JP3490669B2 - Nonvolatile material etching method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for processing a sample substrate using a plasma etching process.

[0002]

2. Description of the Related Art Samples such as semiconductor devices and magnetic heads are subjected to wet etching using a chemical solution or dry etching using gas plasma. Conventionally, as materials to be etched, Si, SiO ₂ , Al, Ti
Inorganic materials such as N and SiN and hydrocarbon resins such as photoresists have been widely used. Since the reaction product of the etching in the plasma atmosphere is volatile under the reduced pressure atmosphere and the reaction product does not adhere to the side wall of the material to be etched during etching, vertical processing could be easily performed. However, in recent years, as the application range of etching has expanded, such as magnetic heads, memory devices using ferroelectric thin films, and memory devices using the magnetic spin effect, NiF
e alloy layer, CoNiFe alloy layer, Cu layer, Al ₂ O
₃ layers, CoFe layer, Ru layer, Pt layer, PtMn layer, BS
There is an increasing need for etching materials such as T layers and PZT layers whose reaction products during etching are non-volatile.

[0003]

When this kind of material is etched, the reaction product of the reactive gas and the material to be etched is non-volatile, so that it adheres to the side wall of the material to be etched and the etching shape becomes vertical. There was a problem that it could not be maintained and spreads in a taper shape. It is an object of the present invention to provide an etching method capable of making a sidewall shape vertical after an etching process in etching a material to be etched whose reaction product is non-volatile.

[0004]

When the material to be etched described above is subjected to plasma etching treatment with a gas containing chlorine, for example, the reaction product generated is non-volatile, so that it adheres to the sidewall of the material to be etched during etching. And prevents vertical etching. However, since the main component of the reaction product is chloride, it is water-soluble. For example, Ni, Fe,
Chlorides such as Co, Cu, Ru, Pt, Pb and Zn are non-volatile in vacuum and at the same time water-soluble. Therefore, if the whole etching process step is divided into several steps for such a material, and the etching process and the process of washing away the water-soluble reaction product by washing and drying are performed in each step, the etching process is performed. A non-volatile material that tends to have a tapered shape can be processed more vertically.

In other words, taking the case where the material to be etched is Si as an example, the reaction product SiCl ₂ of Si is volatile and does not adhere to new side wall surfaces formed one after another during etching. Is possible. However, when the reaction product is non-volatile, the reaction product adheres to the side wall formed during the etching, resulting in a tapered shape. At this time, vertical processing is possible if the attached reaction products can be removed one after another. In other words, if the reaction product is non-volatile, if the reaction product can be removed in water by performing the washing process as often as possible,
The verticality of processing is improved.

The present invention specifically provides the following method and apparatus. The present invention provides a non-volatile material film formed on a substrate through a mask formed on the material,
A first step of performing a dry etching process for a certain period of time in a plasma etching process chamber using a reactive gas;
In the second step, the reaction products attached to the side wall of the film to be etched and the side wall of the mask material are washed and stripped with a liquid, and heated and dried. The first step and the second step are performed. A method for treating a non-volatile material is provided, which is repeated at least a plurality of times until the etching depth reaches a target value.

The present invention further provides a method for treating a non-volatile material, wherein the non-volatile material is a NiFe alloy or a NiFeCo alloy.

The present invention further provides that the reactive gases are Cl ₂ , B.
Provided is a method for treating a non-volatile material using at least one gas of Cl ₃ , Ar, and O ₂ or a combination of these gases.

According to the present invention, the second step of cleaning with the liquid is: (A) a step of cleaning with pure water, (B) a step of cleaning with an alkaline liquid, and then a step of cleaning with water, (C).
Washing with acidic liquid and then with water, (D)
Provided is a method of treating a non-volatile material, which comprises one or two or more of a step of washing with hydrofluoric nitric acid and then with water, and a step of washing with (E) a neutral detergent and then with water. To do. The present invention further provides a method for treating a non-volatile material, wherein the temperature of the liquid in the liquid cleaning in the second step is controlled.

The present invention further provides (A) Pt layer, (B) Cu layer, (C) Al ₂ O as another non-volatile material film.
₃ layers, (D) CoFe layer, (E) Ru layer, (F) PtM
Provided is a method for treating a non-volatile material, which is an n layer, a (G) BST layer, and a (H) PZT layer.

