ES2374775A1 - Cathodic spray unit of circular white. (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Spray unit of circular targets. Spray cathodic circular unit that can be used in any high vacuum chamber and that includes: - a head (6) refrigerated white support (24) - a body (18) located behind the head, which contains a coolant circuit with two lines, one inlet and one outlet, for cooling the head (6), with a single cooling bush (1) of liquid and passage of electric current, - an inlet channel (19) of noble gas to the head (6) - an outer casing or anode (21), and - a connecting tube (13) assembled at one end to the outer casing by joining means, and at the other end to a connection box, outside the unit, which contains the connectors of the water, gas and current lines electric (Machine-translation by Google Translate, not legally binding)

Description

White Cathodic Spray Unit Circular

The invention relates to a unit of highly compact cathodic circular spray for obtaining of thin layers of inorganic materials for the study of physical, chemical, mechanical, friction, etc. properties for Its application in machinery and mechanical equipment as coatings of high hardness in tools of cutting and mechanized, in Industries various manufacturers such as the production of coatings decorative or thin layers with optical functionality, in transport and communications such as the production of coatings in microelectronics, magnetic shielding, reflectors on automotive or construction application as to solar control coatings on the glass panel architectural, for example.

Background

The most versatile method used in industry and research since the sixties to produce fine coatings of inorganic materials is sputtering. This is a process that requires high vacuum in the production chamber and is made from a noble gas (argon) plasma created on a pure white of the desired material, which is gradually eroded while spraying into atoms. From the sputtering unit these atoms are emitted and collected on any substrate or object forming a thin layer on it. Commonly, the unit confines the plasma through permanent magnets, and this type is called
"magnetron."

There are different types of units or sources of spray depending on the geometry of the target to be sprayed: circular (disc-shaped white), rectangular and cylindrical. The most used to cover flat objects is the circular one, and the White diameter is typically between 1.5 and 3 inches. Within each geometry, there are specific variants of certain Applications. Another possible classification would be based on the electrical polarization (DC continuous, RF radio frequency, medium MF frequency or Pulsed unipolar and bipolar), although many sources they can be used in various electrical modes just by changing the spray source. Several foreign companies manufacture magnetron type cathode spray sources for targets circular, as well as for large linear targets.

The wide variety of applications and types of sources is reflected in the numerous patents worldwide of the which, referred to circular sources of spray, have as novelty the adaptation to medium frequency and radiofrequency (specific to very dielectric coatings) or various configurations of permanent magnets (for example of interest in magnetic targets), combinations of various magnetron sources or with other type of evaporators, methods to increase the surface Eroded white of high purity, alteration methods plasma (thus optimizing the physical properties of the layers formed), etc., however, each type of source disclosed up to the date requires a custom vacuum chamber, in fact some Patents include the process chamber as an invention.

Description

The present invention relates to a unit or cathode circular spray source that, thanks to its character Compact, it can be used in any high vacuum chamber, can also be used as a source of atomic aggregates and that understands:

-

a refrigerated target support head with a cavity of refrigeration, a metal cathode, a cathode holder and a plurality of magnets,

-

a body located behind the head, which contains a circuit of coolant with two lines, one inlet and one in outlet, for head cooling, with a single gland cooling and electric current,

-

a noble gas inlet channel to the head,

-

a anode or outer shell, grounded, separated from head and a distance over the target typically 1 mm.

-

a O.D. 19 mm assembled at one end to the body by means of connection, and at the other end to an external junction box, outside the vacuum chamber, which contains the connectors of the water, gas and electric power lines and whose interior they cross:

-

he noble gas inlet channel to the head and

-

two coolant inlet and outlet channels that connect by one end to the body's coolant circuit by connection means.

       \ vskip1.000000 \ baselineskip
    

       \ global \ parskip0.900000 \ baselineskip
    

The cathode circular spray source in high vacuum of the invention, has a smaller size than the offered on the market, and pulverize circular white diameters 25 mm (= 1``) and thickness 1-3 mm of almost any desired inorganic material, which is a saving when it comes to High purity material, getting deposit rhythms competitive (1.5 \ {A} / s / 10 W at 8 cm distance with white coppermade). Due to its small size, it can be mounted on flanges small vacuum type DN 40 (70 mm or 2-3 / 4 O.D.) and larger, and enters tubes with an inner diameter greater than 35 mm. This implies that it can be used in the high vacuum equipment of the most research laboratories or production lines, no need for custom cameras, in which it is required to obtain fine coatings on objects that are not large.

