KR20070024881A - Ion implantation apparatus and ion implantation process - Google Patents

Abstract

An ion implanting apparatus is provided to avoid variation of the ratio of ions to be implanted and prevent a difference of sheet resistance between substrates by including a catalyst electrode for converting gas into radicals and a magnetic filter for preventing radicals from being implanted into the substrate. A catalyst electrode(300) is formed in an active layer formed on a substrate(270) by using photoresist as a mask, converting the gas generated in an ion implantation process into radicals. The catalyst electrode is positioned over the substrate. A magnetic filter(310) prevents the radicals from being transferred to the substrate. The catalyst electrode and the magnetic filter are installed in a process chamber(180) in which an ion implantation process is carried out. A pump(290) exhausts the radicals to the outside.

Description

ION IMPLANTATION APPARATUS AND ION IMPLANTATION PROCESS}

1 is a plan view showing an ion implantation apparatus according to an embodiment of the present invention.

2 is a cross-sectional view showing an ion source portion of an ion implantation apparatus according to an embodiment of the present invention.

3 is a cross-sectional view showing a permanent magnet array of an ion source unit according to an embodiment of the present invention.

4 is a cross-sectional view showing a mass spectrometer of an ion implantation apparatus according to an embodiment of the present invention.

5A to 5D are cross-sectional views illustrating a step of discharging a gas generated in an ion implantation process according to an exemplary embodiment of the present invention.

<Code Description of Main Parts of Drawing>

10: ion implantation device 20: ion source unit

30: arc chamber 40: extraction electrode

50: suppression electrode 60: ground electrode

70 permanent magnet array 100 mass spectrometer

110: outer wall 120: inner wall

130: beamline unit 140: vertical scan unit

150: horizontal scan unit 155: ion beam accelerator

160: load lock chamber 170: unload lock chamber

180: process chamber 190: first cassette

200: second cassette 210: first rod arm

220: second rod arm 230: third rod arm

240: fourth rod arm 250: road shuttle

260: unload shuttle 270: substrate

280: table 290: pump

300: catalytic electrode 310: magnet filter

The present invention relates to an ion implantation apparatus and an ion implantation process, and more particularly, to an ion implantation apparatus and an ion implantation process for releasing a gas generated during the ion implantation process.

In general, in the manufacturing process of the polysilicon liquid crystal display, the ion implantation process is a process of evenly injecting ions to a desired depth of the active layer deposited on the substrate by applying high energy to the implanted ions.

Through the ion implantation process, an LED (Lightly Doped Drain) region is formed between the source region, the drain region, and the channel region to prevent off current. In general, the LED area is deposited with metal as a mask, and then n + or p + ions are implanted into the source and drain areas, and then the metal used as the mask is stripped to form n- or p- ions in the area where the LED is to be formed. It is formed by injection. However, this process is complicated because it requires the deposition, etching and stripping of the metal used as the mask.

To solve this problem, a method of using a photoresist instead of a metal as a mask has been developed and applied. The use of the photoresist as a mask has the advantage of avoiding the above-described complicated process, but there is a possibility that the photoresist may be deformed or damaged depending on the acceleration voltage and the dose amount during ion implantation.

When ions are injected in excess (eg, 1E15 atom / cm 2 or more), the photoresist cannot handle the heat generated during ion implantation and deformation occurs. That is, the edge portion of the photoresist is dried or thinned. Since the n + or p + ions are implanted into the region where the LED is to be formed through the edge portion of the deformed photoresist, the LED region of the predetermined section cannot be formed. For this reason, the problem that the off current of a polysilicon liquid crystal display device becomes higher than normal value arises.

In addition, when ions are injected in an excessive amount, the ions colliding with the photoresist breaks the chemical bond between carbon and hydrogen constituting the photoresist, and gases such as hydrogen and carbon monoxide are generated. Hydrogen in these gases causes ion beam neutralization by charge exchange with the ion beam to be injected and remaining in the process chamber and ion source portion of the ion implantation device. As a result, the proportion of ions to be implanted actually changes and sheet resistance variations between substrates occur.

