JPS62276738A - Ion beam apparatus - Google Patents

Abstract

PURPOSE:To obtain a compact ion beam apparatus with little change of irradiation angle by forming the first and the second electrode pairs, the first magnetic pole pair and the second magnetic pole pair which deflects a deflected ion beam to the same direction as that of the beam before it is deflected. CONSTITUTION:Electrostatic deflection and magnetic deflection are made to correspond to one direction out of two directions making a right angle with each other and the deflecting directions are made to be compensated mutually by shifting their positions in the direction of ions in the electrostatic deflection and magnetic deflection respectively by forming a deflecting part, which makes a two-dimensional scanning, with the first electrode pair 71 to deflect an ion beam to x-direction, the second electrodes pair 72 to make an x-direction speed component zero by deflecting the ion beam deflected to x-direction between the two electrodes 71 to a reverse direction, the first magnetic pole pair 81 to deflect the ion beam to y-direction and the second magnetic pole pair 82 to make a y-direction speed speed component zero by deflecting the ion beam deflected to y-direction between the two magnetic poles 81 to a reverse direction. Track directions of ions emitted by the deflecting part can be thus made to keep a constant angle with the whole surface of the substrate to be treated.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention ~ [Technical Field to Which the Invention Pertains] The present invention is used as an ion implantation device in a semiconductor processing process, and is used as an ion implantation device in a semiconductor processing process. a plasma generation section that turns plasma into plasma, an ion extraction section that extracts ions with a specific polarity from the plasma in the plasma generation section, and an ion extraction section that extracts ions with a specific charge/mass ratio from among the ions extracted by the ion extraction section. An ion beam consisting of predetermined ions is obtained using a mass spectrometer that extracts only ions and an acceleration section that gives a predetermined kinetic energy to the ions extracted by the mass spectrometer. Ions are irradiated through a deflection unit that scans two-dimensionally in two directions perpendicular to the direction of travel and at right angles to each other, and guided into an implantation chamber that holds a substrate to be implanted, and the ions are irradiated onto the surface of the substrate. Regarding ion beam equipment for irradiation and implantation.

[Prior art and its problems]

FIG. 4 shows an example of the configuration of a conventional ion implanter.

In the diagram, a plasma generation unit 1 is one that generates predetermined ions by accelerating electrons emitted from a hot cathode using an electromagnetic field and colliding with introduced gas molecules or metal vapor to turn them into plasma. It is. The extraction electrode system 2 constituting the ion extraction section is disposed opposite to a slit provided in the plasma chamber constituting the plasma generation section 1, and a high voltage is applied between it and the plasma chamber to remove the plasma from the plasma. Extracts ions with specific polarity. The trajectory of the ion beam thus obtained is bent by the mass spectrometer magnet 3 constituting the mass spectrometer as shown by the broken line and the dashed-dotted line in the figure. At this time, since the radius of curvature differs depending on the charge/mass ratio of the ions, the ions passing through the slit 4 are limited to those having a specific charge/mass ratio. The acceleration tube 5 constituting the acceleration section 104 accelerates specific ions obtained by the method described above to a predetermined kinetic energy. If the kinetic energy of the ions obtained between the plasma generating section 1 and the extraction electrode system 2 is of sufficient magnitude, the accelerating tube 5 may be omitted. The lens system 6 focuses the obtained ion beam onto the surface of the substrate 10 held in the implantation chamber 11 to a predetermined irradiation area. The vertical direction parallel to the plane of the paper is the X direction; the direction perpendicular to the plane of the paper is the Y direction';
High voltages of different frequencies are applied to the deflection electrode pairs 8, and the aforementioned ion beam is uniformly irradiated onto the entire surface of the substrate 10 while being deflected by the electrode pairs 7.8. A high DC voltage is applied to the reflector electrode pair 9, and the beam trajectory is bent to remove oily atoms present in the beam just before irradiating the substrate 10.

In such a device, as shown in FIG.
The irradiation angle θ with respect to 0 changes between θO±θS, assuming that the deflection angle is θS and the irradiation angle at the center is 00. This results in the following drawbacks.

(1) Variation in implantation depth occurs as the irradiation angle changes.

(2) Since the irradiation area changes as the irradiation angle changes, variations in implantation density occur.

(3) The beam movement speed on the substrate changes with respect to a constant scan voltage, resulting in variations in implantation density.