The present invention further relates to a sample processing apparatus for etching a sample laminated on a substrate, a cassette stand on which a cassette loaded with the sample substrate is placed, and a gas plasma is supplied to generate a gas plasma on the substrate. An etching treatment device for etching the non-volatile material formed in
Equipped with a cleaning / drying device for cleaning / peeling and drying the reaction products deposited by the etching process, a transporting device for transporting the sample substrate between the etching processing device, the cleaning / drying device, and the cassette table, and the target etching depth. (EN) Provided is a non-volatile material etching device having a function capable of repeating etching for a certain period of time in an etching processing chamber and side wall peeling by a cleaning / drying device until the value is reached, a plurality of times.

The present invention further provides, in the above etching apparatus, an atmospheric loader, a vacuum transfer chamber having a vacuum transfer robot therein, and an unload and load lock for connecting the atmospheric loader and the vacuum transfer chamber to send a sample substrate. A chamber, the vacuum transfer chamber is connected to the etching processing chamber of the etching processing device, and the atmosphere loader is connected to a cleaning cup and a hot plate of the cleaning / drying device. A non-volatile material etching apparatus is provided.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below with reference to the drawings.

FIG. 1 shows the shape of a non-volatile material (here, a NiFe film) during etching in the prior art,
FIG. 2 shows a shape at the time of etching when the present invention is carried out. A non-volatile material 110 is formed on the substrate 100. According to FIG. 1, as the etching of the non-volatile material progresses, the reaction products adhere to the side wall of the material to be etched generated during processing (D2, D3). At the side wall, the deposition rate is higher than the etch rate, so that the deposition of reaction products proceeds. The deposited reaction products serve as a mask for etching treatment and hinder the etching of the bottom portion, so that the shape gradually becomes a tapered shape and vertical processing into a desired shape cannot be performed (D5).

In the present invention shown in FIG. 2, as a first step, the substrate that has been subjected to etching treatment for a certain period of time is carried out from the etching treatment chamber to a cleaning / drying apparatus, and as a second step, the reaction product attached to the side wall is washed with water. Then, it is peeled off (D2, D2 '). Then, as a third step, the etching process is performed again for a certain time, and in the fourth step, the second
The reaction product is peeled off as in the step (D3, D
3 '). Thus, if the etching and the peeling of the reaction product are repeated at least a plurality of times, the verticality of the processed shape after the etching treatment is improved.

Even when the present invention is implemented, the processed shape is tapered during each etching step. This is because the deposition of reaction products occurs at the same time as etching as in the case of the prior art. However, after a certain etching step, if the material to be etched is exposed and the material to be etched is exposed and etching is started again, the angle formed between the etching surface and the horizontal surface is small even among the sidewalls of the material to be etched that are tapered. The sidewalls are selectively etched. This is because, as shown in FIG. 3, the side wall having a smaller angle between the etching surface and the horizontal surface has a higher etching rate. However, on the other hand, the deposition rate of reaction products is constant regardless of the inclination of the side wall,
The etching rate becomes more dominant than the deposition rate of the reaction product as the side wall has a smaller angle between the etching surface and the horizontal plane (FIG. 4).

As a result, the side wall surface which is tapered in the etching process in the previous step is also more vertical because the etching in the vertical direction of the taper portion is additionally performed in the etching process in the next step after the completion of washing with water. Processing is possible.

Next, the structure of the etching apparatus that specifically realizes the present invention will be described. FIG. 5 shows the configuration of the device of the present invention. In the figure, the sample substrate processing apparatus includes an etching processing apparatus 1, a vacuum transfer device 2, a load lock chamber 3, an unload lock chamber 4, an atmospheric transfer device 5, a cleaning / drying device 6, an atmospheric loader 7, a cassette 8 and a cassette. The table 9 is provided.

As the etching processing apparatus 1, an apparatus for etching a sample substrate under reduced pressure using plasma is used. Incidentally, as the plasma etching process,
An inductively coupled plasma etching apparatus, a helicon type plasma etching apparatus, a dual frequency excitation parallel plate type plasma etching apparatus, a microwave type plasma etching apparatus, etc. are adopted.

