JP2017088973A - Plasma sputtering equipment - Google Patents

Abstract

In plasma sputtering, plasma generation efficiency and smooth movement of a sputtering material are made possible. A target material holding unit for holding a target material and a plasma generation unit having a plasma generation surface, the plasma generation unit generating plasma on the side of the surface of the target material held by the target material holding unit. The surface is positioned and the plasma generation surface faces the target material surface side so as to form an obtuse angle with the target material surface, and the plasma generation surface is perpendicular to the target generation surface in the vertical direction +20 degrees to the vertical direction +45. It is preferable to have an angle of degrees, which improves the sputtering efficiency, facilitates the movement of the sputtered material, and improves the deposition efficiency when depositing the sputtered material on the deposition target material. The thermal damage to the material to be deposited during sputtering is minimized, and a low temperature process is realized. [Selection] Figure 1

Description

  The present invention relates to a plasma sputtering apparatus that generates plasma and sputters a target material, and preferably deposits a material layer by sputtering deposition in the manufacture of semiconductors and display (hereinafter referred to as semiconductor) devices. The present invention relates to a technical field applicable to a plasma generation apparatus.

  A sputter deposition process is a process used in the manufacture of various semiconductor devices. In a typical sputter deposition process, plasma is generated in the vicinity of a sputter target material by a plasma generator that generates an electric field in order to deposit a material on a semiconductor substrate. A negative bias can be applied to the sputter target material. Electrons generated inside the plasma move in the vicinity of the target material and generate ions in the plasma that strike the surface of the target material and expel the material from the target material (ie, “sputter”). The sputtered particles move to the surface of the semiconductor substrate and deposit there. Further, in magnetron sputtering using a magnetic field, the plasma is under the influence of a magnetron magnetic field generated by a magnet, and the plasma can travel around the magnetron magnetic field along a spiral path and strike the surface of the target material efficiently. A widely used industrial sputtering system is a parallel plate type magnetron sputter in which a substrate and a target are arranged in parallel. However, the damage caused by direct exposure of the substrate to the plasma is a problem. Patent Document 1 proposes a “counter-on-target method” in which plasma is generated between targets and only sputtered particles fly to the substrate therefrom.

JP-A-10-330936

  By the way, when the sputtered particles proceed from the target material to the substrate to be deposited, there is a tendency that the sputtered particles travel along a straight path having an angle of incidence with respect to the substrate surface. On the other hand, there is a problem that regions of high-density plasma overlap on the flight path. As a result, molecules ionized by the plasma (eg, Ar) and sputtered particles knocked out of the target material cross (mix) between the target material and the substrate. In particular, sputtering with high-density plasma usually requires that the chamber be operated at a relatively high pressure, resulting in a high frequency of collisions between the plasma ions and the material atoms of the sputter material, and the scattering of deposited atoms. Increases as well. Due to the scattering of the deposited atoms, the sputtering efficiency is deteriorated.

Further, the thickness of the deposited layer on the substrate becomes thicker at the portion of the substrate that is aligned with the center of the target, and becomes thinner at the outer region (which causes film non-uniformity and deterioration of step coverage). In addition, if the input power to the plasma is increased to increase the deposition rate, a large number of hot electrons are generated from the above structure and reach the substrate along with the deposited atoms, causing the substrate to become hot and causing thermal damage. Will give.
In addition, the problem with parallel plates and counter electrodes is that “the deposition atom has a high-density plasma cloud in the path from the target to the substrate and penetrates it to reach the substrate. The problem is that the substrate temperature rises due to the influence of the thermal electrons, “molecules other than the sputtering material remain in the film (the film quality deteriorates)” and “orbit of the sputtered particles changes due to the power applied to the plasma”. is there.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a plasma sputtering apparatus capable of performing an effective plasma sputtering process by smoothly moving the sputtering particles and the plasma particles.