(41 Mask 10 patterned on the surface of the substrate 10
Since 1 has a thickness, the amount and location of implanted ions within the same implantation width vary depending on the position on the substrate, as shown in 103.

Although such a drawback can be solved by reducing θS, it is not practical because it increases the size of the device, and there is a limit to reducing the variation in characteristics.

[Purpose of the invention]

An object of the present invention is to solve the above-mentioned conventional problems and provide a small ion beam device that does not change the irradiation angle.

[Key points of the invention]

In the present invention, a deflection unit that scans the ion beam two-dimensionally in two directions perpendicular to the traveling direction and at right angles to each other is provided.
a first pair of electrodes that deflect the ion beam in the same direction as the direction of travel before deflection, and a second pair of electrodes that deflect the ion beam in the same direction as the direction of travel before deflection; a first pair of magnetic poles that deflects the ion beam in the same direction as the direction in which the ion beam is traveling before deflection;
The ion beam is always incident on the substrate at a constant irradiation angle regardless of the scan width, and the first and second electrode pairs are configured with the first and second electrode pairs, respectively. By placing it inside the second magnetic pole pair,
This aims to achieve the above objectives. Hereinafter, the principle of the present invention will be explained in detail with reference to examples.

[Embodiments of the invention]

FIG. 1 and FIG. 2 show an embodiment of the present invention, and FIG. 1 shows the configuration of the deflection section with respect to the direction of beam entry,
FIG. 2 shows a front sectional view of the deflection section taken along the line A--A in FIG. 1 in the direction of the arrow. In Figure 1, 7
1 is a first electrode pair for accelerating the beam in the vertical direction (X direction) parallel to the plane of the paper; 72 is for accelerating the beam accelerated in the X direction in the opposite direction to return the X direction velocity component to zero; A second electrode pair 81 is a first magnetic pole pair for accelerating the beam in the direction perpendicular to the plane of the paper (X direction), and 82 accelerates the beam accelerated in the X direction in the opposite direction to generate an X direction velocity component. This is the second magnetic pole pair for returning to zero. Said first electrode pair 7
Alternating voltages are applied to the first and second electrode pairs 72 from a power source (not shown) with a phase difference of 180 degrees. Also,
The first pair of magnetic poles 81 and the second pair of poles 82 are driven by an alternating current from a power source (not shown) so as to generate mutually opposite magnetic fields at an excitation coil 84.

FIG. 3 is an explanatory diagram of an ion beam trajectory controlled by the deflection section shown in FIGS. 1 and 2. FIG. In the figure Ia,
The Ib plane is a virtual deflection plate that shows the respective effects of the first electrode pair 71 and the TSL magnetic pole pair 81 in FIG. Second
This is a virtual deflection plate for the magnetic pole pair 82 of FIG. Deflection plate I
When the electric field 8R between a and Ib goes from the Ia plane to the Ib plane, and the magnetic field B1 goes from the Ib plane to the Ia plane, the electric field E2 between the deflection plates I[a and nb becomes I[b plane to the TIa plane, and the magnetic field B2 is directed from the TIa plane to the IIb plane. In a normal ion beam device, since the speed of the ions in the traveling direction (z-axis direction) is high, the deflection plate I
The time it takes for an ion to pass through a, Ib, IIa, and IIb is extremely short, and for one ion l,
El within this time, B1. E2. Changes in B2 can be ignored. In a magnetic field, the ion's velocity only changes in the X direction, but the magnitude of its own velocity in the two axes does not change. Therefore, positive ions incident at a velocity ν0 along the two axes are Ia−
In Ib space, the trajectory is changed in the y-work direction by the magnetic field Bl, and in Ha IIb space, the trajectory is changed in the negative y-axis direction by the magnetic field B2, so B gives this trajectory change.
If the dimensions of the magnetic pole pair 81 and 82 and the magnetic field are set so that the relationship Ll x Bl = L2 x B2 is established between B2, the direction of emission from the deflection section will be 2 as shown by the double dashed line. parallel to the axis. Further, in the electric field, ions are accelerated in the X direction according to their residence time. Therefore I, -
In Ib space, the electric field E1 causes displacement in the X-axis direction, and IIa
In the IIb space, the electric field E2 causes displacement in the negative direction of the X-axis.