Therefore, there is a need for a method of effectively releasing gases generated in the ion implantation process.

The technical problem to be achieved by the present invention relates to an ion implantation device and an ion implantation process for releasing a gas generated during the ion implantation process.

In order to achieve the above object, the present invention is characterized in that the ion is located on the substrate and using a photoresist as a mask comprising a catalytic electrode for converting the gas generated during ion implantation into the active layer formed on the substrate into radicals Provide an injection device.

A magnet filter may be further included to prevent the radicals from moving toward the substrate. In addition, the magnet filter may be formed between the catalyst electrode and the substrate.

The catalyst electrode and the magnet filter may be formed in a process chamber in which an ion implantation process is performed. It may further include a pump for discharging the radicals to the outside.

The surface of the catalyst electrode may be coated with platinum and the gas may be hydrogen generated from the photoresist.

In order to achieve the above object, the present invention provides a method of forming a photoresist in a predetermined section of a substrate, implanting ions into the substrate using the photoresist, and generating a radical using a catalyst electrode. It provides an ion implantation process comprising the step of converting.

The method may further include using a magnetic filter to prevent the radicals from moving toward the substrate. The catalyst electrode and the magnet filter may be formed in a process chamber in which the ion implantation process is performed.

The method may further include discharging the radicals to the outside by using a pump. The method may further include heating the catalyst electrode to a predetermined temperature so that the radicals are easily formed.

The converting of the gas generated during the ion injection into the radical using the catalyst electrode may be a step of converting the gas into the radical by platinum coated on the surface of the catalyst electrode. The step of converting the gas generated during the ion implantation into the radical using the catalyst electrode may be a step of converting hydrogen into hydrogen radicals.

Other objects and features of the present invention in addition to the above object will become apparent from the description of the embodiments with reference to the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a plan view showing an ion implantation apparatus according to an embodiment of the present invention.

Referring to FIG. 1, an ion implantation apparatus 10 according to an exemplary embodiment of the present invention includes an ion source unit 20 for generating an ion beam, a mass spectrometer 100 for separating only ions to be injected from the ion beam, and a substrate 270. A load lock chamber 160 to be loaded, an unload lock chamber 170 to which the substrate 270 is unloaded, and a process chamber 180 to which an ion implantation process is performed are provided.

As shown in FIG. 2, the ion source unit 20 includes an arc chamber 30 for generating ions, a permanent magnet array 70 for forming a magnetic field perpendicular to the moving direction of the ions, and an ion in the arc chamber 30. It is configured sequentially in the outgoing direction and includes an extraction electrode 40 and the suppression electrode 50 and the ground electrode 60 to generate an ion beam by extracting only cations among the ions generated in the arc chamber 30.

The arc chamber 30 receives a raw material gas from the gas supply unit 80. The gas supply unit 80 supplies the raw material gas filled in the gas cylinder 85 to the arc chamber 30 at a constant pressure through the gas pressure regulating device 90. The source gas collides with the hot electrons emitted by heating through the high frequency induction current of the coil 75 and is separated into electrons and ions.

At this time, when energy between 0 KeV and -90 KeV is applied between the arc chamber 30 and the suppression electrode 50, cations among the ions generated in the arc chamber 30 pass through the permanent magnet array 70 to prevent the formation of the suppression electrode 50. Will be pulled out in the direction. Permanent magnet array 70, as shown in Figure 3, the magnets of the north pole and the south pole are arranged in a row and improve the elimination of unwanted ions and uniformity of the ions.

Energy of 0 KeV to -40 KeV is applied to the suppression electrode 50 so that electrons drawn together with the cation do not pass. The cations passing through the extraction electrode 40 and the suppression electrode 50 are guided to the ground electrode 60 and guided to the mass spectrometer 100 in the form of an ion beam.

