KR100576194B1 - Buried insulating film manufacturing apparatus and manufacturing method using large output pulse RF plasma - Google Patents

Abstract

The present invention provides a device and manufacturing an investment insulating film using a high-output pulsed RF plasma to manufacture a silicon-on-insulator (SOI) substrate having a high yield using a high-output pulsed RF plasma instead of the conventional continuous plasma It is about a method. The sample is placed in a vacuum chamber and a working gas is injected into the vacuum chamber. RF pulses are supplied into the vacuum chamber to generate a high density plasma from the used gas. A negative high voltage pulse is applied to the sample so that the generated plasma ions collide with the sample and accelerate toward the sample with sufficient ion energy to inject ions into the sample surface. At this time, RF pulse generation and negative high voltage pulse generation are synchronized. Then, the sample is annealed to form an insulating film.

RF pulse, plasma, wafer, investment insulating film, annealing

Description

Equipment and manufacturing method for investment insulating film using high output pulse RF plasma {DEVICE AND METHOD OF FABRICATING BURIED INSULATOR LAYER USING HIGH-POWER PULSED RF PLASMA}

1 is a schematic view showing a buried insulating film manufacturing apparatus using a high-output pulsed RF plasma according to the present invention,

2A and 2B are waveform diagrams of RF output voltages and voltages applied to a target in the investment insulating film manufacturing apparatus using the high-output pulsed RF plasma according to the present invention, respectively.

Figure 3 is a transmission electron microscope cross-sectional photograph of the SOI structure obtained by the buried insulating film manufacturing apparatus using a high power pulsed RF plasma according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10: vacuum chamber

12: vacuum pump

14: gas injection device

16: antenna

18: pulsed RF power supply

20: matching network

22: sample support

24: high voltage pulse generator

26: trigger pulse generator

28: plasma measuring device

30: permanent magnet

w: wafer

TECHNICAL FIELD The present invention relates to semiconductor device manufacturing, and more particularly, to an apparatus and a method for forming a buried insulating film on a silicon substrate.

With the development of semiconductor technology, not only the development of process technology but also the development of silicon wafer, which is a core material, has emerged as an important task for manufacturing next-generation semiconductor devices such as device performance improvement and low power consumption. In particular, a silicon-on-insulator (SOI) wafer with a SiO ₂ layer called buried oxide (BOX) between silicon single crystal structures is emerging as an alternative to overcome the limitations of existing wafers.

Conventional methods used to form such an SOI structure include a wafer bonding method in which an oxide film is formed on two silicon wafers to be bonded to form a buried oxide film, and an ion beam is accelerated and injected into the silicon with high energy. And the Separation by IMplanted OXygen (SIMOX) method of forming a buried oxide film through. However, the wafer bonding method is disadvantageous in that the bonding process is cumbersome and time consuming, and the smox method has a long process time and a complicated device due to the low beam current of the ion beam accelerator for injecting the ion beam at a high dose. There are disadvantages that are expensive.

Plasma ion implantation techniques using plasma and high voltage pulses disclosed in US Pat. No. 4,764,394 and Korean Patent Registration No. 137704 may be applied to the fabrication of SOI substrates. Due to the characteristics of plasma ion implantation technology that uses a periodic pulse having a duty cycle of less than 1%, an ion collision phenomenon occurs in the sample with energy corresponding to the plasma floating potential between pulses and pulses. There is a problem that does not occur physical and chemical reactions.

The present invention is to solve the problems of the prior art, an object of the present invention is to use a high-output pulsed RF plasma instead of the conventional continuous plasma to produce a high-output pulsed RF having a high yield of the SOI substrate An apparatus for manufacturing an investment insulating film using plasma is provided.

Another object of the present invention is to provide a method of manufacturing an investment insulating film for manufacturing an SOI substrate having a high yield through a high temperature annealing process after plasma ion implantation using the device for manufacturing an investment insulating film using the high-output pulsed RF plasma.

An investment insulating film manufacturing apparatus using a high output pulsed RF plasma according to the present invention for achieving the above object is a vacuum tank; A support for supporting a sample in the vacuum chamber; A high voltage pulse generator for applying a sample by generating a negative high voltage pulse; An antenna for forming a pulsed plasma from gas injected into the vacuum chamber; A pulsed RF power device connected to the antenna for supplying an RF pulse; And a trigger pulse generator connected between the high voltage pulse generator and the pulsed RF power device.

