JPS61281882A - Dry thin film processing equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

A FL film processing apparatus for growing or etching a thin film on a substrate, the apparatus comprising: a means for generating microwaves; a means for transmitting the microwaves; is introduced, and is provided with means for generating magnetic lines of force that turn gas into plasma through the resonance effect with the microwaves to produce one active atom molecule or ion, and whose axis line coincides with the central axis of the magnetic flux generated by the magnetic line of force generating means. a metal container having an opening on a side facing the microwave transmission means; and a metal container that is coupled to the metal container through the opening and flows out from the opening along the magnetic flux by one molecule of the active atom or ion. The present invention relates to a dry thin film processing apparatus including a reaction tank in which a substrate on which a thin film is formed or etched is disposed perpendicularly intersecting the central axis of the magnetic flux.

[Prior art and its problems]

In the technical field to which this invention pertains, process technology using EcR plasma has recently attracted attention. What is ECR [! 1ectron Cyclotron Re5on
ance (electron cyclotron resonance), which accelerates electrons using the resonance effect of a magnetic field and microwaves, and uses the kinetic energy of the electrons to ionize gas to obtain plasma. Electrons excited by microwaves move circularly around magnetic lines of force, and the condition where centrifugal force and Lorentz force are balanced is called the ECR condition. The centrifugal force is −rω2. If we express the Lorent force by -qrωB, then
The condition for these to be balanced is ω/B=q/mackerel. Here, ω is the angular velocity of the microwave, B is the magnetic flux density, and q/− is the specific charge of the electron. The microwave frequency generally used is 2)45GH2, which is accepted for industrial use, and in that case, the resonant magnetic flux density is 0.08757. The behavior of electrons under ECR conditions is as follows. As shown in Fig. 3, let us assume that an alternating electric field E is applied in the y direction and a static magnetic field B is applied in two directions. In this case, the equation of motion is (with ωc = q/m B), t
−・−−−−−・−・■ql! 9-- sin ωc1 + ωC large・---m−-・■The above equation is t-o′T! Thick-u, -u N, , 7-u
, -u,. Solving as, Thick 11++ 1J Ifm uII・(Q3 ωct
uyoNn ωct2ωC Y ” ' y ” u wo3anωc L + u
yoeo! ωet Furthermore, at t-Q, X = ” o, Y
Integrating the above equation as -Y o, 1 qE7m xmx, +-5lnωcl+ (uy.+ -)
(cosωct-1) aICQCtdC 2ω. ωCωc2ωC 2ωC The last term in the above equation becomes the main term after enough time, the charged particles draw a circular orbit while increasing the radius, and the electron velocity increases continuously in a complete vacuum. In reality, electrons collide with other particles, so the radius of the electron never becomes infinite. However, since collisions occur through stochastic processes, the energy of the electron is distributed over a very wide range, and a small number of high-energy electrons The zero-rotating electron that results in the unavoidable mixture of magnetic moments μ−qr ω
/2, F, -Z Collisions and, together with active species, causes substrate processing, but if the electrons possess too much energy, it will naturally cause damage to the thin film on the substrate. . A known example of ECR plasma restoration is a method in which a device as shown in FIG. 4 is operated with a magnetic field distribution as shown in FIG. 5. With this device,
The metal container 39 reaction tank 9 is evacuated and the gas population is 4.
The microwave is passed through the waveguide l to where the gas from h flows into the metal container 3. A metal plate 7 with a large-diameter hole in the center is attached to the lower part of the metal container 3, which is fed into the metal container 3 through the vacuum window 2, and this metal plate and the metal container 3 combine to form a semi-open micro It constitutes a wave resonator. A solenoid 6 is disposed outside this resonator and generates a magnetic field having a magnetic flux density cross-sectional distribution shown in FIG. 5 within the resonator, so that ECR plasma is generated. Silane gas (SLlle) is sent from the gas population 12 into the space where this plasma is pushed out to the reaction tank 9 and goes toward the sample stage 10, and when this gas is activated by the plasma, the generated active species react with the substrate 11. A thin film is formed on the surface of the substrate 11. This apparatus can also be used for etching substrates by flowing an etching gas from gas population 4 instead of the N-rich gas. As mentioned above, the mechanism by which plasma is sent out from the large diameter hole of the metal plate 7 in this conventional device is due to the interaction between the magnetic dipole moment and the magnetic field. is fostering problems that are indeterminate, and therefore,
The electron translational energy stochastically has an extremely large value, which has the disadvantage of damaging semiconductor circuit elements on the substrate. Another known example of an ECR plasma apparatus is a method in which an apparatus as shown in FIG. 6 is operated with a magnetic flux distribution as shown in FIG. 7. In this method, microwaves generated by a magnetron 41 are transferred to a waveguide 4.
The inside of the quartz tube 449 reaction tank 47 is injected into the quartz tube 44 through the gas inlet 46, and the inside of the reaction tank 47 is evacuated in advance. Magnetic lines of force having a magnetic flux density cross-sectional distribution as shown in Fig. 7 are generated inside the quartz tube, and gas is turned into plasma by interaction with microwaves. This plasma reaches the surface of the substrate 49, active species in this plasma react with the surface of the substrate 49, and etching progresses. Even in this conventional method, μ
The value of is indeterminate, and therefore the translational energy of electrons has a probability of being extremely large, which not only has the disadvantage of damaging the semiconductor circuit elements being processed on the substrate.
In this conventional device, the magnetic flux density in most parts of the interior of the quartz tube is much higher than that under ECR conditions, and therefore, as will be revealed later, electron heating cannot be performed efficiently, and as a result, the etching rate decreases. The drawback was that it was extremely low.

