JP2005113175A - Doping apparatus and doping method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a doping apparatus capable of suppressing the occurrence of particles produced when being used, enhancing yield, and reducing the number of times of downtime, and to provide a doping method. <P>SOLUTION: The inner wall of a chamber in the doping system is made affinity to doping elements. In the Figure, the wall material of the chamber 101 is formed of CaVO<SB>3</SB>. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a doping apparatus, and more particularly to a doping apparatus that generates plasma by DC arc discharge using a filament.

  In a doping apparatus in a semiconductor process, plasma is mainly generated by DC arc discharge using a filament (mainly tungsten).

  Compared with conventional RF discharge, the plasma generation method using DC arc discharge has a high temperature in the chamber, especially in the vicinity of the electrodes and filaments. Therefore, high melting point metals such as molybdenum (Mo) and stainless steel are often used as the chamber material. It was.

  Particles are generated in the doping process in the doping apparatus composed of these chamber materials, abnormal discharge (hereinafter referred to as arcing) occurs frequently, or these particles adhere to the substrate, resulting in TFT malfunction and yield. There was a problem of decline.

  As a cause of the generation of particles, constituent elements of a gas containing a doping element (hereinafter referred to as doping gas) are deposited on the inner wall of the chamber with the use time of the doping apparatus, and a film deposited on the inner wall of the chamber (hereinafter referred to as a deposited film) is peeled off. There are particles generated by falling and powdery particles generated by vapor phase growth during plasma reaction.

  In particular, particles due to peeling of the deposited film on the inner wall of the chamber near the filament are prominent. When the doping apparatus is used, the filament is energized and heated to about 2000 ° C. in order to generate plasma, and the temperature in the chamber reaches several hundred degrees. At this time, the chamber inner wall in the vicinity of the filament has a higher temperature, so that the expansion of the chamber wall increases. The expanded chamber wall shrinks with decreasing temperature. Then, internal stress is applied to the deposited film on the inner wall of the chamber, and when the internal stress cannot be withstood, the deposited film peels off and becomes particles.

  As a countermeasure against this problem, there is a method of opening the chamber to the atmosphere every time a certain period of use elapses and cleaning the inside of the chamber, but this leads to an increase in downtime of the apparatus.

Accordingly, an ion doping apparatus that can reduce the peeling of the film deposited on the inner wall of the chamber by treating the inner wall of the chamber into irregularities as a countermeasure for the above-described problem is disclosed. (Patent Document 1)

Further, as a method for suppressing the generation of particles, a doping apparatus provided with means for introducing an oxidizing gas such as the atmosphere, H ₂ O, or O ₂ gas when the number of particles starts to increase is disclosed. (Patent Document 2)

Further, a non-plasma dry etching cleaning process using chlorine trifluoride gas (ClF ₃ ) is disclosed as a cleaning method for an ion implantation apparatus. (Patent Document 3)
JP 2002-42717 A JP 2001-332208 A Japanese Patent No. 2821751

However, in Patent Document 1, particles can be suppressed by peeling off the film deposited on the inner wall of the chamber, but generation of powdery particles generated by vapor phase growth during the plasma reaction cannot be effectively prevented. In the above-mentioned patent document 2, when particles start to increase, an oxidizing gas such as air, H ₂ O, or O ₂ gas is introduced to suppress the generation of particles. However, the doping process must be interrupted, and the problem of increasing downtime remains. Further, the cleaning method of Patent Document 3 still has the problem of increasing the downtime.

  Accordingly, an object of the present invention is to provide a doping apparatus and a doping method capable of suppressing the generation of particles generated when using a doping apparatus, improving the yield, and reducing the number of downtimes.

  In order to solve the above problems, as a basic idea of the present invention, by making the inner wall of the chamber of the doping apparatus compatible with the doping gas, powder particles generated by vapor phase growth at the time of plasma reaction can be obtained. Generation of the doping gas constituting element is promoted and the deposition film on the inner wall of the chamber is prevented from being peeled off, so that particles caused by the peeling of the deposition film can also be suppressed.