In order to achieve the above object, a method of manufacturing an investment insulating film using a high power pulsed RF plasma according to the present invention includes placing a sample in a vacuum chamber; Injecting use gas into the vacuum chamber; Supplying an RF pulse into the vacuum chamber to generate a high density plasma from the used gas; Injecting ions by applying a negative high-voltage pulse to the sample such that the generated plasma ions collide with the sample and are accelerated toward the sample with sufficient ion energy to inject ions into the sample surface; Synchronizing the RF pulse generation with a negative high voltage pulse generation; And annealing the sample to form an insulating film.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

1 is a block diagram schematically illustrating an apparatus for manufacturing an investment insulating film using a high output pulse RF (Radio Frequency) plasma according to the present invention.

As shown in the drawing, a sample support 22 for supporting a wafer w as a sample extends from the bottom surface of the vacuum chamber 10 inside the vacuum chamber 10, and the vacuum chamber 10 is provided from the gas injection device 14. An antenna 16 for generating pulsed plasma by using the used gas injected into the inside of 10 is provided above the wafer w. The vacuum chamber 10 is electrically grounded and the degree of vacuum is maintained by the vacuum pump 12.

The generated plasma ions impinge on the wafer w and generate a negative high voltage pulse on the wafer w so as to be accelerated toward the wafer w with sufficient ion energy to inject ions onto the surface of the wafer w. The high voltage pulse generator 24 is applied to the sample support 22 for installation. The antenna 16 is connected to a pulsed RF power device 18 for supplying an RF pulse to generate a plasma, and a matching network for electrically matching them between the antenna 16 and the pulsed RF power device 18. 20 is installed. A trigger pulse generator 26 is connected between the high voltage pulse generator 24 and the pulsed RF power device 18 to move at the same time by synchronizing them.

Since the plasma generated in the vacuum chamber 10 is confined in the vacuum chamber 10 by a magnetic field formed by a plurality of permanent magnets 30 mounted around the outer surface of the vacuum chamber 10, the plasma is maintained at a high density and uniformity. In addition, the temperature and density of the plasma can be appropriately adjusted by measuring by the plasma measuring apparatus 28, for example, a Langmuir probe. As the plasma source gas injected into the vacuum chamber 10, oxygen, nitrogen, or ammonia may be used, but is not limited thereto. In addition, the antenna 16 for generating plasma may be mounted outside the vacuum chamber 10 via a predetermined insulator between the vacuum chamber 10.

Hereinafter, a manufacturing method using a buried insulation film manufacturing apparatus using a high output pulsed RF plasma according to the present invention configured as described above will be described.

The buried insulating film manufacturing method according to the present invention comprises the steps of placing a sample in a vacuum chamber; Injecting use gas into the vacuum chamber; Supplying an RF pulse into the vacuum chamber to generate a high density plasma from the used gas; Injecting ions by applying a negative high-voltage pulse to the sample such that the generated plasma ions collide with the sample and are accelerated toward the sample with sufficient ion energy to inject ions into the sample surface; Synchronizing the RF pulse generation with a negative high voltage pulse generation; And annealing the sample to form an insulating film.

Although not limited thereto, one embodiment will be described in detail. As shown in (a) of FIG. 2, the maximum measurement value of the pulsed RF output voltage is about 1.2 kW, and when it is expressed as RF power, it is about 14 kW. And the average RF power corresponds to 200W. The pressure in the vacuum chamber 10 was 1 mTorr of oxygen. A pulse width of 600 Hz and a pulse frequency of 25 Hz were applied to the antenna 16 inside the vacuum chamber 10 to generate a pulsed plasma. At this time, the density of the plasma measured using the plasma measuring apparatus 28 was approximately 2 × 10 ¹¹ / cm ³ , and when the RF power was increased, a high density plasma having an ionization rate of 1% or more could be generated. .

Based on the above embodiment, the RF pulses generated in the high power pulsed RF power device 18 for manufacturing the SOI substrate are pulse widths of 10 kHz to 1000 kHz, pulse frequencies of 10 kHz to 10 kHz and maximum pulse powers of 1 kHz to 100. The values of 수 may be used, and the RF frequency uses 13.56 MHz, but other frequencies may be used.

As shown in Fig. 2B, the negative high voltage pulse applied to the target, that is, the wafer w, is 10 Hz to 100 Hz, the pulse width is 10 Hz to 500 Hz, and the pulse frequency is 10 Hz to 10 Use values of ㎑ This high voltage pulse is synchronized with the pulsed plasma by the trigger pulse generator 26.

In the plasma ion implantation step as described above, for example, the oxygen plasma is mostly composed of O ₂ ⁺ ions, so that the O ₂ ⁺ or O ⁺ ions are 90% or more. It is preferred to form.