[Purpose of the invention]

The present invention aims to eliminate the drawbacks of the conventional microwave ECR plasma apparatus described above, and to provide an etching apparatus or thin film growth apparatus that realizes a large-diameter, uniform-velocity plasma flow, is free from damage, and has a high reaction rate. purpose.

Summary of the Invention The present invention provides a means for generating microwaves, a means for transmitting the microwaves, and a means for introducing the microwaves by being coupled with the microwave transmitting means, and a resonance effect with the microwaves. means for generating magnetic lines of force that turn gas into plasma to produce one molecule of active atoms or ions, and an opening whose axis is aligned with the central axis of the flux of magnetic lines of force generated by the line of magnetic force generating means is opposite to the microwave transmitting means. A thin film is generated or etched on the surface by a metal container held on the side, and the active atom molecule or ion that is coupled to the metal container through the opening and flows out from the opening along the magnetic flux. In a dry thin film processing apparatus comprising a reaction tank in which a substrate is disposed to intersect perpendicularly to the central axis of the magnetic flux, the reaction tank surrounds the substrate and directs magnetic flux lines that intersect substantially perpendicularly to the surface of the substrate into the magnetic flux. A solenoid is provided that generates energy in cooperation with a generation means, and a magnetic flux that resonates with the microwave changes the magnetic flux density of the magnetic lines of force that exist between the opening position in the reaction tank and the substrate surface position and in the metal container. By setting the density to be less than that, the above object is attempted to be achieved. This Nezashi will be explained in detail below. Now, let's consider the movement of electrons when the microwave frequency deviates from the E C, R condition. Assume that a static magnetic field B and an alternating electric field E are applied in the directions shown in Figure 3. In this case, The equation of motion is father--ωc9...
−・・・・・・・−・・■E 9wz−sin ω t + ω. Big ·
-・---・■ Here, ωC is the frequency of the microwave that resonates with the given static magnetic field B, and ω is the frequency of the microwave injected into this static magnetic field. The above formula is 1-0, thick-u
x ” u”' 小-u, a u,. Solving as
u , mu , , cosωc t −uyo sin
ωc1−・・−・・−・−・−・−■ u v ” u x@sin ωc j' +
u yecOa IJ c further t-
0 and the product ω as 1-Xo+Y-To.
ω. ωωCω.
ωCω2−ωc1 sina+ct alnωt x (----→ ---・[phase] ωCω In the above equation, the main term is only the last term, so here,
If we set ωC/ω-1-δ, then from the above formula -・-・−・−・
[Phase] If δ<1 at ω and ω, then the above equation ignores the second term and becomes x 5in-(63+(13c) t -・-=-4
xcos(ω+ωc) t ”−'−・・−・・−[
The locus described by the above equation, which is [phase], rotates at the higher frequency (ω÷ω,)/4π, and its radius changes sinusoidally at the lower frequency (ω-ωc)/4π. It is a circular orbit. There is a maximum radius of this circular orbit. On the other hand, if ω/ωc<<1, then from the 0 formula, ωC qtl/m Swamp □ Possible ωt ・・−−・−・ωωC Also, from the [phase] formula, ωC qH/m Swamp □ sin ω1 −・− - [Yes] ωC8 Therefore, in this case, it becomes an ellipse with the angular frequency ω and the principal axis in the X-axis direction. The ratio of the short axis to the long axis is ω/ω. and
A ripple with a cyclotron angular frequency ω is superimposed on this elliptical motion. This corresponds to a case where the magnetic flux density is sufficiently larger than the ECR condition, and in this case, the electron orbit radius is not indefinite, but its value is small. Finally, in the case of ωC/ωg1, from equation 0, ω”(1−