As shown in FIG. 4, the mass spectrometer 100 separates ions having a desired mass from the ion beams that have passed through the ion source unit 20. To this end, a bent cylindrical mass spectrometer 100 is formed with a magnetic field (Magnetostatic field). As a result, heavy ions collide with the outer wall 110 of the mass spectrometer 100, and light ions collide with the inner wall 120 of the mass spectrometer 100 and have an intermediate mass. Only ions to be passed through the mass spectrometer 100. The intensity of the static magnetic field can be adjusted to select the desired ion species.

The ion beam passing through the mass spectrometer 100 passes through the ion beam accelerator 155 to have a predetermined energy (for example, 30 KeV to 200 KeV or more) and is vertically scanned with the horizontal scan unit 150 of the beamline unit 130. Passed through the unit 140 is led to the process chamber 180.

The load lock chamber 160 is located on one side of the process chamber 180. The substrate 270 stacked on the first cassette 190 is transferred to the load lock chamber 160. To this end, the substrate 270 stacked on the first cassette 190 is transported to be grasped by the first load arm 210 through the load shuttle 250 and is loaded by the first lock arm 210 by the first load arm 210. 160).

When the substrate 270 is transferred to the load lock chamber 160, the high pressure in the load lock chamber 160 to make the same high vacuum state as the process chamber 180 before the substrate 270 is transferred to the process chamber 180 This is carried out. Thereafter, the third load arm 230 in the process chamber 180 mounts the substrate 270 in the load lock chamber 160 to the table 280 in the process chamber 180.

The unload lock chamber 170 is located on one side of the process chamber 180 symmetrically with the position of the load lock chamber 160 with respect to the process chamber 180. The substrate 270 after the ion implantation process is transferred to the unload lock chamber 170 through the fourth load arm 240. At this time, in order to expose the substrate 270 to the outside atmosphere, the inside of the unload lock chamber 170 is elevated to atmospheric pressure. Subsequently, the substrate 270 is stacked in the second cassette 200 through the second load arm 220 and the unload shuttle 260.

In the process chamber 180 located on one side of the beamline unit 130, an ion implantation process is performed by the ion beam passing through the beamline unit 130. To this end, a table 280 in which the substrate 270 is loaded is provided in the process chamber 180.

In the process chamber 180, the catalyst electrode 300 and the magnet filter 310 which are sequentially configured in the traveling direction of the ion beam are formed. The catalyst electrode 300 is formed of a surface of a disk-shaped stainless steel having a predetermined thickness (for example, 2 mm to 3 mm), and a platinum Pt having a thickness of a predetermined thickness (for example, 0.3 μm) is ion plated or the like. It is formed by coating. The catalyst electrode 300 converts the gas generated in the photoresist into radicals.

The magnet filter 310 forms an electromagnetic field to prevent the radicals generated by the catalyst electrode 300 from moving in the direction of the substrate. The radicals thus generated are discharged to the outside by the pump 290 positioned below the process chamber 180.

5A to 5D are cross-sectional views illustrating a step of discharging a gas generated in an ion implantation process according to an exemplary embodiment of the present invention.

The ion implantation apparatus 10 of the present invention converts various gases such as hydrogen, carbon monoxide, and water vapor generated from the photoresist 320 into radicals and discharges them to the outside. However, hereinafter, an example is described in which hydrogen (H 2) is converted into hydrogen radical (H ·) and discharged.

The table 280 in the process chamber 180 erects the substrate 270 vertically as shown in FIG. 5A when the substrate 270 is seated thereon. Thereafter, the ion beam passing through the beamline unit 130 is injected into the substrate 270 to proceed with the ion implantation process. In the ion implantation process, since the photoresist 320 is used as a mask as described above, hydrogen (H 2) is generated and remains in the process chamber 180.

