substrate has an indefinite shape. Using a vacuum processing apparatus provided with a substrate stage on which a support substrate is placed, a sample substrate transport method when processing a sample substrate,
A resist layer forming step of forming a resist layer by applying a photoresist to one main surface of the support substrate;
An attaching step of attaching the sample substrate to the support substrate through the resist layer;
A transporting step of transporting the sample substrate in a state where the sample substrate is adhered to the support substrate;
A method for transporting a sample substrate, comprising:

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