JP2010177426A - Etching method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an etching method for suppressing influence of heat to a workpiece and reducing a use amount of etching liquid. <P>SOLUTION: The etching method includes a liquid arranging process for arranging etching liquid Q which receives irradiation of light and is chemically activated on the workpiece (substrate S) and a light irradiation process for irradiating an irradiation region R of an interface F between the workpiece and etching liquid Q with light L. In the liquid arranging process, etching liquid Q is selectively arranged on an etching place on the workpiece. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an etching method.

  A glass substrate used for a semiconductor substrate or a display device constituting a semiconductor device has a multilayer wiring formed in a fine region. In recent years, the miniaturization and multilayering of wiring have been further advanced, and in accordance with this, a technique for finely etching a semiconductor substrate or a glass substrate is required. As such an etching processing technique, for example, processing using an etching mask is widely known.

  In recent years, a technique that does not use an etching mask is also known. As such a maskless technology, for example, by using excited active species generated by plasma discharge under a pressure near atmospheric pressure, various surfaces of the object to be processed can be obtained at low cost without requiring vacuum equipment. Plasma processing techniques that can be processed are known.

  As a plasma processing technique, for example, a gas discharge is directly generated between the electrode and the object to be processed, and a direct discharge method in which the gas is directly exposed to the generated plasma and a plasma is generated by a gas discharge between a pair of electrodes, An indirect discharge method is known in which an object to be processed is exposed to excited active species generated thereby.

However, when the object to be processed is processed by plasma, the object to be processed may be thermally damaged by the plasma.
Therefore, in Japanese Patent Application No. 2008-293375, a proposal for suppressing the influence of heat on the object to be processed is made.

  In Japanese Patent Application No. 2008-293375, an etching solution that is scientifically activated upon irradiation of light is placed on the object to be processed, and light that activates the etching solution is irradiated to the interface between the object to be processed and the etching solution. ing. The object to be processed is etched by activating the etching solution by light irradiation, and the object to be processed can be etched only by a chemical reaction. Therefore, the influence of heat on the object to be processed can be suppressed as compared with the case of irradiating plasma without a mask.

JP 2007-148402 A

  However, in Japanese Patent Application No. 2008-293375, there is a problem that a large amount of the etching solution is used because the object to be processed is immersed in the etching solution or applied to the entire etching surface of the object to be processed. Reducing the amount of etching solution used is strongly demanded from the viewpoint of cost reduction and environmental considerations.

  Therefore, the present invention provides an etching method capable of suppressing the influence of heat on the object to be processed and reducing the amount of etching solution used.

  In order to solve the above-described problems, the etching method of the present invention includes a liquid disposing step of disposing an etching liquid on the object to be chemically activated by irradiation with light, the object to be processed, and the etching. A light irradiation step of irradiating the irradiation region of the interface with the liquid with the light, wherein in the liquid arrangement step, the etching liquid is selectively arranged at an etching location on the object to be processed. .

According to the present invention, the etching solution is chemically activated by irradiating the etching solution with light, and radicals and ions are generated. The object to be processed is etched by the generated radicals and ions reacting with the object to be processed. As described above, the object to be processed can be etched only by a chemical reaction, so that the influence of heat on the object to be processed can be suppressed as compared with the case where plasma is irradiated.
In addition, by selectively disposing an etching solution in an etching portion that is a region where the processing object is etched to form a removal portion, the etching solution is applied to the entire surface of the processing object or the processing object is Compared with the case of immersion in an etching solution, the amount of etching solution used can be significantly reduced.

  The etching method of the present invention is characterized in that, in the liquid disposing step, the etching liquid is disposed at the etching location by an ink jet method.

  According to the present invention, a small amount of an etching solution can be accurately and rapidly disposed at an etching portion of an object to be processed.

  Further, the etching method of the present invention has a liquid-proof treatment step for preventing the etching solution from being placed at a place other than the etching place of the object to be processed before the liquid placement step. To do.

  According to the present invention, it becomes possible to arrange | position an etching liquid only to an etching location, and the usage-amount of an etching liquid can be reduced more.

  The etching method of the present invention is characterized in that, in the light irradiation step, the light reaches the interface by transmitting the object to be processed.

  ADVANTAGE OF THE INVENTION According to this invention, light can be irradiated to the etching liquid from the to-be-processed object side of the interface of an etching liquid and a to-be-processed object. Therefore, it is possible to suppress the diffusion of the activated portion of the etching solution as much as possible. Thereby, even if it is a narrow area | region on a to-be-processed object, it can etch with high precision.

  The etching method of the present invention is characterized in that the etchant contains at least one of a fluorine-based inert liquid, hydrofluoroether, and hexafluorobenzene.

  According to the present invention, since the substance that is easily activated upon irradiation with light is used as the etching solution, the object to be processed can be easily and reliably processed.

  The etching method of the present invention is characterized in that, in the liquid-proof treatment step, a bank portion is formed around the etched portion of the object to be processed.

