JP2009299129A - Vacuum vapor deposition apparatus, and electronic beam irradiation method of the apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum vapor deposition apparatus which can perform vapor deposition at an always high vapor deposition rate, and nevertheless does not give damage to a semiconductor substrate to be subjected to vapor deposition, and does not give rise to curing of a photoresist, and an electron beam irradiation method of the vacuum vapor deposition apparatus. <P>SOLUTION: The vacuum vapor deposition apparatus 10 includes: a substrate holder for holding a semiconductor substrate 24; an electron beam generating means for irradiating an evaporation material with an electron beam 17 to cause evaporation; a beam orbit control means for controlling the orbit of the electron beam 17 in order to project the electron beam 17 on the evaporation means; a vapor deposition rate detection means for detecting the vapor deposition rate of the thin film vapor deposited on the semiconductor substrate 24; a high vapor deposition rate position calculate means for calculating the high vapor deposition rate position at which the vapor deposition rate higher than the above described vapor deposition rate can be obtained when the vapor deposition rate is reduced; and a beam orbit correction means for correcting the orbit of the electron beam 17 in such a manner that the high vapor deposition rate position of the vapor deposition material is irradiated with the electron beam 17. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vacuum vapor deposition apparatus used in a semiconductor manufacturing process, and more particularly to an electron beam heating type vacuum vapor deposition apparatus heated by an electron beam and an electron beam irradiation method of this apparatus.

  One type of vacuum vapor deposition apparatus used in semiconductor manufacturing processes is an electron beam heating method that can input a very large power density into an evaporation source (see Patent Document 1). This type of vacuum deposition apparatus is widely used, for example, for forming electrodes of GaAs power FETs (power effect transistors).

  In this apparatus, a metal, for example, an aluminum (Al) or platinum (Pt) evaporation source is irradiated with an electron beam, and a vaporized molecular stream of the metal is applied to an upper semiconductor substrate to form a film such as an electrode. Do.

  The evaporation source is usually put in an evaporation source container, and irradiation of the electron beam to the evaporation source is controlled by correcting the trajectory of the electron beam emitted from the filament by an electromagnetic magnet.

  Conventionally, the irradiation position of the electron beam to the evaporation source is determined in advance by performing a vapor deposition operation on a dummy during maintenance of the vacuum evaporation apparatus and confirming the irradiation position of the electron beam with human eyes. -The Y-axis electromagnetic magnet was adjusted. Therefore, when performing actual vapor deposition, the irradiation position of the electron beam is fixed. When a high electron beam is output, for example, by increasing the vapor deposition rate, only the evaporation material at the irradiation position evaporates and the container is also dissolved. As a result, the container became a mortar shape, and there was a problem that stable vapor deposition could not be performed.

  As a method for solving this problem, there is a method of uniformly irradiating an evaporating material with an electron beam by scanning the electron beam irradiated on the evaporating material with a certain frequency and amplitude in the XY directions. According to this method, an electron beam is not applied to only a part of the evaporation material, and a stable evaporation molecular flow can be generated. However, in this method, the deposition rate is extremely reduced, and a higher-power electron beam is required. When this happens, the amount of heat generated from the electron beam, recoil electrons and secondary electrons emitted from the evaporation material increases, causing problems such as damage to the semiconductor substrate and hardening of the photoresist.

A technique is known in which the evaporation source is modeled by a plurality of minute planar evaporation sources, and the film thickness distribution of the thin film formed on the substrate is calculated by a predetermined formula (see Patent Document 2).
JP-A-2-61059 Japanese Patent Laid-Open No. 2001-140058

  The present invention has been made in view of the problems of the conventional vacuum deposition apparatus as described above, and can always perform deposition at a high deposition rate. Moreover, the present invention can damage a semiconductor substrate on which deposition is performed, It is an object of the present invention to provide a vacuum deposition apparatus and an electron beam irradiation method for the apparatus that do not cause curing of the apparatus.