Examples of materials having an affinity for boron include boric anhydride (B ₂ O ₃ ), boric acid (H ₃ BO ₃ ), SiO _{2 and} other oxide ceramic materials, carbon materials, and the like. Other oxide ceramic materials such as metal oxide, alumina (Al ₂ O ₃ ), calcium vanadate (CaVO ₃ ), zirconia (ZrO ₂ ), beryllia (BeO), titania (TiO ₂ ), zinc monoxide (ZnO), etc. SiO _{2 includes} silicon oxide and quartz, and examples of the carbon material include graphite, diamond, diamond-like carbon, carbon nanotube, and fullerene.

  By forming the chamber wall with these materials or coating the inner wall surface, the generation of particles can be suppressed. In particular, by using a ceramic material for the chamber wall, it is possible to effectively reduce peeling of the deposited film due to a rapid temperature change due to the low thermal conductivity characteristics in addition to the affinity. It is desirable to process the material so that the inner wall of the chamber has a large surface area. Note that the entire inner wall of the chamber does not have to be processed with these materials, and only portions exposed to plasma may be processed with these materials. The chamber material need not be a metal as long as the plasma potential can be kept uniform, and there is no problem with an insulator. Alternatively, the chamber may be a double structure and only the inner chamber wall may be processed with these materials. For example, a vacuum deposition method, a sputtering method, a sublimation method, a PVD method, a coating method, or the like can be given as a coating method, and coating may be performed as a pretreatment for doping.

    Furthermore, for example, by using a mixed gas of boric acid and diborane or a mixed gas of water vapor and diborane as a doping gas during the doping process, it is possible to continuously prevent the generation of particles and reduce the number of downtimes. It is very effective to reduce.

  Note that these materials are not limited to the exemplified materials as long as the materials have an affinity for the constituent elements of the doping gas.

  The present invention is not limited to the arc discharge type of an ion doping apparatus, and may be used for an RF type or an ion implantation apparatus. An ion implantation apparatus is an apparatus for doping ions by separating the mass and charge ratio of ions.

  By using the present invention, it is possible to suppress generation of particles that cause frequent arcing when using a doping apparatus and particles that adhere to the substrate and become dust, thus improving yield and further reducing the number of downtimes. Can reduce and provide high productivity.

(Embodiment 1)
In Embodiment 1, a filament type doping apparatus using CaVO ₃ which is a material having an affinity for a doping gas as a chamber wall material will be described with reference to FIG.

The main configuration of this doping apparatus includes an ion source 101, a drawing chamber 102, a processing chamber 103, a load lock chamber 104, a gas supply system 105, and a vacuum discarding means 106. Here, the extraction chamber 102 is a place where an extraction electrode system 110 for extracting an ion beam from the ion source to the processing chamber is provided, but it is needless to say that the ion source 101 and the extraction chamber 102 may not be separated. The processing chamber 103 is a place where a substrate is held and ions are implanted, and a substrate stage 107 is provided. In the present embodiment, the chamber wall of the ion source 101 is formed of CaVO ₃ .

  The substrate 100 is carried into the substrate stage 107 by the transfer means 108. The ion source 101, the extraction chamber 102, and the processing chamber 103 are exhausted by the vacuum exhaust means 106. Needless to say, the ion source 101, the extraction chamber 102, and the processing chamber 103 may be separately provided to be evacuated. The vacuum exhaust means 106 can be used by appropriately combining a dry pump, a mechanical booster pump, a turbo molecular pump, and the like.

  The ion source 101 includes a gas supply system 105 for supplying a doping gas and a filament 109 for forming plasma. The doping gas does not have to be supplied from the ion source 101 but may be supplied from either the extraction chamber 102 or the processing chamber 103. Further, although the filament 109 by DC arc discharge is used as the plasma generating means, an electrode for capacitively coupled high-frequency discharge may be used.

  As the extraction electrode system 110, an extraction electrode 110a, an acceleration electrode 110b, a suppression electrode 110c, and a ground electrode 110d are provided. A large number of openings are provided in these electrodes, and ions pass through the openings. Ion acceleration is performed by the extraction electrode 110a to which the extraction voltage Vex is applied and the acceleration electrode 110b to which the acceleration voltage Vac is applied, and the suppression electrode 110c to which the suppression voltage Vsb is applied collects ions that diverge and collect the ion flow. The directionality of is raised.