  ADVANTAGE OF THE INVENTION According to this invention, an etching liquid can be stored inside a bank part and it can prevent that the etching liquid arrange | positioned in an etching location flows out to the outer side of an etching location.

  The etching method of the present invention is characterized in that, in the liquid-proof treatment step, a liquid-repellent treatment is performed around the etched portion of the object to be processed.

  According to the present invention, even if the etching solution arranged at the etching location tries to flow out to the outside of the etching solution, it is repelled by the object to be treated having been subjected to the liquid repellent treatment and returned to the inside of the etching location. Therefore, it can prevent that the etching liquid arrange | positioned at an etching location flows out outside an etching location.

It is the schematic which shows the structure of the etching apparatus which concerns on embodiment of this invention. Process drawing which shows the etching operation | movement using the etching apparatus which concerns on this embodiment. The process drawing. The process drawing. The process drawing.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a configuration of an etching apparatus 1 according to the present embodiment.
As shown in FIG. 1, the etching apparatus 1 includes a stage 2, a light source 3, an etchant supply unit 4, and a control unit 5. The etching apparatus 1 is an apparatus that locally processes a substrate S as an object to be processed by etching. As the substrate S, for example, a substrate whose main component is silicon or glass can be used.

The etching apparatus 1 etches the substrate S using the etching solution Q. As the etchant Q, a material that is chemically activated by photoexcitation, such as a fluorine-based inert liquid, hydrofluoroether, and hexafluorobenzene, can be used. Of course, materials other than those listed here may be used. The etching solution Q used in the present embodiment is preferably chemically inert when it is not irradiated with light.
The stage 2 includes a window portion 2 a for placing the substrate S and exposing the substrate S to the light source 3.

The light source 3 emits light that chemically activates the etching solution Q. The light source 3 is arranged so that the light emitting part 3a faces the window part 2a. The light source 3 is provided to be movable along the formation surface of the window portion 2a. As the light source 3, for example, a KrF excimer laser light source that emits light with a wavelength of 248 nm, an ArF excimer laser light source, a YAG laser light source, an F ₂ laser light source, a mercury lamp that emits ultraviolet rays such as g-line and i-line, A light source such as an Xe ₂ excimer lamp that emits light having a wavelength of 172 nm can be suitably used. In the present embodiment, light having a wavelength that can be transmitted through the substrate S is selected as light emitted from the light source 3. An optimal light source is selected and used in accordance with the type of etching solution Q, the type of substrate S, and the like.

The etchant supply unit 4 is a droplet discharge head of a droplet discharge device that discharges droplets of an etchant by, for example, an inkjet method. The etching solution supply unit 4 is provided so as to be movable to an arbitrary position on the substrate S, and discharges a droplet of the etching solution onto the substrate S from a nozzle provided facing the substrate S.
The control unit 5 comprehensively controls various operations of the etching apparatus 1 such as the operation of the light source 3 and the etching solution supply unit 4.

Next, a method for etching the substrate S using the etching apparatus 1 will be described.
2 to 10 are process diagrams showing a process of etching the substrate S.
Hereinafter, a case where etching is performed on the upper surface Sa in the drawing of the substrate S will be described. Further, the surface Sa is expressed as “etching surface Sa”.

  First, as shown in FIG. 2, the substrate S is placed on the stage 2, and the substrate S is exposed to the light source 3 through the window 2 a of the stage 2. After the substrate S is placed and positioned on the stage 2, the control unit 5 moves the etching solution supply unit 4 and the light source 3 to a position facing the etching portion of the substrate S. As a result, the region where the light emitted from the light source 3 is irradiated onto the surface of the substrate S (irradiation region R) overlaps with the etched portion of the substrate S.

(Liquid placement process)
Next, as shown in FIG. 3, a droplet of the etching solution Q is ejected by the etching solution supply unit 4 to selectively dispose the etching solution Q at an etching location on the substrate S. By this operation, the etching solution Q is disposed on the etching surface Sa of the substrate S, and an interface F is formed between the etching solution Q and the substrate S.

(Light irradiation process)
Next, as shown in FIG. 4, the control unit 5 causes the light emitting unit 3 a to irradiate the window 2 a with the light L. The light L passes through the window portion 2a and the substrate S, and irradiates a part (or the whole) of the irradiation region R of the interface F between the substrate S and the etching solution Q. In the irradiation region R of the interface F that has been irradiated with the light L, the etching solution Q is chemically activated to form an activated portion Qa. In the activated portion Qa, the molecules constituting the etching solution Q exist in a state where they are changed to radicals, ions, and the like by photoexcitation. These radicals and ions undergo a chemical reaction with the substrate S, and as a result of the chemical reaction, the reaction portion of the substrate S is removed and a removal portion Sb is formed as shown in FIG.

  Thus, according to the present embodiment, the substrate S is etched by irradiating the etchant Q with light and chemically activating the etchant Q. Thus, since the substrate S can be etched only by a chemical reaction, the influence of heat on the substrate S can be suppressed as compared with the case where plasma is irradiated.