It is a very compact source whose novelty resides in that the body integrates:

-

a electric power cable,

-

a water circuit with two lines, one input and one output, Y

-

a noble gas pipeline;

This avoids the need to introduce the gas by another vacuum chamber flange. It is made of materials compatible with ultra-high vacuum, being able to then also use in very clean vacuum processes and the cathode-anode distance is adjustable to operate at different pressures in the range of 10-4 -10-1 mbar.

       \ vskip1.000000 \ baselineskip
    

The compact character of the source is achieved by the following novel features:

-

At water circuit a 3 mm diameter pipe is used per within a 6 mm diameter tube, of a single wall, for have a coolant inlet and outlet channel in Acceptable flows (L / min), thereby avoiding the need for two liquid and electric current passages that would force a greater device diameter

-

The water circuit inlet and outlet tubes to the box external connections by means of a plurality of fittings of compression located in the external junction box and not in the body of the spray source. This is so because two fittings commercials for 6 or 4 mm pipes would take up a lot of space inside of the body and with difficult access.

-

He cathode support is made of ferritic stainless steel, which makes In the magnetic circuit a magnetic clamp is used for magnets This provides sufficient magnetic grip strength and avoid the use of a mechanical fastener that would add parts to the source.

       \ vskip1.000000 \ baselineskip
    

In general, the invention relates to a sputtering unit composed of steel parts stainless, copper and aluminum, which form the head of the unit and are joined together with radial arc welding or alloy welding silver, to ensure high vacuum tightness. I only know they use flat copper joints inside, then it is not necessary no plastic o-ring and therefore the unit holds temperatures of 250 ° C.

The unit operates at low noble gas pressures (10 <2> -10 <3> mbar) introduced after evacuating The high vacuum chamber. To do this you must polarize with a source of power for plasma, in continuous, radiofrequency or pulsed. The Commercial electronics models for magnetron units serve to operate this invention.

Contains inbound and outbound pipeline cooling water in a cavity in the cathode (with pressures usual street circuit flow rates are achieved enough of L / min) and contains noble gas pipeline (argon) to the base of the cathode, which avoids the need for introduce it through the chamber flange, and this is also achieved that the pressure of the gas on the target is greater than in the rest of the camera.

Description of drawings

Then it goes on to describe very brief a series of drawings that help to better understand the invention and that expressly relate to an embodiment of said invention presented as a non-limiting example of is.

Figure 1 is a diagram of the interior of the body and head of the spray source.

References represent the following elements:

one.-

Liquid and current pass-through electric

2.-

Tube of external diameter 3 mm.

3.-

Cable gland tube.

4.-

Distribution bushing

5.-

Cap with holes.

       \ global \ parskip1.000000 \ baselineskip
    

6.-

Head.

7.-

Copper cathode

8.-

Cathode support.

9.-

Cavity.

10.-

Permanent magnets.

eleven.-

White clamping cap.

12.-

Anode Base

13.-

External diameter connection tube 19 mm

14.-

DN 40 vacuum flange or passage outside the camera.

fifteen.-

DN 16CF vacuum flange.

16.-

Insulating.

17.-

Threaded rod

18.-

Spray unit body.

19.-

Gas pipe.

twenty.-

35 mm outer diameter tube.

twenty-one.-

Anode or outer shell of the head.

22.-

Liquid inlet channel.

2. 3.-

Liquid outlet channel.

24.-

White.

25.-

High vacuum chamber wall.

Description of a preferred embodiment of the invention

The source or circular spray unit Cathodic of the invention comprises, as shown in the Figures 1 and 2, of:

a) A body (18) that contains a single gland (1) of liquid and electric current, with an electrical insulator (16), for a pipe (3) of 6.3 mm diameter, of steel and in whose inside is a tube (2) 3 mm long, of coolant inlet into the cavity (9) of the head of the unit, made of steel and bent as shown in figure 2. The 3 mm (2) water inlet pipe is welded with arc to body of a steel bushing (4) containing a cover (5) welded to the bushing (4) with arc and with two 3 mm holes, for the connection of two tubes, one inlet (22) and the other outlet (23) of coolant, also 3 mm, thus configuring the water circuit that will cool the head components (6).

b) A head (6) arc welded to the tube 6.3 mm (3) of the bushings (1), at one of its ends and comprising inside:

-

a copper cathode (7) machined on this material

-

he cathode support (8) in ferritic stainless material welded with silver alloy, and with the mechanized thread in the support.