In FIG. 5 , the cleaning / drying device 6 includes a cleaning cup 21, a hot plate 22, and a transfer device 23.
Equipped with. A spinning wet processing device is used for washing with water. In the spinning wet processing apparatus for cleaning, the post-processed sample substrate is subjected to, for example, a spin cleaning treatment with water, or a chemical solution and water in that order, for example, a spinning cleaning treatment. In this case, the chemical solution is appropriately selected depending on the substance to be removed from the post-processed sample substrate.
Further, as the processing atmosphere, an inert gas atmosphere such as nitrogen gas or an air atmosphere is adopted. Further, after the wet treatment, a drying treatment such as draining is carried out in this state.

As the drying processing apparatus, the wet-processed sample substrate in the wet-processing apparatus is dried, for example, an apparatus for heating and drying the wet-processed sample substrate, and a drying gas for the wet-processed sample substrate. A device for spraying and drying is used. A nitrogen gas atmosphere or an air atmosphere is adopted as the processing atmosphere.

The vacuum transfer device 2 is an etching processing device 1.
Processing station (not shown) and load lock chamber 3,
It has a function of transporting the processed sample substrate to and from the unload lock chamber 4. The atmosphere transfer means 5 has a function of transferring the processed sample substrate between the load lock chamber 3, the unload lock chamber 4 and the cleaning / drying device 6. Carrier 2
3 has a function of transporting the wet-processed sample substrate between the processing station of the wet processing apparatus and the processing station (not shown) of the drying processing apparatus. As the sample substrate transfer device, a known transfer means, for example, a sample substrate scoop for holding the sample substrate from the back surface thereof by an arm that is mechanically, electrically, or magnetically rotated or reciprocally moved. For holding the tool and sample substrate at the outer peripheral edge of the sample substrate gripping tool and sample substrate, for example, an electromagnetic carrier, a sample substrate suction tool for vacuum chucking the arm carrier device, drive roller and driven roller A belt transport device around which an endless belt is wound, a device that transports a sample substrate by a gas blowing force, or the like is adopted. When the etching processing apparatus 1 is an apparatus that processes a sample substrate using plasma under reduced pressure, the vacuum transfer apparatus 2 is provided so that the processed sample substrate can be transferred under reduced pressure and air pressure without exposing it to the atmosphere. There is.

An atmosphere transfer device 5 is provided for transferring the sample substrate from the unload lock chamber 4 to the drying device 6 and for transferring the dried sample substrate to, for example, the collecting cassette 8. The cassette 8 and the cassette table 9 are placed.

When the etching processing apparatus 1 is, for example, an apparatus for processing a sample substrate using plasma under reduced pressure, the sample substrate processing atmosphere of the etching processing apparatus 1 and the sample substrate processed by the etching processing apparatus 1 are The space for transporting to the etching processing apparatus 1 and the space for transporting the processed sample substrate can be communicated with and cut off from each other. A space in which the sample substrate is transferred, a sample substrate wet processing atmosphere of the wet processing apparatus, a space in which the wet processed sample substrate is transferred,
The sample substrate dry processing atmosphere of the dry processing apparatus and the space in which the dry processed sample substrate is transported may be in a state of maintaining communication, or may be capable of communicating and interrupting each.

A processing station (not shown) is provided in the sample substrate processing atmosphere of the etching processing apparatus 1. When the etching processing apparatus 1 is an apparatus that processes a sample substrate under reduced pressure using plasma, the processing station is the sample table 12. One or more sample substrates can be installed on the sample table 12.

In the case where continuous etching is performed on a plurality of laminated films and the step of removing the adhering film adhering to the etching side wall by liquid cleaning after each etching step is performed, the sample substrate from the hot plate is It will be sent to the load lock chamber again without returning to the cassette.

[0027]

As described above, according to the present invention, it is possible to control the taper angle of the side wall after etching in the etching of the non-etched film in which the reaction product is nonvolatile,
It is possible to obtain a vertical processing shape, which was difficult with the conventional technology.

[Brief description of drawings]

FIG. 1 is a diagram showing a shape of a conventional non-volatile material during etching.

FIG. 2 is a diagram showing a shape of a nonvolatile material during etching when the present invention is carried out.

FIG. 3 is a diagram showing a relationship between an etching rate and an angle formed by the etching surface and a horizontal surface.

FIG. 4 is a diagram showing a relationship between an etching rate and a deposition rate, and an angle formed by an etching surface and a horizontal surface.