Although the doping gas is PH ₃ , B ₂ H _6, etc., Embodiment 1 will describe a doping apparatus that can particularly reduce particles generated during boron doping using B ₂ H ₆ .

A doping gas diluted with hydrogen or an inert gas to about 1 to 5% is used. In the case of B ₂ H ₆ , BH _x , B ₂ H _x , etc. are generated as ion species. When mass separation is not performed, these ions are accelerated by the extraction electrode system 110 and the processing chamber 103 in which the substrate is installed. Pulled out. Ions are drawn out almost linearly by the four electrodes as an ion flow as shown by arrows in FIG.

  A substrate 100 on which a resist mask pattern is formed is fixed on a substrate stage 107. The substrate stage 107 is generally designed so that it can rotate along an axis parallel to the ion flow. The ion stream accelerated by the extraction electrode system is irradiated onto the rotating substrate 100, and the dose amount becomes uniform.

Although Embodiment 1 shows a configuration in which CaVO ₃ is used only for the chamber wall of the ion source 101, all the chamber walls of the ion source 101, the extraction chamber 102 and the processing chamber 103, only the chamber wall of the extraction chamber 102, and the processing chamber 103. CaVO ₃ may be used as a chamber wall material for only the chamber wall of the ion source 101, only the chamber wall of the ion source 101, only the chamber wall of the extraction chamber 102, or only the chamber wall of the processing chamber 103. Moreover, it is not limited to these, You may use for a load-lock chamber if necessary. Alternatively, the chamber wall may have a double structure, and the inner chamber wall may be made of CaVO ₃ . Furthermore, the inner wall of the chamber may be coated with CaVO ₃ without being used for the chamber wall material itself.

In the first embodiment, any material having an affinity for the doping gas can be used as a chamber wall material or a coating material for the inner wall of the chamber.
For example, boric anhydride, boric acid, SiO ₂ , other oxide ceramic materials, carbon materials, etc. may be used as materials having an affinity for boron. Other oxide ceramic materials include metal oxides, alumina (Al ₂ O ₃ ), calcium vanadate (CaVO ₃ ), zirconia (ZrO ₂ ), beryllia (BeO), titania (TiO ₂ ), and zinc oxide (ZnO). Examples of the SiO ₂ include silicon oxide and quartz, and examples of the carbon material include graphite, diamond, diamond-like carbon, carbon nanotube, and fullerene. Examples of these coating methods include a vacuum deposition method, a sputtering method, a sublimation method, a CVD method, a PVD method, and a coating method.

In Embodiment 1, even if the doping apparatus is used for a long time, the chamber wall is made of CaVO ₃ having an affinity for boron. Therefore, when the TFT is manufactured using this doping apparatus, the operation of the TFT is performed. The generation of particles that cause defects can be reduced, and the number of downtime can be reduced.

  The present invention is not limited to the configuration shown in FIG. 1, and may be used for an ion implantation apparatus, for example.

(Embodiment 2)
In Embodiment 2, a configuration in which a protective member 201 is partially provided on the inner wall of a chamber in an arc discharge doping apparatus will be described with reference to FIG.

  Since the vicinity of the filament becomes very hot, peeling of the deposited film from the inner wall of the chamber in the vicinity of the filament becomes a significant problem. In view of this, a protective member 201 having an affinity for the doping gas is provided on the inner wall of the chamber of the ion source 101 near the filament 109 to try to suppress the generation of particles. This embodiment is particularly effective for suppressing generation of particles due to peeling of the deposited film. The part not shown in the figure may have the same configuration as in FIG. 1 or a doping apparatus having a different configuration. Since the configuration of the second embodiment is partially provided with a protective member, the problem can be easily improved at low cost.

  In Embodiment 2, a doping apparatus capable of reducing peeling of a deposited film when boron doping is performed using diborane as a doping gas will be described. In the vicinity of the filament 109 of the ion source 101, alumina having excellent heat resistance, low thermal conductivity, and low thermal expansion coefficient is used as the protective member 201 having affinity for the doping gas.

