JP2003332255A - Doping processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device suitable for processing a large area substrate in a doping device where plasma (ion) is generated, an ion flow is formed by accelerating it with a high voltage, the substrate is irradiated with the ion flow and the substrate is irradiated with a linear laser beam. <P>SOLUTION: A material to be doped is moved in a direction which is almost vertical to a long length direction of an ion flow cross section and the material is doped. In a doping chamber, the substrate is irradiated with the linear laser beam. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a doping apparatus and a doping processing method used when manufacturing a semiconductor integrated circuit or the like. In particular, the present invention relates to an ion doping apparatus and a doping processing method having a preferable structure for processing a large area substrate. For example, a semiconductor material partially or wholly composed of an amorphous component, or a substantially intrinsic polycrystalline semiconductor material is irradiated with an ion beam to add impurities to the semiconductor material. is there.

[0002]

2. Description of the Related Art In the fabrication of a semiconductor integrated circuit or the like, when an N-type or P-type impurity region is formed in a semiconductor, an impurity (N-type impurity / P-type impurity) exhibiting N-type or P-type conductivity type is formed. ) A method of irradiating and implanting ions by accelerating ions with a high voltage is known. In particular, a method of separating the mass and charge ratio of ions is called an ion implantation method, and is widely used when manufacturing a semiconductor integrated circuit.

In addition to the above, a method is known in which plasma having N / P type impurities is generated, ions in the plasma are accelerated by a high voltage, and the ions are injected into the semiconductor as an ion flow. This method is called an ion doping method or a plasma doping method.

The structure of the doping apparatus by the ion doping method is simpler than that of the doping apparatus by the ion implantation method. For example, when boron is implanted as a P-type impurity, plasma is generated by a gas such as diborane (B ₂ H ₆ ) which is a boron compound by RF discharge or another method, and a high voltage is applied to the plasma. Ions having boron are extracted and irradiated into the semiconductor. Since a gas phase discharge is performed to generate plasma, the degree of vacuum in the doping apparatus is relatively high.

At present, an ion doping apparatus is often used to uniformly add impurities to a substrate having a relatively large area. This is because the ion doping apparatus does not perform mass separation and a large-area ion beam can be obtained relatively easily. On the other hand, since the ion implanter needs to perform mass separation, it is difficult to increase the beam area while maintaining the beam uniformity. Therefore, the ion implanter is not suitable for a large area substrate.

[0006] In recent years, active researches have been made on lowering the temperature of semiconductor device processes. The main reason for this is that it is necessary to form a semiconductor element on an inexpensive insulating substrate such as glass. In addition, there are demands for miniaturization of elements and multilayering of elements.

An insulating substrate made of glass or the like has various advantages such as better workability than a quartz substrate which has been conventionally used in a high temperature process, easy enlargement of a large area, and low cost. However, it is also a fact that technical difficulties must be overcome, such as the need to develop a device having properties different from those of the conventional high temperature process, as the area of the substrate is increased.

In the production of an active matrix type liquid crystal display or the like which requires the processing of a large area substrate,
The ion implantation method is disadvantageous in this respect, and research and development have been carried out on the ion doping method for the purpose of compensating for its drawbacks.

[0009]

The outline of a conventional ion doping apparatus is shown in FIGS. 1 and 2. FIG. 1 mainly shows an outline of an ion source and an ion accelerator. Also,
FIG. 2 shows the structure of the entire ion doping apparatus. First,
It will be described with reference to FIG. Ions are generated in the plasma space 4.

That is, by applying high frequency power between the electrode 3 and the mesh electrode 6 by the high frequency power supply 1 and the matching box 2, plasma is generated in the depressurized plasma space 4. Hydrogen or the like is introduced into the atmosphere in the initial stage of plasma generation, and after the plasma is stabilized, diborane or phosphine (PH ₃ ) as a doping gas is introduced.

The electrode 3 and the outer wall of the chamber (the same potential as the mesh electrode 6) are insulated by the insulator 5. The extraction electrode 10 and the extraction power source 8 are used for extracting the ion flow from the plasma thus generated. The ion flow thus extracted is shaped by the suppression electrode 11 and the suppression power source 9,
The required energy is accelerated by the acceleration electrode 12 and the acceleration power supply 7.

Next, FIG. 2A will be described. Ion doping equipment is roughly divided into ion source / accelerator 1.
3, doping chamber 15, power supply device 14, gas box 1
9 and an exhaust device 20. In FIG. 2, the ion source / accelerator shown in FIG. 1 is placed horizontally. That is, FIG.
Then, the ion flow flows from left to right (in FIG. 1, from top to bottom). The power supply device 14 is a collection of power supplies mainly used for ion generation / acceleration, and includes the high frequency power supply 1, the matching box 2, the acceleration power supply 7, the extraction power supply 8 and the suppression power supply 9 of FIG.

A substrate holder 17 is provided in the doping chamber 15, and a material 16 to be doped is placed thereon.
Substrate holders are generally designed to be rotatable along an axis parallel to the ion stream. The ion source / accelerator 13 and the doping chamber 15 are exhausted by the exhaust device 20. Of course, the ion source / accelerator 13 and the doping chamber 15 may be evacuated by independent evacuators.

The doping gas is sent from the gas box 19 to the doping chamber 15 via the gas line 18. In the apparatus of FIG. 2, the gas supply port is provided between the ion source / accelerator 13 and the material 16 to be doped, but it may be provided near the plasma space 4 of the ion source. The doping gas is generally diluted with hydrogen before use.

In the conventional ion doping apparatus, the area of the substrate (material to be doped) that can be processed is equal to or smaller than the cross-sectional area of the plasma space 4 in the ion source 13. This is the condition required by doping uniformity. FIG. 2B shows a state of a cross section perpendicular to the ion flow. That is, the ion source / accelerator 13 has a size of L ₁ and L ₂ , but the doping chamber 15 and the material 17 to be doped are small enough to be accommodated therein. Then, L ₁ and L ₂ are about the same size.

