JPS63187545A - Ion implanting apparatus - Google Patents

Abstract

PURPOSE:To allow the ion implantation excellent in uniformity and reproduci bility by changing the scanning amplitude in response to the ion implantation angle. CONSTITUTION:The strength of the scanning electric field applied to the Y- direction and X-direction scanning electrode plates 3, 4 from a scanning power supply controller 8, i.e., scanning amplitude, is controlled to be changed in response to the angle between an ion beam 6 and a sample substrate 7. That is, in an ion beam scan type ion implanting apparatus, the scanning amplitude of the ion beam at least in one of the X direction and Y direction is controlled to be continuously increased or decreased in order to prevent or decrease the occurrence of the 'incidence effect' by ion beam scanning, thereby the scanning speed and the number of scans of the ion beam 6 on the surface of the sample substrate 7 are continuously changed, thus the ion implantation quantity to the surface of the said sample substrate 7 is controlled, and uniform ion implan tation can be realized reproducibly.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ion implantation device, and more specifically,
For example, in the ion beam scanning type ion implantation equipment used in the manufacturing process of semiconductor devices, etc., it relates to an ion implantation equipment that has been improved so that ions can be implanted uniformly and accurately regardless of changes in the ion implantation angle. be.

[Conventional technology]

Conventionally, brainer technology has been applied to form isolation regions between elements during the manufacture of semiconductor devices, but as semiconductor devices become more highly integrated, such brainer technology alone is insufficient to form isolation regions between elements. There is a limit to miniaturization of isolation regions, and it is becoming difficult to incorporate more element configurations within an allowable chip size.

Therefore, recently, in order to achieve even higher integration in semiconductor devices, devices such as isolation layers or [
The use of a so-called dug trench structure is being considered to form capacitance in lRAM (dynamic random access memory), and in order to adopt such a dug trench structure, it is necessary to improve semiconductor devices. In the manufacturing process, it is necessary to introduce impurities such as poron or arsenic into the sidewalls of the trenches with good control.

However, in conventional semiconductor device manufacturing methods, solid-phase diffusion or gas-based vapor-phase diffusion is usually used to introduce impurities into such trench structures. In these methods, the controllability of the impurity concentration in the formed impurity layer, the diffusion method, etc., especially when forming a shallow impurity layer, and the reproducibility are poor.
This has the disadvantage that it becomes a major obstacle in miniaturizing semiconductor devices, and for this reason, when introducing impurities into such a trench structure, it is necessary to use ion implantation methods with excellent controllability and reproducibility of the amount of impurity ion implantation. An injection method is used.

FIG. 1 shows a general configuration of a general ion implantation apparatus.

That is, in the configuration shown in FIG. 1, reference numeral 1 is an ion source that ionizes and extracts a substance containing desired impurities, 2 is an analysis electromagnet that selects only the necessary impurity ions, and 3 and 4 are in the horizontal direction (hereinafter referred to as "horizontal direction").

(hereinafter referred to as the Y direction) and 6 orthogonal directions (hereinafter referred to as the X direction)
5 is a sample stage, 6 is a controlled ion beam, 7 is a semiconductor substrate as a sample, 8 is a Y direction and an X direction
This is a scanning power supply controller that controls the scanning vibration I11 of the ion beam 6 by controlling the electric field strength applied to the scanning electrode plate 3.4 in the direction.

Therefore, in the case of this ion implanter, the ion beam 6 is applied via the scanning electrode plates 3.4 in the Y and X directions.
The surface of the sample plate 7 held on the sample stage 5 is scanned and irradiated in the Y direction and the X direction, allowing desired impurity ions to be implanted into the surface of the substrate.

[Problem that the invention seeks to solve]

However, when impurity ions are implanted into the side wall of the trench using such a general ion implantation device, since the target part is the side wall of the trench, the ion implantation is difficult. It is necessary to increase the angle.

FIG. 4 shows, for example, when ions are implanted into the side wall of such a trench. FIG. 2 is an explanatory diagram showing a schematic arrangement of an ion beam 6 and a sample substrate 7. FIG.

That is, in the configuration shown in FIG. 4, the sample substrate 7 is held on the support stand 5 supported by the fulcrum 9 so as to form a predetermined angle with respect to the ion beam 6. In this case, the angle of implantation of the ion beam 8 into the sample substrate 7 is zero.