  In order to generate plasma, the filament 109 is heated to about 2000 ° C., and the inside of the ion source 101 reaches several hundred ° C. At this time, the inner wall of the chamber near the filament 109 becomes higher in temperature, but by providing the protective member 201, the adhesion with the boron film formed by depositing the doping gas constituent element is improved, and further, due to the rapid thermal change of the inner wall of the chamber. Since internal stress to the boron film accompanying expansion and contraction of the chamber inner wall is weakened, peeling of the boron film can be suppressed. Therefore, it is possible to reduce the generation of particles that cause frequent dusting and arcing on the substrate.

  Here, the diborane of the doping gas and the alumina of the protective member 201 are not limited, and the protective member only needs to be compatible with the doping gas.

  Further, even if the protective member 201 itself has no affinity for the doping gas, the protective member 201 may be coated with a material having an affinity for the doping gas.

  As a typical example, the materials described in Embodiment Mode 1 can be used.

(Embodiment 3)
In the third embodiment, a mixed gas of boric acid gas and diborane gas is used as a doping gas in a doping apparatus in which the chamber wall has a double structure, the outer chamber is made of SUS, and the inner chamber wall 301 made of aluminum is anodized. The doping method used will be described with reference to FIG.

  The doping apparatus of FIG. 3 has a configuration in which the doping apparatus of FIG. 1 is placed sideways (that is, the ion beam is a horizontal beam), and common portions use common reference numerals. In the configuration in which the doping apparatus is placed sideways as in this configuration, the adhesion of particles to the substrate due to the peeling of the deposited film can be further reduced. However, the present invention is not limited to the configuration as shown in FIG. 3, and a configuration in which a doping apparatus is placed vertically as shown in FIG. 1 may be used, or an ion implantation apparatus or the like may be used.

  A mixed gas of boric acid gas and diborane gas as a doping gas is introduced into the ion source 101 from the gas supply system 105. A mixed gas of boric acid gas and diborane gas is diluted with hydrogen gas to about 1 to 5% and used.

  In Embodiment 3, by using a mixed gas of boric acid and diborane as a doping gas, the generation of powder particles generated by vapor phase growth during the plasma reaction is suppressed, and a deposited film that is difficult to peel off is formed on the inner wall of the chamber. Form. Therefore, even if the doping apparatus is used for a long time, the effect of suppressing particles can be continuously maintained, which is very effective in reducing the number of down times.

  Needless to say, Embodiment Mode 3 can be used in combination with Embodiment Modes 1 to 2.

In Example 1, in order to provide a doping apparatus having the structure of the present invention, an example of a procedure for coating the inner wall of the chamber with SiO ₂ by the plasma CVD method will be described below with reference to FIG. To do.

First, the inside of the chamber is evacuated by the evacuation means 106 through the exhaust pipe, and the pressure in the chamber is reduced to 1 × 10 ⁻⁴ Pa. Thereafter, argon gas is introduced into the chamber at a flow rate of 30 sccm by the gas supply system 105, and the filament 109 is heated by energization to maintain the filament temperature at about 2000 ° C. Then, the gas passing near the heated filament 109 is dissociated and plasma is generated. Thereafter, silane gas is used as a source gas, oxygen is used as a reaction gas, and 20 sccm of oxygen is introduced into the chamber from the gas supply system 105 at a flow rate of 200 sccm. Silane gas and oxygen gas may be introduced as a mixed gas, or, of course, a coating gas may be introduced by providing another gas supply system from a location different from the doping gas supply system. Then, the exhaust is adjusted by a valve or the like to keep the inside of the chamber at 5 × 10 ⁻¹ Pa. Here, in order to form a plasma region so that SiO ₂ is deposited on the inner wall of the chamber, the pressure in the chamber is preferably 1 × 10 ⁻¹ to 1 × 10 ¹ Pa. Then, the film is continuously formed for 2 hours to form a SiO ₂ film of about 2 μm.

SiO ₂ has good adhesion to stainless steel, has excellent corrosion resistance, and is also compatible with boron, which is a constituent element of doping gas, so it reduces the generation of particles that cause dust and arcing on the substrate. I can do it.

It should be noted that the inner wall of the chamber may be made compatible with the doping gas constituent elements by plasma CVD using boric acid gas as a pre-doping treatment, as well as coating with SiO ₂ as in Example 1. The material shown in Form 1 can be used as appropriate. Further, the inside of the chamber may be coated not only by the plasma CVD method but also by other coating methods. Examples of other coating methods include vacuum deposition, sputtering, sublimation, PVD, and coating.