According to claim 1 of the present invention, the substrate holder for holding the semiconductor substrate, the electron beam generating means for irradiating the evaporation material with the electron beam and evaporating, and the evaporation material is irradiated with the electron beam. A beam trajectory control means for controlling the trajectory of the electron beam, a vapor deposition rate detection means for detecting the vapor deposition rate of the thin film deposited on the semiconductor substrate, and a vapor deposition rate higher than the vapor deposition rate when the vapor deposition rate decreases. High vapor deposition rate position calculating means for calculating a high vapor deposition rate position of the vapor deposition material, and beam trajectory correction for correcting the electron beam trajectory so that the electron beam is irradiated to the high vapor deposition rate position of the vapor deposition material. Means,
There is provided a vacuum evaporation apparatus characterized by comprising:

  According to the present invention, it is possible to carry out vapor deposition at a high vapor deposition rate at all times, and it does not damage the semiconductor substrate on which vapor deposition is performed or cause hardening of the photoresist, and electron beam irradiation of this device. There is an effect that the method is obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an overall configuration of an embodiment of the present invention. The vacuum deposition apparatus 10 includes a deposition chamber section 12 that generates a deposition molecular stream 11 from an evaporation source and deposits it on a semiconductor substrate (wafer), and an electron beam power supply section 13 that supplies power to a filament that creates an electron beam at the evaporation source. And a high vacuum pump unit 14 for evacuating the inside of the vapor deposition chamber unit 12.

  The vapor deposition chamber section 12 is evacuated by a high vacuum pump section 14, in which an evaporation source 16 on which the evaporation material 15 is placed, a filament 18 that generates an electron beam 17 that irradiates the evaporation material 15, and this A trajectory control electromagnetic magnet 19 for controlling the trajectory of the electron beam 17 irradiated from the filament 18, an electron beam shutter 21 for controlling the interruption of the electron beam 17 irradiated to the evaporation material 15, and a rotating shaft above the evaporation source 16. And a film thickness monitor 25 for detecting the thickness of a thin film formed on the semiconductor substrate 24 held by the dome disk substrate holder 23.

  The trajectory control electromagnetic magnet 19 is connected to an electronic computer (personal computer) 27 so that the trajectory of the electron beam 17 can be controlled in the X and Y directions. As will be described later, the movable range of the X- and Y-axes of the electron beam 17 and the necessary minimum deposition rate Ri are input to the electronic computer 27.

  On the other hand, during the deposition process, the deposition rate on the semiconductor substrate 24 is detected by the film thickness monitor 25, and the deposition rate is input to the electronic computer 27 every moment. When the detected deposition rate falls below the required minimum deposition rate Ri, the deposition rate is calculated for a plurality of beam irradiation candidate positions of the evaporation material 15 by the response surface method, and the electron beam irradiation position at which the deposition rate is maximized is obtained. Thus, the trajectory of the electron beam 17 is corrected so that the electron beam 17 is irradiated to the position.

  FIG. 2 shows a view of the dome disk-type substrate holder 23 as viewed from below. As shown in the figure, the dome disk-shaped substrate holder 23 includes a plurality of semiconductor substrates 24 arranged in a concentric circular shape, and a rotating shaft 22 provided at the center of the dome disk-shaped substrate holder 23. Rotate to center. The semiconductor substrate 24 is placed on the dome disk-type substrate holder 23 so as to be perpendicular to the evaporated molecular flow 11 emitted from the evaporation material 15.

  Next, operation | movement of the vacuum evaporation system 10 of this embodiment is demonstrated. First, the semiconductor substrate 24 is installed in the dome disk-shaped substrate holder 23, and the vapor deposition chamber unit 12 is put into a high vacuum state by the high vacuum pump unit 14.

  As shown in FIG. 3, in step S <b> 301, the X-axis and Y-axis movable ranges of the electron beam 17 with respect to the evaporation source 16 and the semiconductor substrate 24 are connected to the computer 27 connected to the orbit control electromagnetic magnet 19. The minimum required deposition rate Ri is set by inputting.

  In step S302, the electronic calculator 27 sets, for example, nine optimum positions 31a, 31b, 31c, and 31d for detecting the optimum position for electron beam irradiation on the evaporation material 15 as shown in FIG. , 31e, 31f, 31g, 31h, 31i are determined.

  In step S <b> 303, the electron beam power supply unit 13 is operated to energize the filament 18 to correct the trajectory of the electron beam 17 and irradiate the evaporation material 15. At the initial value, for example, the trajectory is controlled so that the electron beam 17 is irradiated to the beam optimum condition detection position 31a shown in FIG.