Therefore, it is required that the plasma space 4 becomes larger as the substrate becomes larger. Moreover, the plasma is required to be two-dimensionally uniform. However, it is difficult to make the plasma space infinitely large. This is because the generation of plasma is not uniform. This is mainly because the mean free path of the molecules is sufficiently small compared to the cross section of the plasma space. For this reason, the length of one side of the plasma space is set to 0.
It is difficult to set it to 6 m or more.

[0017]

According to the present invention, the cross section of the ion flow is linear or rectangular, and the material to be doped is perpendicular to the long direction of the ion flow (that is, the short direction) during the doping. It is characterized by moving. By doing so, the plasma only needs to be uniform in the longitudinal direction, and a large-area substrate can be processed. Only the longitudinal uniformity of the plasma becomes a problem,
The reason why the two-dimensional uniformity does not matter is that, when focusing on an arbitrary portion of the material to be doped, ion irradiation is performed by scanning.

In the present invention, in principle, the length of one side of the substrate is restricted by the length of the plasma, but the length of the other side is not a limiting factor other than the size of the doping chamber. If the width of the discharge space is sufficiently narrow, it is possible to easily generate plasma in which the uniformity in the lengthwise direction is maintained at about 2 m. Of course, the width of the ion beam at that time may be on the order of centimeters.

Therefore, such a linear ion doping apparatus is suitable for processing a large area substrate or a large number of substrates at the same time. For example, a substrate having a maximum size of 2 m × xm can be relatively easily doped. x is determined by the size of the doping device.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION FIG. 3A shows the concept of an embodiment of the present invention. The ion doping apparatus of the present invention is also composed of an ion source / accelerator 13, a doping chamber 15, a power supply 14, a gas box 19, and an exhaust unit 20 as in the conventional case.
However, unlike the conventional one, the ion source / accelerator 13 generates an ion flow having a linear or rectangular cross section. Further, the substrate holder 17 is provided with a mechanism for moving during doping. The long direction of the ion flow is perpendicular to the plane of the drawing.

In the ion doping apparatus of the present invention, the shape of the substrate (material to be doped) that can be processed is not related to the shape of the cross section of the plasma space 4 in the ion source 13. However, the length of one shorter side of the substrate is required to be equal to or less than the length of the plasma space 4 in the longitudinal direction. Regarding the size of the other side of the substrate, there are no limiting factors other than the size of the doping chamber.

FIG. 3B shows a state of a cross section perpendicular to the ion flow. That is, the ion source / accelerator 13 (L ₁ ×
The shape of L ₂ ) is not restricted by the shapes of the doping chamber 15 and the material 17 to be doped. Since the cross section of the ion flow is linear or rectangular, L ₁ <L ₂ (= the length of the cross section of the ion flow in the longitudinal direction).

Only the ion flow is uniform in the longitudinal direction,
The fact that the uniformity in the short direction does not matter means that there is no problem even if there is a distribution of ionic strength and ion species in the short direction, which means that a certain light ion (for example, H ⁺ , H ₂ ⁺ etc.) is effective. To separate the ions, it was necessary to exert a magnetic effect on the ion flow, but in that case, it necessarily affected the distribution of the necessary heavy ions.

Since the conventional ion doping apparatus requires the two-dimensional uniformity, it is substantially impossible to separate the ions. However, in the present invention, it is possible to easily separate them as shown in the second embodiment.

In addition, the fact that the ion flow is uniform in the lengthwise direction and the uniformity in the lengthwise direction does not matter is advantageous for the structure of the electrode for accelerating and decelerating the ion flow. In the conventional ion doping apparatus, a net-like or porous electrode was used. However, in such an electrode, some of the ions collide with the electrode body, which causes deterioration of the electrode or deterioration of the electrode constituent material. Scattering and sputtering are problems.

On the other hand, according to the present invention, as shown in the first embodiment, since the electrode having a simple shape is provided at a position distant from the ion flow, the above problem can be solved.

In the conventional semiconductor manufacturing technique, an ion implantation technique is known. At that time, a technique of electromagnetically deflecting an ion current and scanning the fixed substrate is known. However, such a method is not suitable when simultaneously doping ions having various mass / charge ratios as in the present invention, and as in the present invention, it is better to fix the ion flow and move the substrate. preferable.

This is because, in the electromagnetic ion flow deflection technique, light ions are much more likely to be deflected than heavy ions, and therefore uniform scanning cannot be performed. Since even a slight difference in mass number causes a distribution, it is not preferable to apply it to the ion doping technique aimed at by the present invention. Such an electromagnetic deflection technique can be used only when doping only a single ion species.

The ion doping apparatus of the present invention may be added with an ion focusing apparatus and an ion mass separation apparatus which are known in the conventional ion technology.

Further, in the linear ion doping technique as in the present invention, the feature that mass separation of ions is easy may be advantageous in the subsequent annealing treatment. Generally, when ion doping is performed, the atomic lattice of the irradiated object is damaged and the crystal lattice is made amorphous due to the incidence of ions on the irradiated object. In addition, the dopant does not work as a carrier simply by implanting it in the semiconductor material. Several steps are required after doping to eliminate these disadvantages.

In the above process, the most common method is thermal annealing or optical annealing. These anneals allow the dopant to bond to the semiconductor material lattice. However, in the case of photo-annealing, the light must reach the above-mentioned lattice damage portion.

Further, the step of adding hydrogen for eliminating the level (non-bonding hand) that cannot be completely resolved by the annealing is also generally performed. This process is hereinafter referred to as hydrogenation.
Hydrogen easily penetrates into the semiconductor material at a temperature of about 350 ° C. and serves to eliminate the above levels.

In any case, providing these post-doping steps increases the number of steps and is not good in terms of cost and throughput. By performing thermal annealing and hydrogenation at the same time during doping, or by performing some of these steps during doping, the annealing / hydrogenation step can be omitted or the processing time can be shortened, or the processing temperature can be reduced. And so on.