-) ω3 ωωC Also, from equation 0, the main motion in the case of ω1(1--”) ω8 ωω is a circular motion with a low frequency ω, and furthermore, an elliptical motion with a frequency ω is superimposed, resulting in ω ω C ωC. This corresponds to a case where the magnetic flux density is sufficiently smaller than the ECR condition, and the radius of rotation in this case is small.If ω deviates significantly from ωG in this way, electrons absorb microwaves and have the effect of increasing rotational energy. Considering the radius of motion of electrons from the above discussion, in order for electrons to be effectively heated, ωYω. In other words, the frequency of the microwave and the size of the magnetic flux density are ECR conditions: ω/B
It can be seen that the condition is that -e/m is approximately satisfied. The maximum number of electrons generated in this way is μ(B□x
-Bo) collides with the substrate with a translational energy of -Bo). Here B, 1. is the maximum magnetic flux density of the plasma chamber, and Bo is the magnetic flux density of the substrate surface. In order for this translational energy to be large enough to increase the machining speed and within limits that do not cause damage, it is effective to make the magnetic flux density distribution into the shape shown in Figure 2, that is, an asymmetric mirror magnetic field. . However, the magnetic flux density, that is, the microwave frequency of 2.45 GII, satisfies the perfect ECR condition, where μ is undefined and can take an extremely large value probabilistically. When 875 Gauss exists in the plasma chamber, the translational energy of the electrons becomes indeterminate, and it is inevitable that high-speed electrons will collide with the substrate with a certain probability. Therefore, in order to avoid such a phenomenon, it is necessary to It is sufficient to limit the magnetomotive force of the solenoid so that the magnetic flux density does not satisfy the perfect ECR condition anywhere in the room.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the main parts of a dry thin film processing apparatus constructed based on the present invention, in which, in addition to the configuration of the conventional method shown in FIG. 69
A solenoid 73 is arranged on the outer circumferential side of the solenoid 73.
A mirror magnetic field having a plasma confinement effect is formed in the reaction tank between the position of the solenoid 66 and the position of the solenoid 66, which is a conventional magnetic line generating means. In this case, the magnetic flux density inside the metal container 63 due to the magnetomotive force of the solenoid 66 is close to the ECR condition, as shown in FIG.
Make the magnetic flux density smaller than the one that satisfies the CR condition. An excitation current is supplied to the solenoid 73 to generate magnetic lines of force on the substrate surface, and the excitation current is adjusted so that the vector sum of the magnetic lines of force and the lines of magnetic force generated by the solenoid 66 is perpendicular to the substrate surface. At this time, the magnetic flux density on the substrate surface is determined by the solenoid 66.7 while maintaining the magnetic field lines perpendicular to the substrate.
3, the distance from the opening 63a of the metal container 63 to the substrate surface, or the relative axial position of the solenoid 73 with respect to the substrate 72, or a combination thereof, and also adjust the magnetic flux within the metal container 63. The plasma density is set to be appropriately smaller than the density so that the plasma is incident on the substrate surface with appropriate energy.