  In Embodiment 2, a configuration in which a sputtering apparatus is provided in a doping apparatus will be described with reference to FIG. According to this configuration, a material having affinity for the doping gas can be coated on the inner wall of the chamber by a simple method. The same reference numerals as in FIG. 1 are used for the same parts as in FIG.

  The main configuration of this doping apparatus includes an ion source 101, a sputtering target chamber 501, a drawing chamber 102, a processing chamber 103, a load lock chamber 104, a gas supply system 105, and a vacuum disposal means 106. Here, the extraction chamber 102 is a place where an extraction electrode system 110 for extracting an ion beam from the ion source to the processing chamber is provided, but the ion source 101 and the extraction chamber 102 need not be separated. The processing chamber 103 is a place where a substrate is held and ions are implanted, and a substrate stage 107 is provided. The sputter target chamber is a place where a sputter target is installed for coating.

  The substrate 100 is carried into the substrate stage 107 by the transfer means 108. The ion source 101, the extraction chamber 102, and the processing chamber 103 are exhausted by the vacuum exhaust means 106. Of course, evacuation may be provided separately for the ion source 101, the extraction chamber 102, and the processing chamber 103. The vacuum exhaust means 106 can be used by appropriately combining a dry pump, a mechanical booster pump, a turbo molecular pump, and the like.

  The ion source 101 includes a gas supply system 105 for supplying a doping gas and a filament 109 for forming plasma. The doping gas does not have to be supplied from the ion source 101 but may be supplied from the sputtering target chamber 501, the extraction chamber 102, and the processing chamber 103. Although the filament 109 by DC arc discharge is used as the plasma generating means, a capacitively coupled high frequency discharge electrode may be used.

  As the extraction electrode system 110, an extraction electrode 110a, an acceleration electrode 110b, a suppression electrode 110c, and a ground electrode 110d are provided. A large number of openings are provided in these electrodes, and ions pass through the openings. Ion acceleration is performed by the extraction electrode 110a to which the extraction voltage Vex is applied and the acceleration electrode 110b to which the acceleration voltage Vac is applied, and the suppression electrode 110c to which the suppression voltage Vsb is applied collects ions that diverge and collect the ion flow. The directionality of is raised.

A doping gas diluted with hydrogen or an inert gas to about 1 to 5% is used. In the case of B ₂ H ₆ , BH _x , B ₂ H _x , etc. are generated as ion species. When mass separation is not performed, these ions are accelerated by the extraction electrode system 110 and the processing chamber 103 in which the substrate is installed. Pulled out. Ions are drawn almost linearly by four electrodes as an ion flow as shown by arrows in FIG.

  A substrate 100 on which a resist mask pattern is formed is fixed on a substrate stage 107. The substrate stage 107 is generally designed so that it can rotate along an axis parallel to the ion flow. The ion stream accelerated by the extraction electrode system is irradiated to the rotating substrate 100, and the dose becomes uniform.

  In Example 2, the sputter target chamber 501 is provided, and the inner wall of the ion source 101 can be coated with a material having an affinity for the doping gas constituent element. The coating method will be described below. The target material is conveyed onto the stage by the target material conveying means 502. For example, if an alumina sputtering target disclosed in JP-A-2000-64034 is used as the target, the film formation rate in the alumina chamber can be increased.

  Fix the target on the stage. As a fixing method, a known method can be used. For example, a doping substrate fixing method (Japanese Patent Application No. 2001-133561) disclosed by the present applicant may be used as a sputtering target fixing method.

Then, through an exhaust pipe by the vacuum evacuation means 106, the chamber is evacuated, the pressure was reduced until the chamber to approximately 1.0 × 10- ⁴ Pa, 30sccm of Ar Subsequent gas supply system 105, the O ₂ The chamber is introduced at a flow rate of 0.8 sccm, and the inside of the chamber is maintained at 5 × 10 ⁻¹ by adjusting the vacuum exhaust means. The Ar gas may be provided with a gas supply system different from the doping gas supply system 105, or Ar gas may be supplied from the sputtering target chamber 501.