It is relatively easy to add hydrogen and a dopant to the semiconductor material at the same time. That is, the dopant diluted with hydrogen may be ionized together with the hydrogen for doping. For example, when phosphine (PH ₃ ) diluted with hydrogen is used to implant ions with the doping apparatus shown in FIGS. 1 and 2, ions containing phosphorus (for example,
PH ₃ ⁺ , PH ₂ ^+, etc. and hydrogen ions (eg,
H ₂ ⁺ and H ⁺ ) are also injected.

However, hydrogen is too light for ions containing a dopant such as phosphorus and boron and is easily accelerated, so that hydrogen penetrates deep into the substrate. On the other hand, since the ion containing the dopant remains in a relatively shallow portion, hydrogen must be moved by thermal annealing or the like in order to repair the defect caused by the dopant.

If a linear ion beam is used,
As described above, it becomes possible for the mass separator to irradiate only desired ions on the substrate in the middle of the ion flow. If this idea is further developed, the following new doping method becomes possible. That is, it is a doping method in which ions of different masses are separated, and then each of them is accelerated at different voltages, and these beams are irradiated to the semiconductor material to implant these ions to approximately the same depth.

For example, the former and latter are made to have almost the same penetration depth by separating into ions containing hydrogen as a main component (light ions) and ions containing a dopant (heavy ions) and accelerating only the latter. As a result, the presence of the former makes it possible to perform some or all of the annealing process and hydrogenation process for the dopant at the same time.

That is, by making the incident speed of the hydrogen ion beam on the semiconductor material closer to the incident speed of the ion beam containing the dopant on the semiconductor material, the distribution of hydrogen and the distribution of the dopant in the semiconductor film become closer. At this time, the dopant is immediately activated by the incident energy of the ions (converted into thermal energy by collision) and the supply of hydrogen. This effect eliminates the need for a subsequent dopant activation step.

The incident angle of each ion beam may be changed in order to adjust the penetration depth. That is, the smaller the angle of incidence, the smaller the penetration depth. Magnetic and electrical effects may be used to change the incident angle. If the incident angle is too small, ions will not enter the substrate and will be reflected. If the incident angle is 40 ° or more, there is no problem.

For the above purpose, the mass separation device may be provided between the ion beam generator and the accelerator. For mass separation, a device that applies a magnetic field parallel to the longitudinal direction of the ion beam to the ion beam may be used. Ions containing a dopant may be first implanted into the semiconductor material, and then ions containing hydrogen as a main component may be implanted, or vice versa.

It is also effective to provide the ion doping apparatus of the present invention and a laser annealing apparatus utilizing a linear laser beam in the same chamber. That is, the present invention features the step of doping while scanning the substrate with a linear ion flow, and the laser annealing method using a linear laser beam which is another invention requires the same mechanism. , And paying attention to the fact that the steps using both devices are continuous, it is very effective to incorporate them into the same device rather than separate devices.

For example, JP-A-7-283151 discloses that
A multi-chamber vacuum processing apparatus having an ion doping chamber and a laser annealing chamber is disclosed. The conventional ion doping apparatus is based on collective irradiation of an ion flow having a planar cross section, and in some cases it is necessary to rotate the substrate. Therefore, the idea of integrating the ion doping chamber and the laser annealing chamber is There wasn't.

However, as in the present invention, when the ion doping apparatus also performs doping while moving the substrate by a transport mechanism similar to the linear laser annealing apparatus, it is necessary to separately provide an ion doping chamber and a laser annealing chamber. Rather, rather,
The integration is advantageous in terms of mass productivity. That is, the longitudinal direction of the cross section of the ion stream and the longitudinal direction of the cross section of the laser beam are arranged in parallel, and the substrate may be moved vertically between them in the direction. By doing so, the ion doping process and the laser annealing process can be continuously performed.

Combining the linear ion treatment apparatus with the linear laser annealing apparatus has an effect of reducing the number of steps by simultaneously performing two steps and an effect of reducing the possibility of substrate contamination. .

Furthermore, by using the ion doping apparatus of the present invention, it is possible to perform a doping process having the following features. That is, the first of the doping treatment methods according to the present invention is a process of generating a linear ion beam and mass separation of the ion beam, and at least 2
The method includes the steps of separating into two ion beams, accelerating the ion beams with different voltages, and irradiating the substrate with the ion beams at different angles.

Second Method of Doping Treatment According to the Present Invention
Includes a process of generating a linear ion beam, a process of mass-separating the ion beam into at least two types of ion beams, and a process of accelerating one of the ion beams with an acceleration voltage different from the other one. And irradiating at least two of the ion beams while moving the substrate in a direction substantially perpendicular to the linear direction of the linearly processed ion beam.

Third Method of Doping Treatment According to the Present Invention
Is a process of generating a linear ion beam containing hydrogen,
Mass separation of the ion beam into hydrogen-based and non-hydrogen-based ones, and ion beam substrates of hydrogen-based and non-hydrogen-based ones of the ion beams Irradiation with the ion beam while moving the substrate in a direction substantially perpendicular to the line direction of the linearly processed ion beam, and the process of applying energy, incident angle, etc., so that the penetration depth into the line is approximately equal. It is characterized by doing. Examples are shown below,
The present invention will be described in more detail.

[0048]

[Embodiment] [Embodiment 1] FIG. 4 shows the present embodiment. Figure 4
4A shows a schematic configuration of the ion source / accelerator of this embodiment, and FIG. 4B shows a schematic shape of electrodes of the ion source / accelerator of this embodiment. First, a description will be given with reference to FIG.

Plasma space 24 having a rectangular cross section
Then, high frequency power is applied from the high frequency power source 21 to the plasma generating electrodes 23 and 26 to generate plasma. The plasma is extracted by the extraction electrode 30 and the extraction power supply 28, and after the shape and distribution of the plasma are adjusted by the suppression electrode 31 and the suppression power supply 29, the plasma is accelerated to the required energy by the acceleration electrode 32 and the acceleration power supply 27.
Note that the suppression electrode 31 may not be provided if the uniformity of the plasma in the longitudinal direction is sufficient.