In addition, in an ion implantation apparatus that applies conventional means, when scanning the ion beam in the X direction and the Y direction,
As shown in FIG. 5, each scanning frequency is fixed, and the scanning amplitude is also fixed to be larger than the sample substrate.

That is, FIG. 5 is an explanatory diagram showing the scanning frequency and scanning amplitude when scanning the ion beam 6 in the X direction and the Y direction. Here, the same figure (a) shows the scanning frequency and scanning amplitude in the X direction, the same figure (b) shows the scanning frequency and the scanning amplitude in the Y direction, and the same figure (C ), the ion beam 6 is scanned in the X direction and the Y direction by applying sawtooth electric fields shown in the figures (a) and (b) to the scanning electrode plates 3 and 4, respectively. The circular shape indicated by the broken line is the size of the sample substrate 7.

Conventionally, when performing ion implantation using an ion implantation device, as the angle of implantation of ions into the sample substrate 7 increases, the implantation is performed in the X direction and at the same scanning wave number and scanning amplitude, respectively. When scanning in the Y direction, a problem arises in that the uniformity of the amount of ions implanted onto the sample substrate 7 deteriorates due to the influence of the so-called "incidence effect", and the amount of ions implanted itself also decreases.

Here, the above-mentioned "incidence effect" means that as the ion implantation angle increases, the distance that the ion beam 6 reaches the sample J substrate 7 becomes longer or shorter, and as this distance increases, the ion beam 6 spreads. At the same time, the distribution density of ions in that region decreases, resulting in deterioration of the uniformity of ion implantation.
In addition, it causes a decrease in the amount of injected clay, which in such cases is an undesirable effect.

Further, FIG. 6 is an explanatory diagram showing the sheet resistance distribution of sample 1.1-plate 7 when ions are implanted onto the surface of sample substrate 7 with the implantation angle set at 45 degrees.

That is, in FIG. 6, the scanning frequency in the X direction is 1000 Hz and the scanning frequency in the Y direction is 100 Hz, which are fixed respectively, and the scanning amplitude is the same as when the ion implantation angle is 0 degrees. The amplitudes in the X and Y directions are set to sufficiently cover the sample substrate 7, and these are also fixed.

In the case of this FIG. 6, the contour lines displayed on the sample substrate 7 are drawn at intervals of 0.5z of the reference value, with the central part represented by the thick line as the reference value, and the contour lines are drawn at intervals of 0.5z of the reference value. The symbol O indicates an area where the sheet resistance is higher than the reference value, and the symbol O indicates an area where the sheet resistance is lower than the reference value. One half is located far from the fulcrum 8 and is ion-implanted.

As is clear from FIG. 6, the sheet resistance increases from the lower side to the upper side of the sample substrate 7.
[1] and the number of ion-implanted stars is decreasing, and this uneven distribution of ion-implanted rμ is due to the ion beam 6
is scanned in the X and Y directions, and its scanning frequency and scanning vibration are fixed at 1.

Furthermore, FIG. 7 is an explanatory diagram showing that the number of implantation needles themselves decreases when the ion implantation angle increases, and for ease of understanding, the ion beam 6 is The sample substrate 7 is also assumed to have a rectangular surface shape. As you can see, FIG. 5A shows the case where the ion implantation angle is 0 degrees, and FIG. 2B shows the case where the ion implantation angle is θ other than 0 degrees.

In these FIGS. 7(a) and (b), if the scanning amplitude of the ion beam 6 in the X direction is W and the scanning amplitude in the Y direction is W, and it is assumed that these are the same and fixed, then the same The scanning area of the ion beam 6 is also the same.

In FIG. 7(a), since the ion implantation angle is O1'f, the angle between the ion beam 6 and the sample substrate 7 is 0 direct, and the incident area of the ion beam 6 on the sample substrate 7 is also This is the size of the surface shape. However,
On the other hand, in the same figure (b3), the ion implantation angle is θ
Therefore, the area of incidence of the ion beam e on the sample substrate 7 does not change in the Y direction, but cos in the X direction.
It will decrease substantially with θ.