  When performing sputter deposition, a bias is applied so that the filament side is positive and the stage side on which the target is fixed is negative. Then, the gas is heated by the filament and is discharged and ionized. Since the stage of the sputter target is negatively biased, the ions collide with the target and the sputter target is sputtered, sputtered particles (sputtered atoms, clusters, ions, etc.) are deposited on the inner wall of the chamber, and the inner wall of the chamber is sputter target. Can be coated with materials. In this embodiment, alumina is coated on the inner wall of the chamber.

  In Embodiment 2, the configuration in which the sputtering apparatus is provided in the doping apparatus is shown, but the present invention is not limited to this, and an arc discharge type apparatus or vapor deposition apparatus for forming carbon nanotubes may be provided.

  Through the above process, the inner wall of the chamber can be coated with alumina having an affinity for boron. Therefore, even if the doping apparatus is used for a long time, particles adhere to the substrate and cause frequent occurrence of arcing. Occurrence is suppressed.

  The implantation of an impurity element into a semiconductor using such a doping apparatus is applied to a manufacturing process of an integrated circuit using a semiconductor substrate such as a single crystal silicon wafer or an SOI substrate, and a manufacturing process of a thin film transistor (TFT) formed over a glass substrate. be able to.

  FIG. 5 shows an example of a manufacturing process of a TFT using the doping apparatus of the present invention. First, in FIG. 5A, semiconductor films 702 and 703 which are separated in an island shape from the semiconductor film manufactured in Example 2 over a light-transmitting substrate 700 such as aluminoborosilicate glass or barium borosilicate glass. Form. Further, between the substrate 700 and the semiconductor film, a first insulating film 701 in which one or a plurality of kinds selected from silicon nitride, silicon oxide, and silicon nitride oxide is combined is formed with a thickness of 50 to 200 nm.

Thereafter, as shown in FIG. 5B, a second insulating film 704 is formed with a thickness of 80 nm. The second insulating film 704 is used as a gate insulating film and is formed using a plasma CVD method or a sputtering method. As the second insulating film 704, a silicon oxynitride film formed by adding O ₂ to SiH ₄ and N ₂ O can reduce the fixed charge density in the film and is a preferable material for the gate insulating film. Needless to say, the gate insulating film is not limited to such a silicon oxynitride film, and an insulating film such as a silicon oxide film or a tantalum oxide film may be used as a single layer or a laminated structure.

  A first conductive film for forming a gate electrode is formed over the second insulating film 704. Although there is no limitation in the kind of 1st electrically conductive film, electroconductive materials, such as Al, Ta, Ti, W, Mo, or these alloys are applicable. As the structure of the gate electrode using such a material, a stacked structure of tantalum nitride or titanium nitride and W or a Mo—W alloy, a stacked structure of W and Al, or Cu, or the like can be used. In the case of using Al, a material to which 0.1 to 7% by weight of Ti, Sc, Nd, Si, Cu or the like is added in order to improve heat resistance is used. The first conductive film is formed with a thickness of 300 nm.

  Thereafter, a resist mask 715 is formed to a thickness of 3 μm, and the first conductive film is etched by dry etching to form gate electrodes 705 and 706. Although not shown, a wiring connected to the gate electrode is also formed at the same time.

As shown in FIG. 5C, the mask 715 is left as it is, and phosphorus ions are doped by an ion doping method using the gate electrode as a mask. The ion doping performed in this step uses the mask 715 and the gate electrodes 705 and 706 as masks for the semiconductor films 702 and 703 and has a dose amount of 1 × 10 ¹⁴ to 1 × 10 ¹⁵ / cm ^{2 in} a region outside the gate electrode. N-type semiconductor regions 707 and 708 are formed by doping with phosphorus ions. At this time, if particles are generated, they become dust and adhere to the substrate, causing wiring defects, or frequently causing arcing, which changes the ionization rate, leading to deterioration of transistor characteristics. Thus, by using the doping apparatus of the present invention, the generation of particles can be reduced and the yield can be improved.

  When phosphorus ion doping is completed, the mask 715 is removed by ashing. Ashing is performed by oxygen plasma, and the resist can be peeled off by treatment for 30 to 45 minutes.