The shapes of the plasma generating electrodes 23 and 26, the extraction electrode 30, the suppression electrode 31, and the acceleration electrode 32 are shown in FIG.
It is shown in (B). That is, the extraction electrode 30, the suppression electrode 31, and the acceleration electrode 32 are hollow, and the ion flow flows through the central portion thereof. Therefore, the ions do not collide with the electrodes.

In this embodiment, plasma generating electrodes 23 and 2 are used.
6 has an interval of 1 to 10 cm, a length of 50 to 150 cm, a cross section of the cavity of the extraction electrode 30, the suppression electrode 31, and the acceleration electrode 32 in the short direction of 1 to 15 cm, and the long direction of 50. It is good to be ~ 170 cm.

The overall structure of the ion doping apparatus may be the same as that shown in FIG. In this embodiment, since ions are introduced without mass separation, for example, when phosphine diluted with hydrogen is used as a doping gas, heavy ions (PH ₃ ⁺ , P ₃
Both H ₂ ⁺ etc.) and light ions (eg H ⁺ , H ₂ ⁺ etc.) are introduced with the same areal density. The same thing occurs in the implantation of boron and antimony.

This has the advantage that crystallization is carried out at a low temperature during recrystallization. That is, Si—H bonds in the material undergo a condensation process in which hydrogen molecules are released,
This is to form a Si-Si bond. This point is different from the second or third embodiment in which the injection of hydrogen molecules is positively prevented.

However, in this embodiment, it should be noted that the penetration depth differs depending on the mass and radius of the ions. Generally, light hydrogen ions are concentrated in a much deeper area. An example for improving this point will be described later. (Examples 5 to 7)

[Embodiment 2] This embodiment shows an example in which a mass separator is provided in the ion source / ion accelerator of the ion doping apparatus shown in Embodiment 1. This embodiment will be described with reference to FIG. FIG. 5A shows the outline of the configuration of the ion source / accelerator of this embodiment. First, a description will be given with reference to FIG. In the plasma space 24 having a rectangular cross section, high frequency power is applied to the plasma generating electrodes 23 and 26 from the high frequency power source 21 to generate plasma.

This plasma is extracted by the extraction electrode 30 and the extraction power supply 28, and is accelerated by the acceleration power supply 27. The ion stream then passes through opposite magnetic fields 34, 35 and a slit 36 therebetween.
The magnetic field 34 causes the ions to undergo a lateral force, which is why light ions (eg, H ⁺ , H ₂ ^+, etc., dotted line in the figure).
Is a heavy ion (eg, BH ₃ ⁺ , BH ₂ ⁺ , P
H ₃ ⁺ , PH ₂ ⁺ etc., bent to the left from the thin line in the figure,
It cannot pass through the slit 36. That is, the slit 36 is provided for mass separation.

FIG. 5B shows a conceptual diagram of the distribution of ions before entering the slit. The vertical axis represents the ion density (ion strength), and the horizontal axis represents the short direction of the cross section of the ion flow. Ions reflect the distribution of plasma and have a shape close to a Gaussian distribution, but the magnetic field 34 causes light ions to move to the left. FIG. 5C shows the ion distribution after passing through the slit. The slit 36 removes the peak of the light ion on the left side of the ion flow. As a result, mass separation of the ion stream can be performed.

The distribution of ions flowing through the slit 36 in the short direction is strongly influenced by the magnetic field 34, which is different from the distribution in the plasma space. There is no problem to do so.

The ion flow passing through the slit 36 receives a rightward force by the magnetic field 35 opposite to the magnetic field 34, and the trajectory is corrected. Since the force that the ions receive in the magnetic field 34 and the force that the ions receive in the magnetic field 35 have opposite directions and equal magnitudes, the ion flow eventually becomes parallel to the previous flow.

After that, after the shape and distribution are adjusted by the suppression electrode 31 and the suppression power supply 29, the acceleration electrode 32 and the acceleration power supply 3 are arranged.
By 3, the energy required is accelerated. Note that the suppression electrode 31 may not be provided if the uniformity of the plasma in the longitudinal direction is sufficient. Further, the device for applying a magnetic field and the slit as in the present embodiment may be placed between the suppression electrode and the acceleration electrode, or between the acceleration electrode and the material to be doped.

When light hydrogen ions are removed as in this example, the hydrogen-elimination condensation reaction in recrystallization as described in Example 1 is unlikely to occur. In order to solve this problem, it is sufficient to dope only hydrogen so as to have a similar depth before or after the target impurity doping step.

[Embodiment 3] This embodiment shows an example in which an ion flow focusing device is provided in an ion source / ion accelerator of an ion doping apparatus having a simple mass spectrometer. This embodiment will be described with reference to FIG. FIG. 6 (A)
Shows an outline of the configuration of the ion source / accelerator of this embodiment.
First, a description will be given according to FIG. 6 (A) and FIG. 6 (B). Note that FIG. 6A is a view seen from the longitudinal direction of the cross section of the ion flow, and FIG. 6B is a view seen from a plane perpendicular to the longitudinal direction of the cross section of the ion flow.

Unlike the first and second embodiments, the ion source of this embodiment employs the induction excitation type plasma generation method.
For that purpose, a quartz tube is used as a part of the gas line 58, and the induction coil 43 is wound around the quartz tube. Coil 4
3 is connected to a high frequency power supply 41. Note that one end of the coil is grounded. In Examples 1 and 2, grounding was performed downstream of the ions. On the other hand, in this embodiment, grounding is performed upstream of the ion flow.

The advantage of doing so is that the gas line 58 can be used near the ground level, especially in the case of inductive excitation in a thin tube. When the gas line is provided in the middle stream of the ions as in the first and second embodiments, the potential of the gas line does not matter so much, but when the downstream of the ion is grounded in the device like this embodiment, Since the potential near the line is as high as 100 kV, and a conductive material is used for the gas pipes and trousers, it is necessary to strictly insulate even the gas box and the like.

On the contrary, by grounding the upstream side of the ions as in this embodiment, the downstream side has a high (negative) potential, but since there are few objects downstream that communicate with the outside, insulation is a big problem. It does not become.