That is, in the plasma sputtering apparatus of the present invention, the first aspect of the present invention is a target material holding portion for holding a target material,
A plasma generation unit having a plasma generation surface,
The plasma generation unit is located at a side of a target material surface held by the target material holding unit, and the plasma generation surface faces the target material surface side and is obtuse with the target material surface. It is installed to make.

  In another form of the plasma sputtering apparatus according to the present invention, the plasma generation surface has an angle of vertical direction +20 degrees to vertical direction +45 degrees with respect to the target material surface. .

  In another aspect of the present invention, the plasma sputtering apparatus of the present invention has a deposition material holding unit that positions the deposition material at a position facing the target material surface held by the target holding unit. It is characterized by.

  According to another aspect of the present invention, there is provided a plasma sputtering apparatus according to the aspect of the invention, wherein the plasma generation unit includes a plurality of the plasma generation surfaces.

  The plasma sputtering apparatus of another form is characterized in that, in the present invention of the form described above, the plurality of plasma generation surfaces have at least two facing surfaces.

  According to another aspect of the present invention, there is provided the plasma sputtering apparatus according to the aspect of the invention, in which the plasma generation unit is disposed in a space surrounded by the plasma generation surface in a space between the target material surface and the plasma generation surface. It has the plasma gas inlet which introduce | transduces.

  In another aspect of the present invention, the plasma sputtering apparatus includes a high-frequency antenna along the plasma generation surface.

  In another aspect of the present invention, the plasma sputtering apparatus includes a bias power supply that applies a bias voltage to the target holding unit.

  In another form of the plasma sputtering apparatus according to the present invention, the plasma generation unit has a magnetic field generation unit that generates a magnetic field inside the plasma generation surface.

  According to the present invention, the sputtering efficiency is improved and the movement of the sputtered material becomes smooth. When depositing the sputter material on the material to be deposited, the efficiency of the deposition is improved, and thermal damage to the material to be deposited during sputtering is minimized, contributing to the realization of a low temperature process.

It is front sectional drawing which shows the state holding the target material with the plasma sputtering device of one Embodiment of this invention. Similarly, it is a cross-sectional perspective view. Similarly, it is an enlarged perspective view showing a plasma generation unit in which a protective plate is omitted. In one Embodiment of this invention, it is a figure explaining the inclination angle of the target material surface and a plasma production surface. It is a schematic diagram at the time of operation | movement in the plasma sputtering apparatus of one Embodiment of this invention. It is front sectional drawing which shows the state which hold | maintained the target material with the plasma sputtering apparatus of other embodiment of this invention. It is a disassembled perspective view which shows the plasma production | generation part in the plasma sputtering device of further another embodiment of this invention.

Below, plasma sputtering device 1 of one embodiment of the present invention is explained based on an accompanying drawing.
As shown in FIGS. 1 and 2, the plasma sputtering apparatus 1 includes a sealed processing chamber 2, and the inside of the processing chamber 2 can be evacuated by a vacuum device (not shown).
The processing chamber 2 has a top plate portion 2b and a bottom plate portion 2c, and has inclined walls 2a and 2a on both sides which are inclined with respect to the bottom plate portion by making the width of the bottom plate portion 2c smaller than the top plate portion 2b. The top plate portion 2b and the bottom plate portion 2c extend in the length direction (the illustrated depth direction) with the same width (the illustrated left and right direction). That is, in this embodiment, a chamber having a substantially V-shaped cross section is provided.
In addition, the installation position and installation angle of the processing chamber 2 are not particularly limited.

A target material holding unit 3 is provided on the bottom plate 2c of the processing chamber 2, and the target material 100 is installed on the upper surface thereof. A bias power supply 10 for applying a back bias voltage is electrically connected to the target material holding unit 3.
A substrate holding part 4 is provided on the lower surface side of the top plate part 2b of the processing chamber 2, and the substrate 110 can be held with the lower surface exposed to the substrate holding part 4 as shown in FIG. The substrate 110 corresponds to a material to be deposited. Note that the target material holding unit 3 and the substrate holding unit 4 are in a positional relationship in which the surface of the substrate 110 faces the surface of the target material 100 installed in the target material holding unit 3.