-

magnets NdFeB permanent (10) that are manually mounted on copper cathode holes and magnetically attached to it by the attraction of the ferritic steel support (an estimated force 0.1 N appropriate to put or remove magnets by hand).

-

a cavity (9) that closes the body's water circuit, to refrigerate the inside of the cathode with a higher flow rate of liter per minute if water from the street circuit is used.

c) An external housing or anode (21) of the unit separated from the head (6) with a minimum distance between them of 1 mm over white (24) but adjustable from 0.5-2.5 mm according to the range of the working pressure, and which make up several Parts, which can be assembled and disassembled with screws:

-

a piece of steel we call "Anode Base" (12) that It includes the gas inlet.

-

threaded rods (17) at one end the base of the anode (12) and on the other to the body (18),

-

a outer diameter tube (O.D.) 35 mm (20) attached at one end to the body (18).

       \ vskip1.000000 \ baselineskip
    

The outer diameter tube 35 mm (20) is then welded to a vacuum closure based on a flange of the standard DN 16 CF (15), and to a 19 mm long connection tube of diameter (13). It is this connecting tube (13) that reaches the outside the vacuum chamber, either through a pipe flange with an o-ring or being welded to a flat seal flange of copper (standard DN 40 or greater) or passage outside the chamber (14).

The outer shell is grounded and separated at least 2-2.5 mm from the inner parts of the cathode Said separation minimizes the electric field between the cathode and anode and thus prevent the formation of plasma or arcs not desired This separation is reduced to 1 mm in the area adjacent to the white, so that here the electric field is intense when the Cathode polarizes to hundreds of volts or kilovolts. If the gas flows, the intense electric field causes the ignition of a plasma that is created and automatically confined on the target by effect of the magnetic field of permanent magnets (10).

The unit closes in a high vacuum chamber (25) that works on the low argon pressure introduced by a pipe (19) to the spray head, according to figure 2, and Connects to a junction box that includes union fittings to:

-

the flexible water inlet and outlet pipes,

-

the gas dosing valve, and

-

the electrical connection that takes advantage of the central tube to polarize the cathode.

       \ vskip1.000000 \ baselineskip
    

Like water pipes and the entire inner part it will polarize at high voltage, it is necessary to maintain the insulation Electrical of the tubes by means of several Teflon separators inside of the 19 mm tube (13), of the spray source body (18) and junction box.

The operation of the unit in a case particular is the following:

- On the copper cathode (7) with the magnets (10) instead, the user places the target or disc to be sprayed (24) of high purity matter and diameter 25.5 ± 0.5 mm, and what mechanically fastened with a stainless steel bushing (11) (AISI 316/304) and diameter 28 mm, which threads inside the support (8). This entails sufficient physical contact between the target and the copper cathode so that the heat generated in the spray can drain A minimum distance of 2 mm to the anode is respected to avoid electric shocks that do not take place on, the White.

- From the outer side of the wall of the vacuum chamber (25) a leak valve or a control valve mass flow dose a noble gas flow, typically lower 100 sccm, raising the pressure inside the chamber to the range 10-2 -10-3 mbar. This atmosphere of argon u another noble gas is significantly larger in the exit zone over the copper cathode (7), and suitable for lighting a confined plasma over white (24).

- The distribution of magnets (10) of the head create a magnetic field of axial symmetry and, therefore, the Argon plasma is confined in a ring over the target (24), then producing its gradual spraying.

- The power cable of a Commercial power source connects to the junction box and take advantage of the 3 mm (2) pipe in contact with the inside of the pasamuros (1), to polarize the cathode. In this way, there are no tubes plastic inside the head of the unit that may deteriorate with heat in a UHV camera or for prolonged use.

