JP2009041040A - Vacuum vapor deposition method and vacuum vapor deposition apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the deposition property of a vapor-deposited film on a side surface and a bottom surface of a via hole. <P>SOLUTION: A vacuum vapor deposition apparatus 10 comprises a vacuum chamber 11, an evaporation source 13 installed in the vacuum chamber, a stage 15 arranged opposite to the evaporation source, a rotating means 18 for rotating the stage in the plane, and an angle adjustment means 19 for changing the installation angle of the stage with respect to the evaporation source. Evaporated particles are deposited on a surface of a substrate while turning the substrate W in the plane, and changing the angle of inclination of the substrate with respect to the evaporation source so that the angle of incidence of the evaporated particles with respect to the surface of the substrate is continuously changed. The deposition property of a vapor-deposited film on a side surface and a bottom surface of a veer can be enhanced irrespective of the radial position of the substrate. Thus, the coverage characteristic of the vapor-deposited film in the substrate plane can be unified. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vacuum vapor deposition method and a vacuum vapor deposition apparatus that improve an adhesion property (coverage property) of a vapor deposition film to a side surface and a bottom surface of a via formed on a substrate surface.

  As a method for forming a seed layer for wet plating (electroplating) in a via hole of a semiconductor circuit or a flexible wiring board, for example, a sputtering method such as a low pressure long throw sputtering (LTS) method having a long target-substrate distance is known. (See Patent Document 1).

  However, in the sputtering method, the metal film is less likely to be attached to the bottom and side surfaces of the via hole, and the ratio of the metal film deposited on the substrate surface to the film thickness (hereinafter referred to as the “attachment ratio”) is very low at 2-3%. . This is due to the large incident angle of sputtered particles incident on the substrate from the target in the sputtering method. For example, when a 0.1 μm seed layer is to be formed on the side surface of a via hole having an aspect ratio of 2, it is necessary to form a seed layer metal film to 3.3 to 5.0 μm on the substrate surface. Further, in the three-dimensional mounting of LSI or the like, it is necessary to remove the metal layer formed on the substrate surface by etching or the like. Therefore, the thicker the metal layer on the surface, the more labor and time are required.

  On the other hand, a vacuum vapor deposition method is known in which a substrate is disposed obliquely with respect to an evaporation source and vapor deposition is performed while rotating the substrate (see Patent Document 2). As shown in FIG. 5, the vacuum chamber 1 includes an electron beam evaporation source 2 and a dome-shaped holder 3 that holds a plurality of substrates W. A plurality of holders 3 are installed on the planetary 6 and are held obliquely with respect to the electron beam evaporation source 2. The planetary 6 is provided with a revolving mechanism 4 for revolving the holder 3 and a revolving mechanism 5 for revolving the holder 3. During evaporation, the evaporation particles Ma of the evaporation material M are deposited on the surface of the substrate W while rotating and revolving the holder 3. As a result, film formation with excellent in-plane uniformity is realized on the substrate W.

JP 2000-260770 A JP 2002-164303 A

  In the vacuum deposition method, the evaporation material evaporated by the evaporation source that can be regarded as a point source is incident on the surface of the substrate with a certain spread, and therefore the incident angle of the evaporated particles with respect to the substrate varies depending on the position on the substrate. Moreover, even if film formation is performed while rotating and revolving the planetary 6 as in the conventional vacuum vapor deposition apparatus described above, the incident angle distribution corresponding to the position on the substrate (radial position in the case of a circular substrate) can be eliminated. I can't.

  Therefore, when a metal film is formed on a via hole formed on the substrate surface, the metal film coverage with respect to the side and bottom surfaces of the via hole varies depending on the position on the substrate. There is a problem that can not be.

  The present invention has been made in view of the above-described problems, and it is an object of the present invention to provide a vacuum vapor deposition method and a vacuum vapor deposition apparatus that can improve the adhesion of a vapor deposition film to the side and bottom surfaces of a via regardless of the position on the substrate. And

  In solving the above problems, the vacuum vapor deposition method of the present invention is a vacuum vapor deposition method in which evaporated particles from an evaporation source are deposited on the surface of a substrate in which a recess such as a via or a trench is formed in a vacuum chamber. Evaporating particles on the surface of the substrate while rotating the substrate in the plane of the surface and changing the tilt angle of the substrate with respect to the evaporation source so that the incident angle of the evaporating particles on the surface of the substrate continuously changes It is characterized by depositing.