Both of the inclined walls 2 a and 2 a are provided with a plasma generation unit 5, and the inner surface thereof is a planar plasma generation surface 5 a facing the space in the processing chamber 2. Therefore, in this example, the plasma generation surfaces 5a and 5a on both sides are at positions facing each other.
That is, in this embodiment, the plasma generation unit 5 is positioned in the plasma chamber with a substantially V-shaped cross section. Further, in this embodiment, the target material is disposed on the bottom surface, but the number of target materials and plasma generation units and their mounting positions on the three surfaces are free depending on the application.

In this embodiment, the inclined walls 2a, 2a have an obtuse angle with the surface of the target material 100 installed on the target material holding unit 3, and the plasma generating unit 5 provided on the inclined wall 2a As shown in FIG. 4, the plasma generation surface 5a has the same inclination angle θ as that of the inclined wall 2a. That is, the plasma generation surface 5a and the surface of the target material 100 form an obtuse angle θ.
In the present invention, the inclination angle θ may be an obtuse angle, and is not limited to a specific angle. However, the inclination angle is preferably in the range of vertical direction +20 degrees to vertical direction +45 degrees, A range of +32 degrees ± 10 degrees in the direction is more desirable.

  The flight path of the sputtered particles and the high-density plasma region can be separated by the inclination of the plasma generation surface. In particular, by setting the tilt angle of the plasma generation surface within the above range, the region having the highest plasma density can be kept away from the flight path of the sputtered particles. When the tilt angle of the plasma generation surface is smaller than the vertical direction +20 degrees, the separation between the flight path of the sputtered particles and the high-density plasma region is insufficient, and the tilt angle is larger than the vertical direction +45 degrees. In this case, there is no problem in separating the flight path of the sputtered particles from the high-density plasma region, but it is not preferable because the efficiency of inducing plasma ions generated in the plasma region to the target surface by an electric field decreases.

As shown in FIG. 5, the plasma generation unit 5 includes a high frequency power source 11 that generates a high frequency electric field on the plasma generation surface 5a, and high frequency power is supplied at a predetermined frequency.
In addition, a plasma gas introduction part 6 is provided along the longitudinal direction at the center part in the height direction of the plasma generation surface 5 a, and plasma gas is supplied from the outside of the processing chamber 2. In this embodiment, Ar gas is used as the plasma gas. However, the present invention is not limited to a specific type of plasma gas.
This embodiment has a magnetron-free (no magnetron) structure. However, the present invention may have a structure having a magnetron.

  Further, in the inclined wall 2 a, as shown in FIG. 5, a reaction gas introduction unit 7 is formed above the plasma generation unit 5, and a reaction gas is supplied from the outside of the processing chamber 2. 1 and 2, the reaction gas introduction unit 7 is not shown. In this embodiment, oxygen is supplied as a reaction gas. In the present invention, the type of reaction gas is not limited to a specific type, and a plurality of types of reaction gas may be used. In the present invention, a reaction gas may not be used.

  In the above description, the target material holding unit 3 is described as having the bottom plate 2c of the processing chamber 2 and the substrate holding unit 4 being provided on the top plate 2b of the processing chamber 2. The relationship is not particularly limited. In this embodiment, the substrate holding unit 4 is described as being included in the processing chamber 2. However, the substrate holding unit 4 may exist outside the processing chamber 2. The position of is not particularly limited.

Next, details of the plasma generator 5 will be described with reference to FIG.
In the plasma generation unit 5, two metal plates 50 and 51 are arranged in the longitudinal direction with their edges facing each other with an interval in the vertical direction. A long recess 6a is formed between the two metal plates 50 and 51, and a plurality of slits 6b arranged in the longitudinal direction at intervals in the recess 6a are provided. Are connected to form a plasma gas inlet 6. The plasma gas is introduced into the chamber of the processing chamber 2 through the slit 6b.