  In step S304, the evaporation molecular flow 11 generated by the electron beam irradiation is applied to the semiconductor substrate 24 to perform a vapor deposition process. At the same time, the deposition rate on the semiconductor substrate 24 is monitored by the film thickness monitor 25 in step S305. All of these controls are performed by the electronic computer 27. Detection of the deposition rate by the film thickness monitor 25 is performed by converting the deposition rate from the vibration frequency of the crystal in the evaporation source 16.

  In the next step S306, it is detected whether the vapor deposition is completed based on the film thickness. If the vapor deposition is not yet completed, it is detected in step S307 whether the vapor deposition rate is lower than the necessary minimum vapor deposition rate Ri. When the deposition rate is not lower than the necessary minimum deposition rate Ri, the process returns to step S304 to continue the deposition process, and the deposition rate is monitored in step S305.

  On the other hand, if the deposition rate is lower than the necessary minimum deposition rate Ri, partial regression analysis is performed in step S308 based on, for example, the response surface method of the experimental design method. The analysis by the response surface method is also automatically performed by the electronic computer 27.

  In the next step S309, the beam irradiation optimum position at which the vapor deposition rate becomes the maximum value is determined. Then, returning to step S303, the trajectory of the electron beam 17 is corrected so that the evaporating material 15 at that position is irradiated with the electron beam 17, and vapor deposition is performed again in step S304. In this way, the electron beam is always irradiated to an appropriate position of the evaporation material so that a high vapor deposition rate can be obtained.

  As a specific example, consider the case where aluminum (Al) is vapor-deposited by a vapor deposition apparatus of company A. For example, the necessary minimum deposition rate Ri is set to 80 Å / second, and the movable ranges of the X axis and the Y axis are each ± 10 mm.

  In this case, nine beam optimum condition detection positions and the resulting deposition rate (Å / sec) are as shown in FIG. In FIG. 5, the value of X, Y may be ± 14.421 because it is the distance from the center of the evaporation source 16.

This equation is assumed as a function Z = f (X, Y) by the response surface method from the deposition rate with respect to the X and Y values in FIG. The partial regression coefficient for each deposition rate at that time is obtained by the method of least squares. The constants, X, Y, X ² , Y ² , and XY coefficients are as shown in FIG.

  When the result of the above equation is plotted by the contour lines of the deposition rate and the values of X and Y, it is as shown in FIG. Further, when the relationship between the deposition rate and the values of X and Y is plotted on a curved surface, it is as shown in FIG.

  When the position of the maximum value of the curved surface in FIG. 7B is obtained, it is as shown in FIG. 8, and X = −5.56 mm and Y = + 1.79 mm, and the maximum deposition rate is obtained at this position. A deposition rate of 82.33 ８２ / sec can be expected.

  According to this embodiment, when the vapor deposition rate decreases, the position of the evaporation material having a large vapor deposition rate is automatically determined, and the trajectory of the electron beam is corrected so as to irradiate the position with the electron beam. Therefore, it is possible to always perform the vapor deposition process at an optimum rate.

  In the above embodiment, nine beam optimum condition detection positions are used, but in the present invention, beam optimum condition detection positions of 10 points or more or 8 points or less may be used.

  In the above embodiment, the position of the deposition rate is determined by the partial regression analysis of the response surface method, and the electron beam trajectory is corrected so that the electron beam is irradiated to the position. However, in the present invention, it is only necessary to irradiate the evaporation material at a position where a deposition rate higher than the necessary minimum deposition rate can be obtained even if the deposition rate does not become the maximum value.

  In the above-described embodiment, the position of the evaporation material at which a deposition rate higher than the required minimum deposition rate is obtained by the response surface method. However, in the present invention, the position of the evaporating material that can obtain a vapor deposition rate higher than the required minimum vapor deposition rate may be obtained without using the response surface method.

  The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the technical idea, and these are also included in the scope of the present invention.