  In addition, the vacuum vapor deposition apparatus of the present invention includes a vacuum chamber, an evaporation source installed in the vacuum chamber, a stage disposed opposite to the evaporation source, and a rotating unit that rotates the stage within the plane of the stage surface. And an angle adjusting means for changing the installation angle of the stage with respect to the evaporation source, wherein the angle adjusting means continuously changes the incident angle of the evaporated particles with respect to the surface of the substrate on the stage during vapor deposition. To do.

  In the present invention, the substrate is rotated on the surface of the substrate, and the inclination angle of the substrate is changed with respect to the evaporation source so that the incident angle of the evaporation particles to the substrate surface continuously changes. By depositing the evaporated particles, it is possible to increase the deposition property of the deposited film with respect to the side surface and the bottom surface of the concave portion regardless of the position on the substrate. Accordingly, the coverage characteristics of the vapor deposition film can be made uniform in the substrate plane.

  The tilt angle, tilt moving speed, rotation speed, etc. of the substrate with respect to the evaporation source are appropriately set according to the aspect ratio of vias formed on the substrate surface, the size of the substrate, the incident angle distribution of the evaporated particles, etc. The tilt angle control or the rotation control of the substrate is performed under the condition that a desired coverage ratio is obtained for each of the vias. The substrate may be a circular substrate or a rectangular substrate. The center of rotation in the plane of the substrate is not limited to the central portion of the substrate, and may be any other point in the plane.

On the other hand, by adjusting the inside of the vacuum chamber to an inert gas atmosphere under reduced pressure at the time of vapor deposition, the effect of scattering of evaporated particles between gas molecules is used to further improve the ability to wrap around the side and bottom of the via. Improvements can be made. An example of the inert gas is argon (Ar). The atmospheric pressure is preferably 2.0 × 10 ⁻² Pa or more and 8.0 × 10 ⁻² Pa or less.

  The number of stages installed in the vacuum chamber is not limited to one and may be plural. In this case, by performing the above-described tilt angle control and rotation control for each stage, it becomes possible to produce a deposited film with excellent coverage with high productivity.

  As described above, according to the present invention, the deposition property of the deposited film with respect to the side surface and the bottom surface of the recess can be improved regardless of the position on the substrate. Accordingly, the coverage characteristics of the vapor deposition film can be made uniform in the substrate plane.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
FIG. 1 is a schematic configuration diagram of a vacuum vapor deposition apparatus 10 according to a first embodiment of the present invention. The vacuum evaporation apparatus 10 includes a vacuum chamber 11. The vacuum chamber 11 is evacuated to a predetermined degree of vacuum by an unillustrated vacuum pump through an exhaust valve 12.

An evaporation source 13 is installed inside the vacuum chamber 11. The evaporation source 13 is configured by an electron beam evaporation source, but is not limited thereto, and the evaporation source may be configured by a resistance heating source, an induction heating source, a plasma gun, or the like. A metal material such as titanium (Ti) or copper (Cu) is used for the evaporation material (film-forming substance) 14, but other than this, chromium (Cr), nickel (Ni), aluminum (Al), gold Other metal materials such as (Au), silver (Ag), and tungsten (W), and metal oxides such as TiO ₂ and MgO may be used. Note that the evaporation source 13 is not limited to a single one, and a plurality of evaporation sources 13 may be provided.

  A stage 15 is installed inside the vacuum chamber 11 so as to face the evaporation source 13. The stage 15 includes a holding mechanism for holding the substrate W such as an electrostatic chuck or a mechanical clamp, which is simply shown in the drawing. A rotation shaft 15a is provided at the center of the stage 15, and the rotation shaft 15a can be rotated around the axial direction as indicated by an arrow A by a rotation mechanism 18 installed outside the chamber. Thereby, the stage 15 is configured to be rotatable within the surface of the stage surface.

  Further, the stage 15 is configured to be tiltable in a direction indicated by an arrow B by an angle adjusting mechanism 19 installed outside the chamber. Although the tilt center of the stage 15 in the illustrated example is the center of the stage surface, the tilt center is not limited to this, and if the tilt angle of the stage 15 with respect to the evaporation source 13 can be adjusted within a predetermined angle range, the tilt center is There is no particular limitation. The angle adjusting mechanism 19 is preferably a mechanism that can continuously change the tilt angle of the stage 15.

  The rotation mechanism 18 and the angle adjustment mechanism 19 correspond to the “rotation unit” and the “angle adjustment unit” of the present invention, respectively, and are configured as one mechanism unit of a control unit that controls the operation of the stage 15. As will be described later, the control unit performs rotational speed control and tilt angle control of the stage 15 during vapor deposition.