The plasma generated by the induction coil 43 is introduced into the acceleration chamber 44. Figure 6 shows the entrance to the acceleration chamber
As shown in (B), it has a characteristic shape. Here, the pressure and density of the plasma and the doping gas are drastically reduced by introducing the gas from the thin tube into the large-capacity reaction chamber.

This is preferable when focusing the ion stream as in this embodiment. Generally, the pressure of the gas line 58 in the induction coil portion is ⅕ to 1/1 / the pressure of the acceleration chamber 44.
It may be set to 100. A pressure of 10 ⁻⁴ Torr or higher is required to generate plasma.

However, the mean free path of gas molecules and ions becomes small in a space with high pressure, which is disadvantageous in accelerating ions to high energy. Further, when the ion stream is focused as in the present embodiment, the degree of focusing is lowered due to scattering due to collision of ions.

As in this embodiment, the pressure in the acceleration chamber 44 is
The above-mentioned problem can be solved by lowering the plasma source significantly (in the vicinity of the induction coil 43). In order to make the focusing effect of the ion flow effective, it is preferable to set the pressure such that the distance from the focusing device to the object to be doped is equal to or less than the mean free path.

The plasma thus introduced into the acceleration chamber is extracted by the extraction electrode 50 (and the extraction power source 48), and the acceleration electrode 52 (and the acceleration power source 47).
Is accelerated by. A coil 51 for focusing the ion flow is provided between the extraction electrode 50 and the acceleration electrode 52.
The coil 51 has a shape different from that of an ordinary solenoid.

That is, the diameter is made smaller toward the downstream side in the direction in which the ion flow is focused. On the other hand, the diameter is not changed in the direction perpendicular to it. By doing so, the ion flow can be focused in one direction. Coil 51
Can be replaced by a hollow permanent magnet having a similar shape.

The above is the plasma confinement or plasma focusing technique called the z-pinch method in principle.
Alternatively, a self-focusing method in which the magnetic field generated by the ion flow itself is used for focusing can be used. In that case, a multi-stage accelerating electrode may be provided and the electrode diameter may be made smaller toward the downstream side. Further, in order to use the self-focusing method, when an electron flow is made to flow in the opposite direction to the ion flow, the amount of current increases and the repulsion between ions is shielded by the electrons (shield effect).
So it is more effective in focusing.

Next, the ion currents flow in opposite magnetic fields 5
4, 55 and the slit 56 between them. The magnetic field 54 causes the ions to undergo a leftward force. Therefore, light ions (dotted line in the figure) are heavy ions (thin line in the figure).
It is bent to the left and cannot pass through the slit 56. This is the same as the second embodiment, but in this embodiment, the ion flow is focused, so that a more remarkable effect can be obtained.

FIG. 6C shows a conceptual diagram of the distribution of ions that have passed through the acceleration electrode 52. The vertical axis represents the ion density (ion strength), and the horizontal axis represents the short direction of the cross section of the ion flow. Ions reflect the distribution of plasma and have a shape close to a Gaussian distribution, but light ions are more strongly focused and concentrated in the center than heavy ions.

When the ion flow having such a distribution passes through the magnetic field 54, light ions move to the left as in the second embodiment. FIG. 6D shows a conceptual diagram of the distribution of ions before entering the slit. FIG. 6E shows the distribution of ions after passing through the slit. The slit 56 removes the light ion peak on the left side of the ion flow.
As a result, mass separation of the ion stream can be performed. The characteristic of this embodiment is that light ions have a higher degree of integration, so that the effect of separation by the slits becomes remarkable.

The ion flow passing through the slit 56 receives a rightward force by the magnetic field 55, and the trajectory is corrected. Since the force that the ions receive in the magnetic field 54 and the force that the ions receive in the magnetic field 55 have opposite directions and equal magnitudes, the ion flow is eventually parallel to the previous flow. In this way, an ion flow having a linear cross section can be obtained.

[Embodiment 4] This embodiment relates to an apparatus in which the ion doping apparatus of the present invention and a laser annealing apparatus using linear laser light are provided in the same chamber. That is, the present invention features the step of doping while scanning the substrate with a linear ion flow, and the laser annealing method using a linear laser beam which is another invention requires the same mechanism. It focuses on.

For example, Japanese Patent Laid-Open No. 7-283151 discloses a multi-chamber vacuum processing apparatus having an ion doping chamber and a laser annealing chamber. The conventional ion doping apparatus is based on collective irradiation of an ion flow having a planar cross section, and in some cases it is necessary to rotate the substrate. Therefore, the idea of integrating the ion doping chamber and the laser annealing chamber There was no.

However, as in the present invention, in the case where the ion doping apparatus also performs the doping while moving the substrate by the transportation mechanism similar to the linear laser annealing apparatus, it is necessary to provide the ion doping chamber and the laser annealing chamber separately. Rather, rather,
The integration is advantageous in terms of mass productivity. That is, the longitudinal direction of the cross section of the ion stream and the longitudinal direction of the cross section of the laser beam are arranged in parallel, and the substrate may be moved vertically between them in the direction. By doing so, the ion doping process and the laser annealing process can be continuously performed.

This embodiment will be described with reference to FIG. Figure 7
(A) is a conceptual diagram of a cross section of the device of the present embodiment, and
FIG. 7B is a conceptual view of the apparatus of this embodiment as viewed from above (introduction direction of ion flow or introduction direction of laser light).

The ion doping / laser annealing apparatus of the present invention comprises an ion source / accelerator 63, a doping chamber 65, a power supply 64, a gas box 69, and an exhaust unit 70, like the ion doping apparatus of the other embodiments.
However, in addition to that, it has a laser device 61 and an optical system 62. It also has a reserve chamber 68. Of course, the doping chamber 65 is provided with a window 73 for introducing laser light. The window 73 for introducing the laser beam is provided in parallel with the window 72 for introducing the ion flow.

The substrate 66 is held by the substrate holder 67,
The substrate holder 67 moves the doping chamber 65 in at least one direction by the transfer mechanism 71. Board holder 6
The 7 may be provided with a heater or the like. The long direction of the ion flow is perpendicular to the plane of the drawing.