In order to recover the lattice damaged by ion implantation during the plasma implantation step, the temperature of the wafer (w) during ion implantation should be controlled to about 550 ° C. to 650 ° C., using a pulsed RF plasma according to the present invention. Due to the high dose of ¹⁶ / cm 2 to 1 × 10 ¹⁸ / cm 2, the damage of the lattice can be repaired without the use of a separate wafer heater, and the wafer throughput can be increased due to the short injection time.

After the plasma ion implantation step, annealing is performed in an argon atmosphere in which 0.1% to 5.0% of oxygen is added at a high temperature of 1200 ° C to 1400 ° C to form an insulating film of the implanted ions. At this time, in order to prevent the surface of silicon from being damaged during the annealing process, it is preferable to form a protective film made of a silicon oxide film or a silicon nitride film on the silicon surface before the annealing step.

3 is a transmission electron microscope cross-sectional photograph of the SOI structure obtained by the buried insulating film manufacturing apparatus and method using a large output pulsed RF plasma according to the present invention.

After implanting oxygen plasma ions generated through the pulsed RF power device 18 into the p-type silicon substrate 40 at 65 kHz, depositing a 200 nm silicon nitride film 46 and then adding 0.5% oxygen to argon. Annealing was conducted at 1350 ° C. for 30 minutes. As shown in FIG. 3, the SOI structure including the buried oxide film 42 and the upper silicon film 44 is formed on the silicon substrate 40. The buried oxide film 42 may be formed by implantation energy, ion amount, and heat treatment conditions. The thickness of the upper silicon film 44 may vary.

The present invention is not limited to the above embodiments, and various modifications may be made by those skilled in the art without departing from the gist of the present invention as claimed in the claims.

As described above in detail, according to the buried insulating film manufacturing apparatus and manufacturing method using a large-output pulsed RF plasma according to the present invention, since the plasma is formed only during the ion implantation is applied to the average RF power lower than the conventional continuous plasma Even though it has a very high plasma density, a large amount of ions can be injected even in a short time, and the plasma sheath according to the high density is very small, and thus ion implantation can be uniformly applied to the wafer.

Claims (9)

Vacuum chamber; A support for supporting a sample in the vacuum chamber; A high voltage pulse generator for generating a negative high voltage pulse to apply the sample; An antenna for forming a pulsed plasma from gas injected into the vacuum chamber; A pulsed RF power device connected to the antenna for supplying a radio frequency (RF) pulse; And An investment insulating film manufacturing apparatus using a high power pulsed RF plasma, characterized in that consisting of a trigger pulse generator is connected between the high voltage pulse generator and the pulsed RF power device. In the manufacturing method of the investment insulating film using a high output pulse RF plasma, Placing the sample in a vacuum chamber; Injecting use gas into the vacuum chamber; Supplying an RF pulse into the vacuum chamber to generate a high density plasma from the use gas; Injecting ions by applying a negative high-voltage pulse to the sample such that the generated plasma ions collide with the sample and are accelerated toward the sample with sufficient ion energy to inject ions into the sample surface; Synchronizing the RF pulse generation with a negative high voltage pulse generation; And An annealing method for manufacturing an investment insulating film using a high-output pulsed RF plasma, characterized in that it comprises the step of annealing the sample to form an insulating film. The method of claim 2, wherein the RF pulse has a pulse width of 10 Hz to 1000 Hz, a pulse frequency of 10 Hz to 10 Hz, and a maximum pulse power of 1 Hz to 100 Hz. . The buried insulating film using the high output pulsed RF plasma according to claim 2, wherein the negative high voltage pulse has a frequency of 10 Hz to 100 Hz, a pulse width of 10 Hz to 500 Hz, and a pulse frequency of 10 Hz to 10 Hz. Manufacturing method. The method of claim 2, wherein in the step of implanting the ion while maintaining the temperature of the sample at 550 ℃ ~ 650 ℃ ion implantation with a dose of 1 × 10 ¹⁶ / ㎠ ~ 1 × 10 ¹⁸ / ㎠ Method of manufacturing an investment insulating film using a pulsed RF plasma. The method of claim 2, wherein the annealing is performed at a temperature of 1200 ° C. to 1400 ° C. in an argon atmosphere in which 0.1% to 5.0% of oxygen is added. . The method of claim 2, further comprising forming a protective film on the surface of the sample before the annealing. The method of claim 7, wherein the protective film is a silicon oxide film. The method of claim 7, wherein the protective film is a silicon nitride film.

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