  Specific examples of the configuration of the rotation mechanism 18 and the angle adjustment mechanism 19 are shown in FIGS. As shown in FIG. 2, a second miter gear 32 that meshes with the first miter gear 31 attached to the drive shaft 34 of the drive motor 33 is attached to the tip of the rotating shaft 15 a of the stage 15. Thereby, as shown in FIG. 3, the rotational driving force of the drive motor 33 is converted into the rotational driving force of the rotary shaft 15 a and transmitted to the stage 15.

  On the other hand, as shown in FIG. 2, the rotating shaft 15 a of the stage 15 passes through a peripheral wall of a cylindrical guide shaft 37 that accommodates the drive shaft 34. The guide shaft 37 is rotatably supported by a pair of bearing members 35 and 36 that also serve as a vacuum seal installed on the inner surface of the side wall of the vacuum chamber 11. A gear member 38 is integrally fixed to one end of the guide shaft 37, and the angle of the stage 15 is adjusted via the guide shaft 37 by the rotation of the gear member 38. In the illustrated example, the gear member 38 meshes with a rack 39, and the gear member 38 is rotatable in both forward and reverse directions by the reciprocating movement of the rack 39 in the direction perpendicular to the plane of FIG.

  Next, as the substrate W, a circular semiconductor wafer (such as a silicon wafer) having a concave portion such as a via or a trench formed on the surface, a rectangular glass substrate, or the like is used. The substrate W is held on the stage surface of the stage 15 with its surface side facing the evaporation source 13 side.

  A shutter 16 is installed between the evaporation source 13 and the stage 15. The shutter 16 takes a position for shielding between the evaporation source 13 and the stage 15 and a position for opening between the evaporation source 13 and the stage 15 by a shutter opening / closing mechanism (not shown).

  The vacuum deposition apparatus 10 of this embodiment is further provided with a gas introduction line 17 including a mass flow controller (MFC) that controls the flow rate of the inert gas introduced into the vacuum chamber 11. The inert gas introduced into the vacuum chamber 11 has a function of scattering evaporated particles of the evaporation material 14 from the evaporation source 13 toward the substrate W, and is attached to the side surface and bottom surface of the via formed on the surface of the substrate W. Improves turning ability. In this embodiment, argon (Ar) is used as the inert gas, but other inert gases such as helium (He) and xenon (Xe) may be used.

  The vacuum evaporation apparatus 10 of this embodiment is comprised as mentioned above. Next, this operation will be described. In the present embodiment, a case where a seed layer for electroplating is formed on the surface of the substrate W by the evaporated particles of the evaporation material 14 will be described as an example.

The vacuum chamber 11 is evacuated to a predetermined degree of vacuum (for example, 5.5 × 10 ⁻⁴ Pa or less). The stage 15 holds the substrate W. The evaporation material 14 is heated, dissolved, or sublimated by the evaporation source 13. Next, the shutter 16 is opened, and vapor deposition processing is performed on the surface of the substrate W by scattering the evaporation particles of the evaporation material 14 from the evaporation source 13 toward the surface of the substrate W.

  During vapor deposition, the stage 15 is rotated in-plane by the rotation mechanism 18 and tilted by the angle adjustment mechanism 19. The tilting operation of the stage 15 is continuously performed within the range of the angle θ. Note that the stage 15 may be configured to reciprocate within the range of the angle θ.

  As described above, the inclination angle of the substrate W is changed to the evaporation source 13 so that the incident angle θ of the evaporated particles with respect to the surface of the substrate W (the angle formed between the normal direction of the substrate and the incident direction of the evaporated particles) continuously changes. Will vary. By performing the vapor deposition process in this state, the incident angle dependence characteristics of the evaporated particles due to the geometrical positional relationship between the substrate W and the evaporation source 13 are alleviated. As a result, the evaporated particles with respect to the entire region of the substrate surface. The incident angle distribution can be made uniform.

  As a result, regardless of the radial position of the substrate, it is possible to improve the adhesion of the deposited film to the side surface and the bottom surface of the via. As a result, the coverage characteristics can be made uniform in the substrate plane.

  The inclination angle, inclination movement speed, rotation speed, etc. of the substrate W with respect to the evaporation source 13 are appropriately set according to the aspect ratio of vias formed on the substrate surface, the size of the substrate, the incident angle distribution of evaporation particles, and the like. . That is, the substrate tilt angle control or rotation control is performed under the condition that a desired coverage ratio is obtained for each of all vias on the substrate.