The upper surfaces of the metal plates 50 and 51 are covered with a ceramic protection plate 52 except for the periphery of the recess 6a, and the metal plates 50 and 51 are protected from being damaged by plasma.
Conductive wires 50a and 51a are joined to the edges of both ends of the metal plates 50 and 51 along the longitudinal direction, and a power feeding portion of the high frequency power supply 11 is connected to both ends of the conductive wires 50a and 51a, respectively. Yes. Thus, a high frequency electric field can be generated in the gap between the metal plates 50 and 51 by flowing a high frequency current through the conductive lines 50a and 51a, respectively.

Next, the operation of the plasma sputtering apparatus of the above embodiment will be described with reference to the schematic diagram of FIG.
A target material 100 of a desired material is held on the target material holding unit 3, and a desired substrate 110 is installed on the substrate holding unit 4. In the present invention, the type of the target material and the type of the substrate are not particularly limited.
Thereafter, the inside of the processing chamber 2 is evacuated by a vacuum device (not shown), Ar gas is introduced into the processing chamber 2 from the plasma gas introduction unit 6, and O 2 gas is introduced into the processing chamber 2 from the reaction gas introduction unit 7. Further, the high frequency power supply 11 supplies current to the conductive wires 50 a and 51 a to generate a high frequency electric field in the gap between the metal plates 50 and 51, and the bias power supply 10 applies a back bias to the target material holding unit 3.

The plasma gas blown out from the plasma gas introduction unit 6 is turned into plasma by a high frequency electric field. At this time, the plasma gas is introduced from the recess 6a of the plasma gas introduction part 6 through the slit 6b, so that a sufficient contact time between the gas and the electric field is obtained, and the gas is improved into plasma.
On the other hand, in the target material holding unit 3, a bias voltage is applied, and the plasma generated above is attracted to the target material 100 side and the target material 100 is hit with the plasma. At this time, since the plasma generation surface 5a has an obtuse angle with respect to the surface of the target material 100, the plasma flow is less likely to fly far away and is biased toward the center of the surface of the target material 100. In other words, the high-density plasma region is limited to the vicinity of the plasma generation unit 5, and the flow of plasma to the outside slightly increases from the center side of the surface of the target material 100.

In the target material 100, the sputtered particles 100a fly out toward the substrate 110 by being hit with plasma. At this time, the flow of the plasma particles is reduced at the center of the surface of the target material 100, the crossing state between the sputtered particles 100a and the plasma particles is reduced, and the flow of the sputtered particles 100a jumping out of the target material 100 is not impaired. .
Therefore, it is preferable that the flight path of the sputtered particles and the high-density plasma region can be separated.
In the above-described embodiment, by arranging the plasma generation unit and the target material in a V shape, the ionization of Ar molecules by plasma and the generation region of sputtered particles are separated, thereby “ionization of Ar molecules by plasma ions” and “ The efficiency of “film formation with sputtered particles” can be increased. Moreover, the phenomenon that the substrate temperature rises due to the influence of the thermal electrons attached to the sputtered particles can be suppressed.

  In addition, even for a plasma source using a general magnetron, which has a wider high-density plasma region than an apparatus that does not use a magnetron, the plasma density can be increased by arranging the tilt angle of the target generation surface within the above range. Can be kept away from the flight path of the sputtered particles.

In addition, although the said embodiment demonstrated what has two plasma production surfaces to face, as this invention, the number of plasma production surfaces is not limited to a specific number.
FIG. 6 shows a plasma sputtering apparatus 1a in which the plasma generator 5 is provided only on one of the inclined walls 2a. Also in this embodiment, ionization of plasma gas by plasma and the generation region of sputtered particles can be separated, and the efficiency of film formation by plasma and sputtered particles can be increased.