【Effect of the invention】

As described above, according to the present invention, in addition to the conventional dry thin film processing apparatus using microwave ECR plasma, a solenoid 73 is newly arranged in the reaction tank, and the opening position of the end of the metal container and the substrate surface are A mirror magnetic field having a plasma confinement effect is formed between the substrate position and the magnetic field lines on the substrate surface by adjusting the substrate position, the excitation current of the solenoids 66 and 73, or the relative axial position of the substrate and the solenoid 73. It intersects the board perpendicularly and at an appropriate value, and the magnetic flux density is set to be smaller than the magnetic flux density of the ECR condition at any location, so complete EC is achieved.
The generation of high-energy electrons that can occur under R conditions can be suppressed, and as a result, the speed of longitudinal shift of electrons due to changes in the longitudinal component of magnetic flux density can be controlled, and
Since the plasma can be incident on the substrate surface at an appropriate speed, a thin film processing device that does not damage the substrate and has a high processing speed has become possible.

[Brief explanation of drawings]

1 is an explanatory cross-sectional view showing an embodiment of the main parts of a dry thin film processing apparatus constructed based on the present invention, FIG. 2 is an explanatory view showing the magnetic flux density distribution of each part of the apparatus of FIG. 1, and FIG. The figure is a diagram defining the respective directions of the magnetic field and electric field for ECR plasma generation, which was set when theoretically supporting the present invention, and Figure 4 shows an example of the configuration of a conventional dry thin film processing apparatus. 5 is an explanatory diagram showing the magnetic flux density distribution of each part in the apparatus shown in FIG. 4; FIG. 6 is a sectional view of the main part showing another example of the configuration of the conventional dry thin film processing apparatus; FIG. 7 is an explanatory diagram showing the magnetic flux density distribution of each part in the device of FIG. 6. FIG. 1.42.43.61: Waveguide, 3.63: Metal container, 3a. 63a; opening, 6.45.66: solenoid, 9.4
7.69 + reaction tank, 11.49.72: M plate, 7
3: Solenoid. Microsimetry ratio - Fig. 1 Fig. 2 ↓ Vacuum system Fig. 4 Fig. 5

Claims (1)

[Scope of Claims] 1) A means for generating microwaves, a means for transmitting the microwaves, and a means for transmitting the microwaves, which is coupled to the microwave transmitting means to introduce the microwaves, and has a resonance effect with the microwaves. A means for generating magnetic lines of force for generating active atoms, molecules or ions by turning gas into plasma is provided, and an opening whose axis coincides with the central axis of the flux of magnetic lines of force generated by the means for generating lines of magnetic force is provided on the side opposite to the microwave transmitting means. a metal container having a metal container, and a substrate on which a thin film is generated or etched by the active atoms, molecules or ions that are coupled to the metal container through the opening and flow out from the opening along the magnetic flux. In a dry thin film processing apparatus comprising a reaction tank disposed perpendicularly intersecting the central axis of the magnetic flux, the reaction tank surrounds the substrate and generates magnetic flux lines that intersect substantially perpendicularly with the surface of the substrate. and a solenoid that generates the magnetic flux density between the opening position in the reaction tank and the substrate surface position and in the metal container so that the magnetic flux density is lower than the magnetic flux density that resonates with the microwave. This dry thin film processing equipment is characterized by: 2) In the apparatus according to claim 1, magnetic lines of force that intersect perpendicularly to the surface of the substrate and have a magnetic flux density lower than the magnetic flux density that resonates with microwaves are connected to a solenoid surrounding the substrate and disposed in the reaction tank. Excitation current supplied;
The electric power supplied to the magnetic field line generating means that generates the magnetic field lines that turn gas into plasma, the distance of the substrate from the opening of the metal container, and the axis between the substrate and the solenoid surrounding the substrate and arranged in the reaction tank. 1. A dry thin film processing apparatus characterized in that the processing is performed by changing at least one of the direction and relative position.