  For example, when a deposited film is formed on the side or bottom of a via having an aspect ratio of 2, the incident angle of evaporated particles to the via is 30 ° or less in consideration of the solid angle from the vicinity of the center of the hole bottom to the hole opening. It is necessary to keep it down. In this case, by setting the conditions that allow the evaporated particles to enter at an incident angle of 30 ° or less with respect to all the vias on the substrate, it is possible to improve the adhesion of the deposited film regardless of the via formation position. It becomes.

  Further, by introducing a predetermined amount of inert gas (argon gas) through the gas introduction line 17 into the vacuum chamber 11 under reduced pressure, the scattering effect of the evaporated particles between the gas molecules is utilized, and the via It is possible to further improve the throwing power with respect to the side surface and the bottom surface.

  Next, the result of an experiment conducted by the present inventor will be described. First, a seed layer (Ti / Cu film) was formed by sputtering on an 8-inch (20 cm) wafer having a via hole with an aspect ratio of 2 formed on the surface. The stage that supports the substrate is fixed with respect to the sputtering target (diameter 8 inches (20 cm)), and the incident angle of the sputtered particles with respect to the substrate is unchanged. Table 1 shows seed layer preparation conditions and film thickness measurement results.

  As shown in Table 1, the film thickness of the vapor deposition film formed on the substrate surface was 5795 nm, whereas the film thickness of the vapor deposition film formed on the side surface of the via was 155 nm, formed on the bottom surface of the via. The film thickness of the deposited film was 136 nm. Therefore, the thicknesses (attachment ratios) of the deposited films on the side and bottom surfaces of the via relative to the deposited film thickness on the substrate surface were 2.7% and 2.3%, respectively.

  Next, a seed layer (Ti / Cu film) was formed using the vacuum vapor deposition apparatus 10 of this embodiment shown in FIG. The substrate used is an 8 inch (20 cm) wafer with vias having a via hole diameter of 60 μm and an aspect ratio of 2. The number of rotations of the substrate (stage) was 10 rotations / minute, and the film was formed by continuously changing the incident angle θ of the evaporated particles from 0 ° to 30 °. The inclination moving speed of the substrate (stage) was set to a speed at which 5 to 10 reciprocations can be made in an angle range of 0 to 30 degrees per minute. Table 2 shows seed layer preparation conditions and film thickness measurement results.

  As shown in Table 2, the film thickness of the vapor deposition film formed on the substrate surface was 4515 nm, whereas the film thickness of the vapor deposition film formed on the side surface of the via was 328 nm (minimum value) to 455 nm (maximum). Value), the film thickness of the deposited film formed on the bottom surface of the via was 796 nm. Therefore, the contact ratios of the side surface and the bottom surface of the via with respect to the substrate surface were 7.3 to 10.1% and 17.6%, respectively. Therefore, when a 0.1 μm seed layer is formed on the side surface of the via, it is only necessary to form a 0.99 to 1.4 μm metal layer on the substrate surface. It was confirmed that a film thickness of a fraction was sufficient.

Subsequently, using the vacuum vapor deposition apparatus 10 shown in FIG. 1, an argon gas was introduced so that the pressure during vapor deposition was 7.5 × 10 ⁻² Pa to form a seed layer (Ti / Cu film). The substrate used is an 8 inch (20 cm) wafer with vias with an aspect ratio of 2. The substrate (stage) was rotated at a rate of 10 revolutions / minute, and the incident angle θ of the evaporated particles was continuously changed from 0 ° to 30 ° for film formation. The inclination movement speed of the substrate (stage) was set to a speed at which 5 to 10 reciprocations can be made in an angle range of 0 to 30 degrees per minute. Table 2 shows seed layer preparation conditions and film thickness measurement results.

  As shown in Table 3, the film thickness of the vapor deposition film formed on the substrate surface was 4620 nm, whereas the film thickness of the vapor deposition film formed on the side surface of the via was 489 nm (minimum value) to 679 nm (maximum). Value), the film thickness of the deposited film formed on the bottom surface of the via was 670 nm. Therefore, the contact ratios of the side surface and the bottom surface of the via with respect to the substrate surface were 10.5 to 14.7% and 13.2%, respectively. Therefore, when a 0.1 μm seed layer is formed on the side surface of the via, it is only necessary to form a 0.7 to 0.95 μm metal layer on the substrate surface. It was confirmed that a film thickness of a fraction was sufficient.