In the above-described embodiment, the plate-shaped antennas are arranged in pairs and the high-frequency electric field is formed between the plate-shaped antennas. However, any shape can be used as long as a plasma generation surface can be obtained. There is no particular limitation on the arrangement.
FIG. 7 shows the antenna 16 arranged in a meandering manner in the plasma generator 15. By connecting high-frequency power supply units to both ends of the antenna 16, a high-frequency electric field can be formed around the antenna 16. A protective plate 17 such as ceramic is provided on the inner surface side of the antenna 16. In this embodiment, a planar plasma generation surface 15 a is formed inside the protective plate 17. As described above, the plasma generation surface 15a is installed so that the plasma generation surface 15a forms an obtuse angle with respect to the surface of the target material, so that the same effect as in the above embodiment can be obtained.

Next, examples of the present invention will be described.
The plasma sputtering apparatus (see FIG. 1) of the present invention described in the above embodiment was used. In addition, a DC power source was added to the same apparatus on the back side of the substrate and the target, respectively, and a parallel plate type magnetron sputtering configuration was simulated as a comparative example. The experimental chamber capacity was 30 cm ³ , and the high frequency power for plasma generation was 300 w input in both the examples and the comparative examples.
As a result of the operation of the plasma sputtering apparatus, a thermolabel was applied on the substrate, and in the examples, the results were 50 ° C. or lower for 1 hour discharge and 100 ° C. or lower for 6 hour discharge.
On the other hand, in the comparative example, the substrate exceeded 100 ° C. within 5 minutes from the start of discharge.

  Although the present invention has been described based on the above-described embodiments and examples, it goes without saying that modifications in various features of the present invention are obvious to those skilled in the art, or are routine mechanical or electrical. It should be understood that some may become obvious after other considerations that are specific design issues. Other specific examples are also possible, the specific design of which depends on the application. Thus, the scope of the present invention is not limited to the specific embodiments described herein, but should be limited only by the appended claims and equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Plasma sputtering apparatus 1a Plasma sputtering apparatus 2 Processing chamber 2a Inclined wall 3 Target material holding part 4 Substrate holding part 5 Plasma generation part 5a Plasma generation surface 6 Plasma gas introduction part 6a Depression part 6b Slit 7 Reactive gas introduction part 10 Bias power supply 11 High-frequency power supply 15 Plasma generation unit 15a Plasma generation surface 16 Antenna 17 Protection plate 50 Metal plate 51 Metal plate 52 Protection plate 100 Target material 100a Sputtered particle 110 Substrate

Claims (9)

A target material holding part for holding the target material;
A plasma generation unit having a plasma generation surface,
The plasma generation unit is located at a side of a target material surface held by the target material holding unit, and the plasma generation surface faces the target material surface side and is obtuse with the target material surface. A plasma sputtering apparatus, which is installed so as to form   The plasma sputtering apparatus according to claim 1, wherein the plasma generation surface has an angle of vertical direction +20 degrees to vertical direction +45 degrees with respect to the target material surface.   3. The plasma sputtering apparatus according to claim 1, further comprising: a deposition target holding unit that positions a deposition target at a position facing the target material surface held by the target holding unit.   The plasma sputtering apparatus according to claim 1, wherein the plasma generation unit includes a plurality of the plasma generation surfaces.   5. The plasma sputtering apparatus according to claim 1, wherein the plurality of plasma generation surfaces have at least two facing surfaces. 6.   The plasma generation unit has a plasma gas introduction port for introducing a plasma gas into a space between the target material surface and the plasma generation surface at a location surrounded by the plasma generation surface. The plasma sputtering apparatus according to any one of 1 to 5.   The plasma sputtering apparatus according to claim 1, further comprising a high-frequency antenna along the plasma generation surface.   The plasma sputtering apparatus according to claim 1, further comprising a bias power supply that applies a bias voltage to the target holding unit.   The plasma sputtering apparatus according to claim 1, wherein the plasma generation unit includes a magnetic field generation unit that generates a magnetic field inside the plasma generation surface.

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