FIG. 5 is a plan view showing an etching apparatus that is an embodiment of the present invention.

[Explanation of symbols]

1 Etching processing equipment 2 Vacuum transfer device 3 Road lock room 4 unload lock room 5 Atmosphere carrier 6 Cleaning / drying equipment 7 Atmosphere loader 8 cassettes 9 cassette stands 11 Etching chamber 12 sample table 21 wash cup 22 hot plate 23 Conveyor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI H01L 21/306 H01L 21/302 F 21/3065 21/306 S 21/3213 J 21/88 D (72) Inventor Ken Yoshioka Yamaguchi Higashi-Toyoi 794, Oita, Kudamatsu-shi, Japan Incorporated Hitachi Ltd., Kasado Plant (72) Inventor Takashi Sato Yamaguchi Prefecture 794 Higashi-Toyoi, Higamatsu-Ken, Hitachi Techno Engineering Co., Ltd. (72) Inventor Kanai Saburo Yamaguchi Kumamatsu City, Higashi-Toyoi 794, Ltd. Hitachi Ltd., Kasado Plant (56) References JP-A-11-162950 (JP, A) JP-A-9-237821 (JP, A) JP-A-8-181126 (JP , A) JP-A-8-124901 (JP, A) JP-A-7-335570 (JP, A) JP-A-2-301010 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) C23F 1/00-4/04

Claims (8)

(57) [Claims] 1. A non-volatile material film formed on a substrate,
A first step of performing a dry etching process for a certain period of time in a plasma etching process chamber using a reactive gas through a mask formed on the material, and a sidewall of a film to be etched and a sidewall of a mask material in the first step The second step consists of cleaning and peeling the reaction product attached to the substrate with a liquid, and heating and drying the substrate.
A method for etching a non-volatile material, characterized in that the first step and the second step are repeated at least a plurality of times until the etching depth reaches a target value. 2. The non-volatile material according to claim 1, wherein the non-volatile material is Ni.
A method for etching a non-volatile material, which is an Fe alloy or a NiFeCo alloy. 3. The reactive gas according to claim 1, wherein the reactive gas is C.
A method for etching a non-volatile material, which uses at least one gas selected from the group consisting of l ₂ , BCl ₃ , Ar, and O ₂ or a combination of these gases. 4. The cleaning according to claim 1, wherein the liquid cleaning in the second step includes: (A) cleaning with pure water, (B) cleaning with alkaline liquid, and then cleaning with water, (C) Any one of a step of washing with an acidic liquid and then with water, (D) a step of washing with hydrofluoric nitric acid, a step of washing with water, and a step of washing with (E) a neutral detergent and then with water, or A method for etching a non-volatile material, which is any two or more. 5. The method for etching a non-volatile material according to claim 1, wherein the temperature of the liquid used in the liquid cleaning in the second step is controlled. 6. The non-volatile material film according to claim 2, wherein (A) Pt layer, (B) Cu layer, (C) Al ₂ O ₃ layer, (D) CoFe layer (E) Ru layer, (F) PtMn layer, (G) BST layer, (H) PZT layer, and a method for etching a non-volatile material. 7. A sample processing apparatus for etching a sample stacked on a substrate, wherein a cassette table on which a cassette loaded with the sample substrate is placed, and a plasma forming gas is supplied to generate a gas plasma to form on the substrate. Etching device for etching the non-volatile material, a cleaning / drying device for cleaning and drying the non-volatile material layer, the substrate, the mask, and the reaction product deposited by the etching process with a liquid, the etching processing device and the cleaning Equipped with a drying device and a transfer device that transfers the sample substrate between the cassette bases, etching is performed in the etching chamber for a certain period of time and side wall peeling is performed multiple times in the cleaning / drying device until the etching depth reaches the target value. An etching device for non-volatile materials, which has a function capable of being repeated. 8. The atmospheric loader, the vacuum transfer chamber having a vacuum transfer robot therein, and the unload and load lock chambers for connecting the atmospheric loader and the vacuum transfer chamber to transfer a sample substrate. A sample characterized in that the etching processing chamber of the etching processing device is connected to the vacuum transfer chamber, and the cleaning cup and hot plate of the cleaning / drying device are connected to the atmospheric loader. Substrate processing equipment.