The figure which shows the whole structure of the vacuum evaporation system of one Embodiment of this invention. The figure which shows the structure of the dome disk type | mold board | substrate holder 23 in the vacuum evaporation system of this embodiment. The figure for demonstrating operation | movement of the vacuum evaporation system of this embodiment. The figure for demonstrating the beam optimal condition detection position in the vacuum evaporation system of this embodiment. The figure which shows the relationship between a beam optimal condition detection position, and the vapor deposition rate at that time. The figure which shows each coefficient which calculated the function by the response surface method when the vapor deposition rate shown in FIG. 5 was obtained. The figure which plotted the contour line and curved surface of a vapor deposition rate, X, and Y value. The figure which shows the X and Y value from which a vapor deposition rate becomes the maximum value.

Explanation of symbols

10 ... Vacuum evaporation apparatus,
12: Deposition chamber part,
13 ... Electron beam power supply unit,
14 ... High vacuum pump section,
15 ... evaporation material,
16 ... evaporation source,
17 ... electron beam,
18 ... Filament,
19 ... Orbit control electromagnetic magnet,
21 ... Electron beam shutter,
22 ... rotating shaft,
23: Dome disk type substrate holder,
24 ... Semiconductor substrate,
25 ... Film thickness monitor,
27 ... an electronic computer,
31a, 31b, 31c, 31d, 31e, 31f, 31g, 31h, 31i ... Beam optimum condition detection position.

Claims (6)

A substrate holder for holding a semiconductor substrate;
An electron beam generating means for irradiating the evaporation material with an electron beam and evaporating;
Beam trajectory control means for controlling the trajectory of the electron beam so that the electron beam is irradiated onto the evaporation material;
A deposition rate detecting means for detecting a deposition rate of a thin film deposited on the semiconductor substrate;
A high vapor deposition rate position calculating means for calculating a high vapor deposition rate position of the vapor deposition material from which a vapor deposition rate higher than the vapor deposition rate is obtained when the vapor deposition rate is reduced;
Beam trajectory correcting means for correcting the trajectory of the electron beam so that the electron beam is irradiated to the high vapor deposition rate position of the vapor deposition material;
A vacuum evaporation apparatus characterized by comprising: A substrate holder for holding a semiconductor substrate;
An electron beam generating means for irradiating the evaporation material with an electron beam and evaporating;
Beam trajectory control means for controlling the trajectory of the electron beam so that the electron beam is irradiated onto the evaporation material;
A deposition rate detecting means for detecting a deposition rate of a thin film deposited on the semiconductor substrate;
When the deposition rate is lower than the necessary minimum deposition rate, the deposition rate of the deposition material is higher than the necessary minimum deposition rate by the response surface method based on the plurality of beam optimum condition detection positions of the evaporation material. High vapor deposition rate position calculating means for calculating a high vapor deposition rate position of the obtained vapor deposition material;
Beam trajectory correcting means for correcting the trajectory of the electron beam so that the electron beam is irradiated to the high vapor deposition rate position of the vapor deposition material;
A vacuum evaporation apparatus characterized by comprising:   The vacuum deposition apparatus according to claim 2, wherein the high deposition rate position calculating means calculates the high deposition rate position by a partial regression analysis of a response surface method.   The vacuum deposition apparatus according to claim 3, wherein the beam optimum condition detection positions are nine points.   The high vapor deposition rate position calculating means calculates a high vapor deposition rate position of the vapor deposition material that can obtain the highest vapor deposition rate by a response surface method based on a plurality of beam optimum condition detection positions of the vaporized material. The vacuum evaporation apparatus according to claim 4, wherein the apparatus is a vacuum evaporation apparatus. An electron beam irradiation step of irradiating the evaporation material with an electron beam and evaporating;
A beam trajectory control step for controlling the trajectory of the electron beam such that the electron beam is irradiated to the evaporation material;
A deposition rate detecting step for detecting a deposition rate of a thin film deposited on the semiconductor substrate;
When the deposition rate is lower than the necessary minimum deposition rate, the deposition rate of the deposition material is higher than the necessary minimum deposition rate by the response surface method based on the plurality of beam optimum condition detection positions of the evaporation material. A high vapor deposition rate position calculating step for calculating a high vapor deposition rate position of the obtained vapor deposition material;
A beam trajectory correcting step for correcting the trajectory of the electron beam so that the electron beam is irradiated to the high vapor deposition rate position of the vapor deposition material;
An electron beam irradiation method for a vacuum evaporation apparatus, comprising:

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