Therefore, in conventional ion implanters, even if the ion implantation angle is changed, the scanning amplitudes of the ion beam 6 in the X and Y directions remain fixed and remain the same regardless of the implantation angle. In addition, regarding beam radio waves, the current irradiated only to the sample substrate 7 is not measured, but the entire scanning area of the ion beam is measured, so the incident area of the ion beam 6 can be reduced by increasing the implantation angle. The decrease in the beam current to the sample substrate 7, in other words, a decrease in ion implantation errors.

As explained above, when ions are implanted into the side wall of a trench structure by conventional means using an ion implantation device, the sample substrate 7 is inevitably tilted, or in other words, the sample substrate 7 is tilted. The ion implantation angle must be set to a zero angle other than 0 degrees, and therefore, ions can be implanted into the side walls of the trench structure using one sample substrate. The problem is that the semiconductor devices become uneven and the number of injectors also decreases, resulting in variations in the characteristics of the resulting semiconductor devices, making it impossible to realize highly reliable semiconductor devices, and reducing the manufacturing yield. there were.

This invention was made in order to solve these conventional problems, and its purpose is to improve the ion implantation over the entire surface of the sample 1 (sample) 1 (plate) even if the ion implantation angle changes. , it is possible to uniformly implant impurity ions, and the implantation field does not change, making it possible to perform ion implantation with excellent uniformity and reproducibility. To provide this type of ion implantation device. That's true.

[Means for solving problems]

In order to achieve the above object, the ion implantation apparatus according to the present invention controls the electric field strength applied to each scanning electrode plate in the X direction and the Y direction, scans the ion beam in the X direction and the Y direction, and implants the sample into the sample. When impurity ions are implanted onto the substrate, the scanning amplitude in at least one of the X direction and the Y direction is changed in accordance with the ion implantation angle between the ion beam and the sample substrate.

[For production]

That is, in the present invention, when impurity ions are implanted onto a sample substrate, at least one of the X direction and Y direction of the ion beam is applied, depending on the ion implantation angle between the ion beam and the sample substrate. By changing one scanning amplitude, it is possible to effectively compensate for changes in ion distribution and ion implantation amount due to the length of the ion beam reaching the surface of the sample substrate. Therefore, ion implantation can be performed with good uniformity and reproducibility.

〔Example〕

Hereinafter, one embodiment of the ion implantation apparatus according to the present invention will be described in detail with reference to FIGS. 1 to 3.

An example of an ion implantation apparatus to which an embodiment of the present invention is applied is the ion implantation apparatus shown in FIG. 1 described above. In the device configuration shown in FIG. 1, regarding the frequency and electric field strength of the scanning electric field applied from the scanning power supply controller 8 to each scanning electrode plate 3.4, that is, the scanning frequency and scanning amplitude, in the conventional case, , these were fixed, but in this embodiment, the intensity of the scanning electric field applied to the Y-direction and It is controlled so that it can be changed in accordance with the angle formed by the angle.

FIG. 2 shows the X direction and Y direction according to one embodiment of the present invention.
It shows a change in the scanning amplitude of the ion beam 8 in the direction,
Figure (a) shows the scanning waveform in the X direction.

FIG. 5B shows scanning waveforms in the Y direction.

That is, as is clear from these FIGS. 2(a) and 2(b), in the case of this FIG. 2 embodiment, the scanning frequency and scanning amplitude of the ion beam 6 in the Y direction are the same as in the conventional case. However, the scanning amplitude of the ion beam 6 in the X direction increases as the scanning waveform in the Y direction increases, that is, from the lower side to the upper side of the sample substrate 7 shown in FIG. The scanning amplitude is controlled to decrease toward the side.

In each of the scanning waveforms shown in these FF12 figures (a) and (b), the area where the scanning amplitude in the X direction is narrowed is as follows:
Corresponding to a decrease in the scanning distance of the ion beam 6 on the surface of the sample substrate 7, a decrease in the scanning distance in parentheses corresponds to a decrease in the scanning distance of the ion beam 6 on the surface of the sample substrate 7 per unit time. , which corresponds to an increase of 41° in ion implantation.

That is, this means that, for example, when the ion implantation angle increases under the conditions shown in FIG. 6, the decrease in ion implantation h) on the upper surface of the sample substrate 7 can be effectively compensated. This means that, as a result, uniform ion implantation can be performed over the entire surface of the sample substrate 7 with good reproducibility.