Subsequently, as shown in FIG. 5D, a resist mask 709 is formed on one semiconductor film 703, boron ions are doped into the semiconductor film 702, and a dose is 1 × 10 ¹⁴ to 1 × 10 ¹⁵ / cm. ² to, but to be added at a concentration of 1.5 to 3 times than the phosphorus to invert the n-type. At this time, the generation of particles becomes more remarkable due to the high dose, but the generation of particles can be reduced by using the doping apparatus of the present invention.

  After doping with boron ions, the mask 709 is removed by ashing. Ashing is similarly performed by oxygen plasma, and the resist can be peeled off by treatment for 30 to 45 minutes.

  Thereafter, as shown in FIG. 5E, a third insulating film 711 made of a silicon oxynitride film or a silicon nitride film is formed to a thickness of 50 nm by plasma CVD.

  Then, heat treatment is performed to recover and activate the crystallinity of the n-type and p-type semiconductor regions. In addition to the furnace annealing furnace, the heat treatment can be performed by methods such as rapid thermal annealing and laser annealing.

  The fourth insulating film 712 illustrated in FIG. 5F is formed using a silicon oxide film or silicon oxynitride. Alternatively, the surface may be planarized by forming with an organic insulating material such as polyimide or acrylic.

  Next, a contact hole reaching the impurity region of each semiconductor film from the surface of the fourth insulating film 712 is formed, and wiring is formed using Al, Ti, Ta, or the like. In FIG. 5F, reference numerals 713 and 714 denote source lines or drain electrodes. Thus, an n-channel TFT and a p-channel TFT can be formed. Although each TFT is shown here as a single unit, a CMOS circuit, NMOS circuit, or PMOS circuit can be formed using these TFTs.

  As described above with reference to FIG. 5, there are a plurality of steps in the TFT manufacturing process. In order to increase the yield, the occurrence of defects must be reduced in each step. As described above, by using the doping apparatus of the present invention in the doping process, generation of particles in the chamber can be reduced, and defective wiring and deterioration of transistor characteristics can be suppressed, thereby improving yield. . Furthermore, the downtime due to the chamber opening can be reduced and the productivity can be improved. Here, the TFT manufacturing process is shown as an example, but the present invention can also be applied to a semiconductor integrated circuit manufacturing process using a planar process.

  The doping apparatus of the present invention is used for any impurity doping as well as impurity doping to a semiconductor substrate for the purpose of manufacturing an LSI and impurity doping to a semiconductor substrate for a driving circuit of a liquid crystal display device. Can do.

The figure which shows an example of the doping apparatus provided with the structure of this invention The figure which expanded the ion source of an example of the doping apparatus provided with the structure of this invention The figure which shows an example of the doping apparatus provided with the structure of this invention The figure which shows an example of the doping apparatus provided with the structure of this invention Diagram explaining the manufacturing process of TFT

Claims (10)

In a doping apparatus that ionizes and injects a doping element into a semiconductor film,
A doping apparatus, wherein an inner wall of a chamber is made of a material having affinity for a doping gas. In a doping apparatus that ionizes and injects a doping element into a semiconductor film,
A doping apparatus, wherein an inner wall of a chamber is coated with a material having affinity for a doping gas. In a doping apparatus that ionizes and injects a doping element into a semiconductor film,
A doping apparatus comprising a protective member made of a material having affinity for a doping gas on an inner wall of a chamber. In a doping apparatus that ionizes and injects a doping element into a semiconductor film,
A doping apparatus comprising means for coating the inside of a chamber with a material having affinity for a doping gas. 5. A doping apparatus according to claim 1, wherein the doping element is boron. 6. The doping apparatus according to claim 1, wherein the material having affinity is boric anhydride, boric acid, oxide ceramic, one of carbon materials, or a mixture thereof. Using a doping apparatus that ionizes and injects a doping element into a semiconductor film,
A doping method characterized by using a doping gas having affinity for boron. 8. The doping method according to claim 7, wherein the doping gas is a mixed gas of boric acid and diborane, a mixed gas of water vapor and diborane, or a mixed gas thereof. Before performing doping using a doping apparatus that ionizes and injects a doping element into a semiconductor film,
Coating the inner wall of the chamber with a film that has an affinity for the constituent elements of the doping gas,
A doping method comprising performing doping. 10. The doping method according to claim 9, wherein the affinity film is one of boric anhydride, boric acid, an oxide ceramic, a carbon material, or a mixture thereof.

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