[Embodiment 5] In this embodiment, as for the apparatus having the ion forming means and the apparatus having the means for accelerating the ions, those having the same configurations as those of the apparatus shown in FIG. 4 are used. FIG. 8 shows a conceptual diagram of the ion doping apparatus used in this embodiment. The dopant gas is ionized by the plasma generating electrodes 82 and 83 to which high frequency power is applied from the high frequency power supply 81. The ions are extracted by the extraction electrode 84.

Further, the doping apparatus of this embodiment is provided with means 85 for applying a magnetic field to the ion beam. As a result, light ions (ions containing hydrogen as a main component) are largely deflected. On the other hand, heavy ions (ions containing dopant)
The deviation of is slight. In the apparatus of this embodiment, a suppression electrode 86 and an acceleration electrode 87 are provided in the passage of heavy ions, and the ion beam is selectively accelerated to irradiate the substrate. However, since light ions are not provided with an accelerating electrode in the passage, they are irradiated to the substrate 88 on the stage (not shown) with the energy accelerated by the extraction electrode 84.

In the present embodiment, the ion beam irradiates the substrate 88 in a curtain shape like a waterfall. The substrate 88 is formed so that the dopant is evenly spread over the entire substrate.
Doping is performed while scanning. The dose amount is controlled by the scanning speed of the substrate and the ion current value. The scanning direction at this time is substantially perpendicular to the curtain surface formed by the dopant.

The ion waterfall formed by this device has a width of 2 m.
It This device uses phosphorus or boron as a dopant
Used to add to conductor material. P for the above ions
H_y ⁺Or B2H_x ⁺In addition to ions, a large amount of H_Two ⁺Io
Are included. In this embodiment, hydrogen is used at a concentration of about 5%.
PH for diluted semiconductor_ThreeOr B_TwoH₆Using gas
It was

By forming a magnetic field in the direction perpendicular to the ion flow and including the curtain surface of the ions, a force in the direction perpendicular to the ion flow is applied to the ion flow. this is,
It is called Lorentz force. Equation of motion Ma =
From qvB, it can be easily seen that the acceleration a of the ion due to the magnetic field B is inversely proportional to the ion mass M and proportional to the charge q of the ion. The ion velocity component v after the magnetic field is incident in the direction of the ion flow before the magnetic field is incident depends on the mass M of the ions.

In the case of the present embodiment, the majority of ions to be accelerated have a charge of 1, so it can be considered that the above-mentioned acceleration depends only on the mass of the ions. Ions and H ₂ ⁺ ions contained in the gas used in this example have a molecular weight of 2, PH
_{The y} ⁺ ion has a molecular weight of about 34, and the B ₂ H _x ⁺ ion has a molecular weight of about 24 to 26. Also, the velocity component v
It can be seen that the H ₂ ⁺ ion is subjected to 10 to 100 times the acceleration in the vertical direction of the ion flow as compared with the ion containing the dopant, taking into account the mass dependence of Therefore, by applying a magnetic field to the ion stream, mass separation of the ion stream can be performed.

In order to appropriately change only the flow of H ₂ ⁺ ions without substantially changing the direction of the ion flow containing the dopant, the extraction voltage is set to about 1 to 10 kV and the magnetic field shown in FIG. It was good to apply a magnetic field of about 1 to 10 tesla, preferably about 0.5 to 2 tesla.

The place where the magnetic field is formed is immediately after the extraction electrode. This is because if the ions are bent while the kinetic energy of the ions is still small, the ions can be bent greatly with a small amount of energy. The H ₂ ⁺ ions bent immediately after the extraction electrode 84 reach the substrate 88 on the stage without passing through the suppression electrode 86 and the acceleration electrode 87. By doing so, the velocity of H ₂ ⁺ ions when entering the substrate can be suppressed.

The incident angle of H ₂ ⁺ ions when reaching the substrate was about 50 °. The angle was sufficient for ions to enter the substrate. On the other hand, the ion flow containing the dopant was irradiated on the substrate after passing through the suppression electrode and the acceleration electrode with almost no influence of the magnetic field. The incident angle was approximately 90 °.

By the above-described ion acceleration method, it became possible to suppress the velocity of H ₂ ⁺ ions as much as possible and to implant the dopant to a desired depth. In an isoelectric field, the lighter the ions and the higher the charge, the more likely they are to be accelerated. Therefore, if the ion stream is not mass-separated, the lighter the ions are, the faster the ions are implanted into the substrate. That is,
The lighter the ions, the deeper they are implanted into the substrate.

However, according to the method of this embodiment, in this embodiment, the velocity of H ₂ ⁺ ions corresponding to light ions at the time of substrate incidence and the velocity of ions containing a dopant corresponding to heavy ions at the time of substrate incidence. , And the velocity of light ions could be slower than that of heavy ions.

By controlling the speed in this way
H_Two ⁺In the substrate of ions containing ions and dopants
The depth distribution of can be made similar. This conclusion
Fruit, H_Two ⁺Heat due to release of kinetic energy of ions
Can act more directly on the dopant
It became so. The heat strikes the ions containing the dopant.
Repair of lattice defects formed by
Used for activation. Furthermore, the heat and a large amount of hydrogen
Used for the end of the unconnected hand of.

Generally speaking, the damage caused by the doping significantly deteriorates the characteristics of the semiconductor material, and therefore some kind of repair must be added. Conventionally, the damage is recovered by an annealing means such as applying heat or irradiating light. Alternatively, it was effective to add hydrogen to the damaged portion for the purpose of terminating the lattice defect portion and bond the hydrogen to the lattice defect by annealing.

By the way, as described above, when all the ions are vertically incident without mass separation, the incident velocity Vα of the heavy ions and the incident velocity Vβ of the light ions are Vα <<
Since there is a relationship of Vβ, relatively light hydrogen ions are distributed deep in the semiconductor film (FIG. 10B), whereas relatively heavy ions are distributed in a shallow portion of the film (FIG. 10).
(A)).