- The water or coolant circuit is based on a single pass of liquid and electric current, which facilitates that the total diameter of the design does not exceed 35 mm. How can be seen in the scheme, the entrance of water to the cathode is through of a 3 mm pipe and the outlet through the gap between it and the tube 6.3 mm Since the step section at the exit is somewhat larger, the Refrigerated cavity in the cathode is kept full of liquid.

Claims (17)

1. Cathodic circular white spray unit characterized by comprising:

-

a head (6) refrigerated target support (24) comprising a cooling cavity (9), a metal cathode (7), a support cathode (8) and a plurality of magnets (10),

-

a body (18) connected to the head, which contains inside a coolant circuit with two lines, one inlet and another output, for cooling the head (6), with a single liquid cooling and flow passage (1) electric,

-

a Inlet channel (19) of noble gas to the head (6)

-

a outer shell or an anode (21), grounded, separated from the head (6) with a minimum distance between them of 1 mm over the white (24) but adjustable from 0.5-2.5 mm according to the working pressure range,

-

a connecting tube (13) assembled at one end to the housing outside by joining means, and at the other end to a box of connections, outside the unit, which contains the connectors of the water, gas and electric current lines and through whose interior they cross:

-

he noble gas inlet channel (19) to the head and

-

the coolant inlet and outlet channels (22 and 23) that are connect at one end to the coolant circuit of the body (18) by connection means.

         \ vskip1.000000 \ baselineskip
      

2. A cathodic circular spray unit according to claim 1 characterized in that the total diameter of the unit is less than or equal to 35 mm. 3. Cathodic circular spray unit according to previous claims characterized in that the unit is closed in a high vacuum chamber (25). 4. A sputtering unit for circular targets according to claim 3, characterized in that the pressure inside the chamber rises to the range 10 -2 -10-3 mbar. 5. A sputtering unit for circular targets according to previous claims, characterized in that the coolant circuit of the body (18) comprises a 6 mm diameter pipe (3), inside which there is a 3 mm tube of liquid inlet refrigerant (2) to the cavity (9) of the unit head. 6. A sputtering unit for circular targets according to previous claims, characterized in that the means for connecting the inlet (22) and outlet (23) channels of coolant to the coolant circuit of the body (18) comprise a steel bushing. (4) containing a cover (5) welded to the bushing (4) with an arc and with two holes, for the connection of two flexible pipes, one inlet (22) and the other outlet (23) of coolant. 7. A cathodic circular spray unit according to claim 6, characterized in that both the inlet and outlet coolant channels (22, 23) and the holes in the lid (5) have a diameter of 3 mm. 8. A cathodic circular spray unit according to previous claims, characterized in that the permanent magnets (10) of the head (6) are NdFeB. 9. A sputtering unit for circular targets according to previous claims, characterized in that the cathode support (8) of the head is made of ferritic steel. 10. A cathodic circular spray unit according to previous claims, characterized in that the external housing of the head or anode (21) comprises a base of the anode (12) attached to threaded rods (17) joined at the other end to the body (18) , and this in turn to a tube of outer diameter 35 mm (20). 11. A cathodic circular spray unit according to previous claims, characterized in that the connection means of the connecting tube (13) to the outer housing comprise a flange of the standard DN 16 CF (15). 12. A cathodic circular spray unit according to claims 2-11 characterized in that the connecting tube (13) reaches the outside of the vacuum chamber, either through a tube flange with an O-ring or being welded to a flange of flat copper joint standard DN 40 or greater (14). 13. A sputtering unit for circular targets according to the preceding claims, characterized in that the electrical insulation of the tubes is maintained in the connection tube (13), the body (18) and the connection box by means of several Teflon separators. 14. A cathodic circular spray unit according to previous claims, characterized in that the target or disk to be sprayed (24) is 25.5 ± 0.5 mm in diameter. 15. A sputtering unit for circular targets according to previous claims, characterized in that the blank (24) is mechanically held by a stainless steel bushing (11) (AISI 316/304) and diameter 28 mm, which threads inside the support (8) ). 16. A cathodic circular spray unit according to previous claims, characterized in that a leak valve or a mass flow control valve doses a noble gas flow from the outside of the vacuum chamber (25). 17. A cathodic circular spray unit according to previous claims, characterized in that the pieces that form the head (6) of the unit are joined together with radial arc or silver alloy welding.