It has been confirmed that the atmospheric pressure of argon gas is effective at 2.0 × 10 ⁻² Pa or more. However, it was also found that when the atmospheric pressure of argon gas exceeds 8.0 × 10 ⁻² Pa, abnormal discharge is likely to occur in the electron beam evaporation source, and stable film formation cannot be performed. Therefore, the atmospheric pressure of argon gas is preferably 2.0 × 10 ⁻² Pa or more and 8.0 × 10 ⁻² Pa or less.

<Second Embodiment>
FIG. 4 shows a vacuum deposition apparatus 20 according to the second embodiment of the present invention. In the figure, portions corresponding to those of the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  The vacuum deposition apparatus 20 of the present embodiment is different from the configuration of the first embodiment described above in that a plurality of (two in the illustrated example) stages 15 are installed inside the vacuum chamber 11. Each stage 15 is installed on the planetary 21 so as to be rotatable and tiltable. The planetary 21 is configured to be rotatable as indicated by an arrow C around a rotation shaft 21a positioned at the center thereof.

  In such a satellite-structured vacuum deposition apparatus 20, the substrate W held on each stage 15 is rotated (rotated) in-plane while revolving around the rotation shaft 21a, and evaporated particles with respect to the surface of the substrate W. The evaporation particles are deposited on the surface of the substrate W while changing the inclination angle of the substrate W with respect to the evaporation source 13 so that the incident angle of the substrate changes continuously.

  Thereby, like the above-mentioned 1st Embodiment, irrespective of the radial position of a board | substrate, the attachment property of the vapor deposition film with respect to the side surface and bottom face of a via can be improved. Accordingly, the coverage characteristics of the vapor deposition film can be made uniform in the substrate plane.

  As mentioned above, although each embodiment of this invention was described, of course, this invention is not limited to this, A various deformation | transformation is possible based on the technical idea of this invention.

  For example, in the above embodiment, the example in which the seed layer forming metal is deposited on the substrate surface has been described, but the present invention may be applied to the formation of a wiring layer or an electrode layer.

  It is also possible to apply a predetermined bias action by applying RF (high frequency power) or DC (direct current power) to the substrate. In this case, it is possible to improve the denseness of the deposited film to be formed. .

It is a schematic block diagram of the vacuum evaporation system by the 1st Embodiment of this invention. It is a schematic block diagram of the rotation mechanism and angle adjustment mechanism of the vacuum evaporation system shown in FIG. It is a schematic block diagram of the rotation mechanism and angle adjustment mechanism of the vacuum evaporation system shown in FIG. It is a schematic block diagram of the vacuum evaporation system by the 2nd Embodiment of this invention. It is a schematic block diagram of the conventional vacuum evaporation system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,20 Vacuum evaporation apparatus 11 Vacuum chamber 13 Evaporation source 14 Evaporation material 15 Stage 17 Gas introduction line 18 Rotation mechanism 19 Angle control mechanism 21 Planetary W Substrate

Claims (6)

In a vacuum chamber, a vacuum evaporation method for depositing evaporated particles from an evaporation source on a surface of a substrate on which a recess such as a via or a trench is formed,
While rotating the substrate in the plane of the surface, and changing the tilt angle of the substrate with respect to the evaporation source so that the incident angle of the evaporation particles to the surface of the substrate is continuously changed, the substrate Depositing the evaporated particles on the surface of the substrate. The vacuum deposition method according to claim 1, wherein the inside of the vacuum chamber is adjusted to an inert gas atmosphere under reduced pressure during the deposition. The vacuum deposition method according to claim 2, wherein the pressure of the inert gas atmosphere is set to 2.0 x 10 ^-2 Pa or more and 8.0 x 10 ^-2 Pa or less. The vacuum evaporation method according to claim 1, wherein a plurality of the substrates are installed in the vacuum chamber, and the evaporated particles are simultaneously deposited on the surfaces of the plurality of substrates. A vacuum chamber;
An evaporation source installed in the vacuum chamber;
A stage disposed opposite the evaporation source;
Rotating means for rotating the stage within the plane of the stage surface;
An angle adjusting means for changing an installation angle of the stage with respect to the evaporation source,
The said angle adjustment means changes the incident angle of the evaporation particle with respect to the surface of the board | substrate on the said stage continuously at the time of vapor deposition. The vacuum vapor deposition apparatus characterized by the above-mentioned. The vacuum deposition apparatus according to claim 5, wherein a plurality of stages are installed in the vacuum chamber.

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