If we take into account the change in the velocity component in the X direction due to B, ,B in the residence time and take the relationship of electromagnetic field strength such that El/B, = E, zB, we get one point @ line C. , the injection direction is parallel to the two axes. Therefore, by combining the electric field deflection and magnetic field deflection as described above, it has become possible to set the trajectory of the ions so that they are always irradiated onto the substrate surface at a constant angle, as shown by the i-line 13.

〔Effect of the invention〕

As described above, the deflection unit for two-dimensionally scanning the ion beam in the x and X directions perpendicular to its traveling direction includes the first electrode pair that deflects the ion beam in the X direction;
A second electrode pair for deflecting the ion beam deflected in the X direction between the first electrode pair in the opposite direction to make the velocity component in the X direction zero, and a second electrode pair for deflecting the ion beam in the X direction. 1
and a second magnetic pole pair for deflecting the ion beam deflected in the X direction between the first magnetic pole pair in the opposite direction and zeroing out the velocity component in the X direction. The deflection and the magnetic field deflection correspond to each of the two orthogonal directions,
In addition, since the electric field deflection and magnetic field deflection are shifted in position in the ion traveling direction to correct each other, the trajectory direction of the ions ejected from the deflection section is always kept constant over the entire surface to be processed of the substrate. (1) There is no variation in implant depth depending on the irradiation position on the substrate surface.

(2) There is no change in the irradiation area depending on the irradiation position on the substrate surface, and there is no variation in implantation density.

(3) Since the irradiation angle does not change, there is no change in irradiation time depending on the irradiation position, and there is no variation in implantation density.

(4) Since there is no change in the irradiation angle, ion implantation into fine patterns is possible without being affected by the thickness of the mask on the substrate surface.

Effects such as this can be obtained. In addition, the first electrode pair is arranged inside the first magnetic pole pair, and the second electrode pair is arranged inside the second magnetic pole pair, and the electric field deflection and the magnetic field deflection are controlled by IK in the same space. By doing so, the above-mentioned effects can be obtained with a small deflection section and therefore with a small ion beam device.

It goes without saying that even when the scan width is small and the deflection correction, that is, the 2' electrode pair and the second magnetic pole pair are unnecessary, there is an advantage of miniaturization by combined use of the electric S field.

[Brief explanation of the drawing]

FIGS. 1 and 2 illustrate an embodiment of a deflection section of an ion beam apparatus constructed according to the present invention. FIG. 3 is an explanatory diagram showing the principle of ion beam trajectory control according to the present invention;
FIG. 4 is an explanatory diagram showing an example of the configuration of a conventional ion beam apparatus, and FIG. 5 is an explanatory diagram showing differences in implantation conditions based on differences in irradiation angle with respect to the substrate surface. DESCRIPTION OF SYMBOLS 1... Plasma generation part, 2... Extraction electrode system (ion extraction m), 3... Mass spectrometry part, 5... Accelerator tube,
7...X deflection electrode pair, 8...YB deflection electrode pair 10.
... Substrate, 1] ... Implantation chamber, 12 ... Ion beam, 71 ... First electrode pair, 72 ... Second electrode pair, 81 ... First magnetic pole pair, 82 ...second magnetic pole pair,
104... Acceleration section, 107... Deflection section. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1) A plasma generation section that turns the introduced raw material gas or metal vapor into plasma, an ion extraction section that extracts ions with a specific polarity from the plasma in this plasma generation section, and a An ion beam consisting of predetermined ions is generated using a mass spectrometer that extracts only ions with a specific charge/mass ratio from the inside, and an accelerator that gives a predetermined kinetic energy to the ions extracted by the mass spectrometer. through a deflection unit that scans the ion beam two-dimensionally in two directions perpendicular to the traveling direction of the beam and at right angles to each other,
In an ion beam device that guides ions into an implantation chamber that holds a substrate to be irradiated and implanted, and irradiates and implants ions onto the surface of the substrate, the deflection unit directs the ion beam in two orthogonal directions. A first electrode pair that deflects the ion beam in one direction, a second electrode pair that deflects the deflected ion beam in the same direction as the traveling direction before deflection, and a second electrode pair that deflects the ion beam in one direction. The first deflected in the direction of
and a second magnetic pole pair that deflects the deflected ion beam in the same direction as the traveling direction before deflection, and the first electrode pair is arranged inside the first magnetic pole pair. An ion beam device characterized in that the second electrode pair is arranged inside the second magnetic pole pair.