That is, there is a relationship of d ₁ << d ₂ between the former central depth d ₂ and the latter central depth d ₁ . Therefore, the distribution of hydrogen ions and the distribution of lattice defects due to the dopant are deviated, and the hydrogen ions are not used efficiently for repairing the defects.

However, when the mass separation of the ions is performed by the method shown in this embodiment and the incident velocities are substantially equal, the penetration depth of the hydrogen ions (FIG. 10D) and the distribution of the dopant (FIG. 10C )) Approached or matched, and as a result, the effect of repairing the above damage was significantly improved. The repair effect is a termination effect of lattice defects of the hydrogen ions and a thermal annealing effect caused by the loss of kinetic energy in the film between the hydrogen ions and the ions containing the dopant.

This effect was comparable to the conventional post-doping treatment (described in the previous paragraph). The higher the concentration of hydrogen ions in the plasma, the higher the effect. However, considering the throughput, the concentration of the hydrogen ions in the plasma was 50 to 90%.

When the substrate is scanned while being irradiated with ions, in this embodiment, H ₂ ⁺ ions are first implanted into the substrate, and then ions containing a dopant such as PH _y ⁺ or B ₂ H _x ⁺ ions are added. The direction of the substrate scan was determined so that it was driven in. Since H ₂ ⁺ ions are smaller and lighter than the main atoms constituting the semiconductor film, they are implanted into the substrate without breaking the lattice of the semiconductor material so much that the substrate temperature rises due to the kinetic energy lost by the H ₂ ⁺ ions. To do.

After that, ions containing a heavy dopant are implanted. The elevated substrate temperature and hydrogen are used to repair the lattice defects and activate the dopant. Thus, annealing and hydrogenation could be performed simultaneously with doping.

Example 6 In this example, an apparatus exactly the same as in Example 5 was used and only the scanning direction of the substrate was changed.
That is, when the substrate is scanned while being irradiated with ions, first, ions containing a dopant such as PH _y ⁺ or B ₂ H _x ⁺ ions are implanted into the substrate, and then H ₂ ⁺ ions are implanted. Was scanned.

Ions containing a heavy dopant are as heavy as the main atoms forming the semiconductor film, and thus have an effect on the lattice of the semiconductor material to the extent that the characteristics of the semiconductor are significantly reduced. After that, H ₂ ⁺ ions are implanted into the substrate,
The substrate temperature rises due to the kinetic energy lost by the H ₂ ⁺ ions. The temperature and the supply of hydrogen at this time repair the lattice defects and activate the dopant.

This example had the effects of repairing the lattice defects and activating the dopant, which were almost the same as those of the example 5. This example shows that the order of implanting hydrogen ions and ions containing a dopant into a substrate does not affect the effects of the present invention.

[Embodiment 7] FIG. 9 shows a conceptual diagram of an ion doping apparatus used in this embodiment. The difference from the doping apparatus described in Embodiments 5 and 6 is that the doping apparatus has means for applying an additional electric field to the region where the magnetic field is applied to the ion flow. The above-mentioned means are also the same as those of the devices of the first and second embodiments.
Allows mass separation of the ion stream. The difference is that, ideally, mass separation can be performed without bending the flow of ions containing the dopant at all. This mass separator is E × B
Called a separator.

The dopant gas is ionized by the plasma generating electrodes 92, 93 to which high frequency power is applied from the high frequency power supply 91. This ion is extracted by the extraction electrode 94.

Further, the ions 95 are mass-separated by the means 95 for applying a magnetic field to the ion beam and the electrode 96, and the light ions (ions containing hydrogen as the main component) are largely deflected. On the other hand, the deflection of heavy ions (ions containing dopant) is slight. In the apparatus of this embodiment, a suppression electrode 97 and an acceleration electrode 98 are provided in the passage of heavy ions, and the ion beam is selectively accelerated to irradiate the substrate. However, since light ions are not provided with an accelerating electrode in the passage, they are irradiated to the substrate 99 on the stage (not shown) as they are with the energy accelerated by the extraction electrode 94.

Also in this embodiment, the ions are applied to the substrate 99 in a curtain shape like a waterfall. Doping is performed while scanning the substrate so that the dopant is evenly distributed over the entire substrate. The dose amount is controlled by the scanning speed of the substrate and the ion current value. The scanning direction at this time is substantially perpendicular to the curtain surface formed by the dopant.

The ion waterfall formed by this device has a width of 2 m.
It This device uses phosphorus or boron as a dopant
Used to add to conductor material. P for the above ions
H_y ⁺Or B_TwoH_x ⁺In addition to ions, a large amount of H_Two ⁺Io
Are included. In this embodiment, hydrogen is used at a concentration of about 5%.
PH for diluted semiconductor_ThreeOr B_TwoH₆Using gas
It was

By forming a magnetic field in the direction perpendicular to the ion flow and including the curtain surface of the ions, a force in the direction perpendicular to the ion flow is applied to the ion flow. This is called Lorentz force. Equation of motion F = qv
From B-qE, the lateral force F that the ion flow receives can be seen. In order not to bend the ion flow, F may be set to 0.

Since the ion velocity component v in the direction of the ion flow before the magnetic field is incident after the magnetic field is incident depends on the mass M of the ion, the velocity v of the ion containing the dopant is substituted into the above equation of motion to obtain the force Magnetic field B and electric field E so that F becomes 0
Can be adjusted. At this time, the hydrogen ions have a velocity different from the velocity v of the ions containing the dopant, so that the hydrogen ions receive a force F that is not zero. Therefore, it is understood that the present apparatus can perform mass separation.

To properly change the flow of H ₂ ⁺ ions,
The extraction voltage is set to about 1 to 10 kV, and about 0.1 to 10 Tesla in the direction of the magnetic field shown in FIG.
It was good to add a magnetic field of about 5 to 2 Tesla.

The place where the magnetic field is formed is immediately after the extraction electrode 94. This is because if the ions are bent while the kinetic energy of the ions is still small, the ions can be bent greatly with a small amount of energy. The H ₂ ⁺ ions bent immediately after the extraction electrode 94 are suppressed electrode 97 and acceleration electrode 98.
Reach the substrate on the stage without passing through. By doing so, the velocity of H ₂ ⁺ ions when entering the substrate can be suppressed.