This hydrogen (H2) is converted to hydrogen radical (H ·) as shown in FIG. 5B by platinum coated on the surface of the catalyst electrode (300). At this time, the catalyst electrode 300 can be heated to a predetermined temperature (for example, 150 ° C.) in order to easily form hydrogen radicals (H ·). In addition, a catalyst electrode coated with another catalyst capable of converting hydrogen (H 2) into hydrogen radical (H ·) may be used instead of platinum.

On the other hand, since the generated hydrogen radicals (H ·) can be injected onto the substrate 270, as shown in FIG. 5C, a magnet filter 310 is provided between the catalyst electrode 300 and the substrate 270. The magnet filter 310 prevents hydrogen radicals (H ·) from moving in the direction of the substrate 270 using an electromagnetic field generated from the magnetic filter 310.

Then, as shown in FIG. 5D, the pump 290 is operated to discharge the hydrogen radical H · to the outside of the process chamber 180. At this time, the pump 290 is a vacuum pump using mechanical compression, a turbomolecular pump (Turbomolecular Pump, which can exhaust the hydrogen radical (H ·) by applying a dynamic force to the hydrogen radical (H ·) through a high speed rotation, TMP) can be used. In addition, as the pump 290, a cryopump (Cryo Pump) for condensing and discharging gas on an extremely cooled surface may be used.

The ion implantation apparatus of the present invention includes a catalyst electrode for converting a gas into a radical, and a magnet filter positioned between the catalyst electrode and the substrate to prevent radicals from being injected into the substrate.

Due to this ion implantation device, charge exchange does not occur between the ions and the gas of the ion beam in the process chamber, so that the ratio of the ions to be actually implanted does not change and the sheet resistance variation does not occur between the substrates. In addition, the stability of the ion implantation process can be improved, the periodic maintenance cycle of the ion implantation device can be lengthened, and the productivity can be improved.

In the detailed description of the present invention described above with reference to the preferred embodiment of the present invention, those skilled in the art or those skilled in the art having ordinary knowledge of the present invention described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the spirit and scope of the art.

Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (14)

Located above the substrate And a catalytic electrode for converting a gas generated during ion implantation into a radical by using a photoresist as a mask to the active layer formed on the substrate. The method of claim 1, An ion implantation device, characterized in that it further comprises a magnetic filter to prevent the radicals from moving in the direction of the substrate. The method of claim 2, The magnet filter is ion implantation device, characterized in that formed between the catalyst electrode and the substrate. The method of claim 2, And the catalyst electrode and the magnet filter are formed in a process chamber through which an ion implantation process is performed. The method of claim 2, Ion injection device further comprises a pump for discharging the radicals to the outside. The method of claim 1, The surface of the catalyst electrode is ion implantation device, characterized in that coated with platinum. The method according to any one of claims 1 to 6, And the gas is hydrogen generated from the photoresist. Forming a photoresist on a predetermined portion of the substrate; Implanting ions into the substrate using the photoresist; Ion implantation process comprising the step of converting the gas generated during the ion implantation into a radical using a catalyst electrode. The method of claim 8, And a step of preventing the radicals from moving in the direction of the substrate using a magnetic filter. The method of claim 9, And the catalyst electrode and the magnet filter are formed in a process chamber through which the ion implantation process is performed. The method of claim 9, Ion injection process further comprising the step of discharging the radical to the outside using a pump. The method of claim 8, The ion implantation process further comprises the step of heating the catalyst electrode to a predetermined temperature so that the radicals are easily formed. The method of claim 8, The step of converting the gas generated during the ion implantation into the radical using the catalyst electrode Ion implantation process, characterized in that for converting the gas into the radical by the platinum coated on the surface of the catalyst electrode. The method according to any one of claims 8 to 13, The step of converting the gas generated during the ion implantation into the radical using the catalyst electrode An ion implantation process, characterized in that the step of converting hydrogen into hydrogen radicals.

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