Also, if necessary, it is of course possible to set the control so that the scanning vibration Ill in the X direction increases as the scanning waveform in the Y direction decreases, but this second In the case of the illustrated embodiment, one important point is that the scanning amplitude in the X direction is controlled to be changed in accordance with the ion implantation angle of the ion beam 6 with respect to the sample substrate 7.

Next, FIG. 3 similarly shows changes in the scanning amplitude 111 of the ion beam 6 in the X direction and Y direction according to another embodiment of the present invention; (b) shows the scanning waveform in the Y direction.

That is, as is clear from these FIGS. 3(a) and 3(b), in the case of this FIG. 3 embodiment, the scanning amplitude of the ion beam 8 in the X direction is simply changed as in the previous example. In addition, regarding the scanning amplitude of the ion beam 6 in the Y direction,
It is controlled to vary in accordance with the ion implantation angle of the ion beam 6 with respect to the sample substrate 7.

That is, in the embodiment shown in FIG. 3 as well, when the ion implantation angle becomes large under the conditions shown in FIG. By compensating for the decrease, it is possible to improve the uniformity of ion implantation Q onto the same surface, and at the same time, it is possible to prevent a decrease in the ion implantation field itself. In other words, even in this case, when the implantation angle becomes large, the decrease in the ion implantation rate due to the decrease in the effective area of incidence of the ion beam 6 on the sample substrate 7 can be reduced in the X direction corresponding to the ion implantation angle. and Y
This is prevented by controlling the scanning amplitude of the ion beam 6 in the direction, and as a result, uniform ion implantation can be performed over the entire surface of the plate 7 with good reproducibility.

In this way, in the ion beam scanning type ion implantation apparatus, the ion beam 6 and the sample substrate 7 are aligned in at least one of the scanning amplitudes of the ion beam 6 in the X direction and the Y direction.
By controlling the scanning amplitude to vary as a function of the implantation angle of the ion beam 6, the "incidence effect", which is particularly noticeable when the implantation angle of the ion beam 6 is increased, can be improved. It is possible to prevent non-uniformity and deterioration of ion implantation caused by ion implantation.

In other words, in an ion beam scanning type ion implanter, in order to prevent or reduce the occurrence of "incidence effect" due to ion beam scanning, the scanning vibration of the ion beam 6 in the X direction and the Y direction is By continuously increasing or decreasing at least one of the widths of the sample substrate 7
By continuously changing the scanning speed and number of scans of the ion beam 6 on the surface of the sample substrate 7, it is possible to control the ion implantation onto the surface of the sample substrate 7 and achieve uniform ion implantation with good reproducibility. It is.

This also means that when impurities are introduced by ion implantation into the sidewalls of the trench structure during semiconductor device manufacturing, it is important to improve the uniformity, reproducibility, and controllability of ion implantation *1. So, 1! It can be said that it is very effective.

〔Effect of the invention〕

As described in detail below, according to the present invention, the electric field strength applied to each scanning electrode plate in the X direction and the Y direction is controlled, the ion beam is scanned in the X direction and the Y direction, and the ion beam is scanned onto the sample substrate. In an ion beam scanning type ion implantation device that implants impurity ions, the ion beam scanning amplitude in at least one of the X direction and the Y direction is
Since the ion implantation angle between the ion beam and the sample substrate is controlled and the change is controlled as a function of the same implantation angle, uniform ion implantation can be achieved over the entire surface of the sample substrate. It is possible to perform ion implantation with good uniformity, reproducibility, and controllability into the sidewalls of the trench structure on the sample substrate, and it has excellent features such as being relatively easy to implement. It is something.

[Brief explanation of the drawing]