The incident angle of H ₂ ⁺ ions when reaching the substrate was about 45 °. The angle was sufficient for ions to enter the substrate. On the other hand, the ion flow containing the dopant was irradiated on the substrate after passing through the suppression electrode 97 and the acceleration electrode 98 with almost no influence of the E × B separator.

The above ion acceleration method provided the same effects as the methods shown in Examples 5 and 6. The advantage of the present embodiment over the fifth and sixth embodiments is that the extraction electrode 94, the suppression electrode 97, and the acceleration electrode 98 can be made smaller because the ions containing the dopant reach the substrate almost straight. However, since the E × B separator has a slightly complicated structure, the fifth and sixth embodiments are superior in terms of design and maintenance. The present embodiment was effective regardless of the scanning direction of the substrate as shown in the fifth and sixth embodiments.

[0116]

According to the present invention, an ion doping apparatus capable of processing a large area can be obtained. Further, it is possible to eliminate the need for the annealing step / hydrogenation step, shorten the processing time of these steps, or reduce the processing temperature. The effects provided by the present invention are as described above. As described above, the present invention is industrially useful.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of an ion source / accelerator of a conventional ion doping apparatus.

FIG. 2 is a diagram showing a schematic configuration of a conventional ion doping apparatus.

FIG. 3 is a diagram showing a schematic configuration of an ion doping apparatus of the present invention.

FIG. 4 is a diagram showing an outline of an ion source / accelerator of an ion doping apparatus of Example 1 and an outline of an electrode shape.

FIG. 5 is a diagram showing an outline of an ion source / accelerator of an ion doping apparatus according to a second embodiment and an operation principle and the like.

FIG. 6 is a diagram showing an outline of an ion source / accelerator of an ion doping apparatus according to a third embodiment, an operation principle, and the like.

FIG. 7 is a diagram showing an outline of a configuration of an ion doping apparatus of Example 4.

FIG. 8 is a diagram showing an outline of an ion source / accelerator of an ion doping apparatus of Examples 5 and 6.

FIG. 9 is a diagram showing an outline of an ion source / accelerator of an ion doping apparatus according to a seventh embodiment.

FIG. 10 is a diagram showing the relationship between the incident velocity of ions and the penetration depth.

[Explanation of symbols]

1,21 High frequency power supply 2 matching boxes 3, 23 Plasma generation electrode 4, 24 Plasma space 5 insulator 6,26 Plasma generation electrode 7, 27, 33 Acceleration power supply 8, 28 drawer power supply 9, 29 Control power supply 10, 30 Extraction electrode 11, 31 Suppression electrode 12, 32 Accelerator electrode 13 Ion source / accelerator 14 power supply 15 Doping room 16 Doped material 17 Board holder 18 gas lines 19 gas box 20 exhaust system 34, 35 magnetic field 36 slits

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 21/22 H01L 21/265 F (72) Inventor Koichiro Tanaka 398 Hase, Atsugi, Kanagawa Prefecture Semiconductor Energy Research Laboratory F-term (reference) 4K029 BD01 DA08 DE03 DE04 GA01 KA01 5C034 BB06 CC01

Claims (8)

[Claims] 1. An apparatus for generating an ion flow having a linear or rectangular cross section, a means for generating a linear laser beam, and a transfer mechanism for moving a substrate in a direction perpendicular to the longitudinal direction of the cross section of the ion flow. And a doping chamber having the doping chamber, wherein in the doping chamber, the substrate is irradiated with the ion stream and the linear laser light. 2. An apparatus for generating an ion current having a linear or rectangular cross section, a means for generating a linear laser light, a window for introducing the ion current, a window for introducing the linear laser light, and And a doping chamber having a transport mechanism for moving the substrate in a direction perpendicular to the longitudinal direction of the cross section of the ion flow, in the doping chamber, the irradiation of the ion flow and the irradiation of the linear laser light with respect to the substrate A doping processing apparatus characterized by being performed as follows. 3. An ion flow cross section having a linear or rectangular cross section, a means for generating a linear laser beam, and a doping chamber having a transfer mechanism for moving a substrate, the cross section of the ion flow. And the longitudinal direction of the cross section of the linear laser light are parallel, by the transport mechanism, the longitudinal direction of the cross section of the ion flow and the direction perpendicular to the longitudinal direction of the cross section of the linear laser light. The substrate is moved to a substrate, and the ion flow irradiation and the linear laser light irradiation are performed on the substrate in the doping chamber. 4. An apparatus for generating an ion current having a linear or rectangular cross section, a means for generating a linear laser beam, a linear or rectangular window for introducing the ion current, and a window for introducing the ion current. A linear or rectangular window that is provided in parallel with and that introduces the linear laser light, moves the substrate in the longitudinal direction of the cross section of the ion current and in the direction perpendicular to the longitudinal direction of the cross section of the linear laser light. A doping chamber having a transport mechanism, wherein the ion flow irradiation and the linear laser light irradiation are performed on the substrate in the doping chamber. 5. The doping processing apparatus according to claim 1, wherein the transfer mechanism includes a substrate holder having a heater. 6. The apparatus for generating an ion flow according to claim 1, wherein the device for generating an ion flow is for generating a plasma space and for extracting an ion flow from the plasma generated in the plasma space. A doping treatment apparatus comprising: an extraction electrode; and an acceleration electrode having a linear or rectangular cavity for accelerating the ion flow. 7. The device for generating an ion flow according to claim 1, further comprising: a plasma space for generating plasma, and an extraction electrode for extracting the ion flow from the plasma generated in the plasma space. A doping treatment apparatus comprising: a means for mass-separating the ion flow; and an acceleration electrode having a linear or rectangular cavity for accelerating the ion flow separated by the mass-separation means. 8. The plasma space, the extraction electrode, and the acceleration electrode according to claim 6 or 7,
The doping processing apparatus, wherein the ion flow is arranged so as to reach the substrate straight from the plasma space.