  In addition, by selectively disposing the etching solution Q in an etching portion that is a region where the removal portion Sb is formed by etching the substrate S, the etching solution Q may be applied to the entire surface of the substrate S or the substrate S Compared with the case of immersing in the etching solution Q, the amount of the etching solution Q used can be significantly reduced. Further, by disposing the etching solution Q at the etching site of the substrate S by the ink jet method, the extremely small amount of the etching solution Q can be accurately and rapidly disposed at the etching site of the substrate S. In addition, since a substance that is easily activated by irradiation with the light L is used as the etching solution Q, the substrate S can be processed easily and reliably.

  In the light irradiation step, the light L reaches the interface F between the substrate S and the etching solution Q by transmitting the substrate S. As a result, the etching liquid Q can be irradiated with light from the substrate S side of the interface F. Therefore, it is possible to suppress the diffusion of the activated portion Qa of the etching solution Q as much as possible. Thereby, even a narrow region on the substrate S can be etched with high accuracy.

In addition, since the periphery of the activated portion Qa in the etching solution Q is a liquid, the mean free path of radicals and ions generated by the activation can be kept low. As a result, diffusion of the activated portion Qa is suppressed. For this reason, the activation part Qa is pinpointed in the etching solution Q by irradiation with the light L, and the substrate S is etched with high accuracy. Further, by selectively disposing the etching liquid Q at the etching location of the substrate S, unnecessary portions are prevented from being etched, and etching can be performed with higher accuracy.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the etching solution supply unit is not limited to the droplet discharge head of the droplet discharge device, and a dispenser or the like may be used.

  Further, in the liquid disposing step, a droplet of the etching liquid may be discharged by the etching liquid supply unit, and an etching liquid pattern corresponding to the pattern of the etching portion may be drawn on the substrate. And a removal part may be formed so that the pattern of the said etching liquid may be traced by moving a light source along the pattern of the said etching liquid in a light irradiation process. At this time, the etching solution supply unit and the light source may be moved simultaneously. Further, the etching solution supply unit and the light source may be moved in a state of facing each other with the etching portion of the substrate interposed therebetween. Alternatively, the etching solution supply unit may draw an etching solution pattern on the substrate, and after the etching solution on the substrate is stabilized, the light source may be moved so as to follow the etching solution pattern.

Moreover, you may perform the liquid-proof process which prevents that etching liquid is arrange | positioned in areas other than the etching location of a board | substrate before a liquid arrangement | positioning process (liquid-proof process).
Specifically, when the etching solution uses a fluorine-based etching material, a bank-like bank portion can be formed around the etching portion. Thereby, it is possible to prevent the etching solution from flowing out of the etching portion. The bank portion can be formed by, for example, applying a bank material on a substrate and using a photolithography method, an etching method, or the like.

When the etching solution does not use a fluorine-based etching material, a lyophilic process may be performed on the etched portion of the substrate surface, and a liquid repellent treatment may be performed on a region other than the etched portion, such as around the etched portion. . Thereby, the etching solution disposed in a region other than the etching location can be repelled to concentrate the etching solution on the etching location of the substrate.
By carrying out such a liquid-proof treatment process before the liquid arrangement process, it becomes possible to arrange the etching liquid only in the etching location, and the amount of etching liquid used can be further reduced.

Moreover, a liquid arrangement | positioning process may be implemented in airtight containers, such as a chamber, and the pressure inside a chamber may be made into a pressure higher than an air pressure. Thereby, evaporation of the etching solution arranged on the substrate can be prevented. Alternatively, the atmosphere near the substrate surface may be saturated with the solvent vapor of the etching solution. Thereby, evaporation of the etching solution arranged on the substrate can be prevented.
A planar light source that irradiates the entire substrate can be used as the light source. This makes it possible to etch a desired pattern without moving the light source.

F interface, Q etching solution, L light, R irradiation area, S substrate (object to be processed)

Claims (7)

A liquid placement step of placing an etching solution on the object to be chemically activated by the irradiation of light;
A light irradiation step of irradiating the irradiation region of the interface between the object to be processed and the etching solution with the light;
Including
In the liquid disposing step, the etching liquid is selectively disposed at an etching location on the object to be processed. The etching method according to claim 1, wherein in the liquid placement step, the etchant is placed at the etching location by an ink jet method. The liquid-proofing process which prevents that the said etching liquid is arrange | positioned in places other than the said etching location of the said to-be-processed object before the said liquid arrangement | positioning process is characterized by the above-mentioned. The etching method as described. The etching method according to any one of claims 1 to 3, wherein, in the light irradiation step, the light reaches the interface by transmitting the object to be processed. The etching method according to any one of claims 1 to 4, wherein the etching solution includes at least one of a fluorine-based inert liquid, hydrofluoroether, and hexafluorobenzene. 5. The etching method according to claim 4, wherein in the liquid-proof treatment step, a bank portion is formed around the etching portion of the object to be processed. 5. The etching method according to claim 4, wherein in the liquid-proof treatment step, a liquid repellent treatment is performed around the etched portion of the object to be treated.

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