FIG. 1 is a block diagram schematically showing the essential structure of an ion implanter to which the present invention is applied, and FIG. 2 is a diagram showing changes in the scanning amplitude of an ion beam according to an embodiment of the present invention. , FIG. 3(a) is an explanatory diagram showing the scanning waveform in the overlapping direction (X direction), FIG. 3(b) is an explanatory diagram showing the scanning waveform in the water Y direction (Y direction), and FIG. FIG. 2 is a diagram showing changes in the scanning amplitude of an ion beam according to another embodiment, in which (a) shows the scanning waveform in the direction of power arrival (X direction), and (b) shows the scanning waveform in the horizontal direction (Y direction). FIG. 3 is an explanatory diagram showing scanning waveforms in the respective directions. Furthermore, Fig. 4 is an explanatory diagram schematically showing the arrangement of the sample substrate and the ion beam when the sample substrate is irradiated with the ion beam at the ion implantation angle O, and Fig. 5 is the scanning waveform in conventional ion implantation. , where (a) is an explanatory diagram showing the scanning waveform in the vertical direction (X direction), and (b) is an explanatory diagram showing the scanning waveform in the horizontal direction (Y direction), respectively. (c) is an explanatory diagram showing the state when the electric field of each of these sawtooth waves is applied to each scanning electrode plate and the ion beam is scanned in the vertical direction (X direction) and horizontal direction (Y direction). It is. Furthermore, FIG. 6 similarly shows the conventional ion implantation angle of 45
FIG. 7 is an explanatory diagram showing the sheet resistance distribution of a sample substrate when ions are implanted at a conventional ion implantation angle. FIG. 4 is a diagram schematically showing a decrease in the amount of ions implanted into a sample substrate, and FIG.
FIG. 3B is an explanatory diagram showing the case where the ion implantation angle is θ other than 0 degrees. 1...Ion source, 2...Analysis electromagnet, 3...
・Horizontal direction (Y direction) scanning electrode plate, 4... Vertical direction (X direction) scanning electrode plate, 5... Sample stage, 6...
...Ion beam? ...Sample substrate (semiconductor substrate)
, 8...Scanning power supply controller. Agent Masuo Oiwa Figure 1 1: Ion 4 2: Iki Kameroku Stone 3: Tree - Y direction (Y direction) θ Running destination Takaki 94 ≧ Hi straight direction (
X direction) Overcoming reward λL flame 5: Ceremony cut) 6: I4 engine, 7: Input PJr Ri9 handling - (1,400 it group (Kyu) 8: Maru 2 IT Yuno E-ぢ;1) hi];(S Ilq!, Figure 2 □ - Previous Figure 3 Figure 4 Figure 5 So Figure 5 (Q) (b) Figure 5 (C) Figure 6 Figure 7 Procedural correction power ( Spontaneous) 6: i H' (7,. Showa 1939, Mon., 1933, Chief of the Bureau of Permissions Palace 1, Indication of the incident, Patent Application No. 62-19012 2,
Name of the invention Ion implantation device 3, Relationship with the case of the person making the amendment Patent applicant representative Moriya Shiki 4, agent 5, subject of amendment (1) Detailed explanation column of the invention in the specification (2) Specification Column 6 for a brief explanation of the drawings in the book, contents of the amendment (11 "Y direction" on page 4 line 3 of the specification is amended to "X direction". (2) "X direction" on the same page of the same book is changed to "X direction". (3) Correct “0 symbol is” on page 7, line 17 of the same book to “mon sign is”. (4) Correct “0 symbol is” on page 7, line 18 of the same book to “θ symbol is”. (5) Correct “W” in line 2 of page 9 of the same book to r WX J. (6) Correct “W” in line 3 of page 9 of the same book to r WY J. (7) Correct the letter “W” in line 3 of page 9 of the same book to r WY J. Correct “Y” on line 12 of page 12 to “X”. (8) Correct “X direction” on line 13 of page 18 of the same book to “Y direction”. (9) Correct line 6, 11, and 18 on page 18 of the same book. "Vertical direction"
"Horizontal direction". αC same book, same page 7. Correct "horizontal direction" in line i2, 19 to "vertical direction". aυ "Vertical direction" in line 2 on page 19 of the same book is corrected to "horizontal direction".
and correct it. that's all

Claims (2)

[Claims] (1) An ion implantation device that implants impurity ions onto a sample substrate by controlling the electric field strength applied to each scanning electrode plate in the vertical and horizontal directions and scanning the ion beam in the vertical and horizontal directions. , an ion implantation apparatus characterized in that the scanning amplitude of the ion beam in at least one of the vertical direction and the horizontal direction is changed in accordance with the ion implantation angle formed between the ion beam and the sample substrate. . (2) As the ion implantation angle between the ion beam and the sample substrate increases, the scanning amplitude of the ion beam in at least one of the vertical and horizontal directions is controlled to be smaller. An ion implantation apparatus according to claim 1.