DE4038577A1 - Coating substrate with silicon di:oxide - in which multicomponent target in evacuated chamber contg. argon@ and oxygen@ is used - Google Patents

Abstract

A process and appts. for coating a substrate (1), e.g. with SiO2, are described in DE4025231, having a current source (10) connected to a cathode (5) enclosing magnets (7,8,9) arranged in an evacuated chamber (15,15a). In this patent of addn. the multicomponent target (35) comprises a cylindrical middle part (35a) made of a material (e.g. Si) with a high affinity to reactive gas and two cylindrical outer parts (35b) connected in the axial direction to the back end of the middle part (35a) and is made of a material (e.g. Sn) with a low affinity to reactive gas. The reaction gas used is e.g. Ar and O2. USE/ADVANTAGE - The layer properties of oxidic or metallic thin layers can be modified.

Description

The invention relates to a method and a device for the reactive coating of a substrate, for example with silicon dioxide (SiO ₂ ), consisting of a current source which is connected to an electrode arranged in an evacuable coating chamber and which is electrically connected to a target, that is atomized and its atomized particles are deposited on the substrate, a process gas being able to be introduced into the coating chamber and that

1. either the target to be atomized is in several parts, with a central one opposite the substrate Part of the target made from a more reactive material is formed as the enclosing this central part  end or framing part, being between the Substrate on the one hand and the multi-part target on the other hand, an aperture is provided with a central opening, which is about the configuration of the has middle target part, and wherein a Reactive gas inlet and a process gas inlet or a common inlet for both gases are provided and the magnetic field of the cathode is designed that during the coating process at the same time or periodically sputtering the more reactive target materials is effected, or that

2. The target to be atomized is in several parts, one radially outer, opposite the substrate the part of the target made of a more reactive material is formed as that of this outer part closed or framed part, with between the substrate on the one hand and the multi-part target on the other hand, an aperture is provided, which is approximately the configuration of the middle target part has, and wherein a reactive gas inlet and a pro zeßgaseinlass or a common inlet for both Gases are provided and the magnetic field of the cathode is designed so that during the coating sputtering the more reactive target material rials in the oxidic and the less reactive Target material is effected in metallic fashion after patent ............... (patent application P 40 25 231.0).

In known methods for coating substrates with the help of cathode sputtering and materials a high affinity for reactive gas there is the problem that in addition to the substrate itself, parts of the device,  like the inner wall of the process chamber or parts of Blen the one with electrically non or poorly conductive mate rialien coated, which is the frequent change of the Process parameters during a single coating pro process or a frequent interruption of the process and also a frequent cleaning or replacement of Requires sharing the device.

The present invention is therefore based on the object based on an apparatus and a method for sputtering of materials with high affinity for a reactive gas to create - as already in the main patent ............. (Patent application P 40 25 231.0) described - that one enables uniform or stable process and a Makes cleaning the parts of the device unnecessary, without conventional or existing devices conditions or systems are unsuitable for this or without these essential or costly conversions or Changes need to be made.

This object is achieved in that e.g. B. the multi-part target from a hollow cylindrical middle part made of a material with high affinity for Reactive gas, for example Si, and from two hollow cylinders outer parts that exist in the axial direction tion on the outside of the front of the middle section connect and which from a material low affi to the reactive gas, for example Sn, exist.

Another solution specifically for manufacturing of layers of high-purity materials instead the use of targets from two different ones Source materials a target from one material, however  with zones of different sputtering power density use, on the one hand

• a) an anode in a zone of higher power density is arranged below and parallel to Axial direction of the tube cathode and their Base area smaller than the projection area of the cylindrical targets is formed with Tar get material is coatable under oxidic fashion, and on the other hand
• b) in a zone of low power density (electrical conductive) an oxide layer made of target material preferably on the substrate to be coated, con is condensable.

Furthermore, the following solution is also conceivable that, for example, a flat target is formed in places from a material which has a lower affinity for oxygen than that of which the target consists, and these locations are arranged around a main sputter trench, wherein an aperture arrangement is designed so that the material has lower affinity for oxygen, for. B. Sn, is mainly precipitated on the aperture in metallic fashion and the rest of the material, for. B. Si, through the aperture on the substrate as an oxide, for. B. SiO _{2 is} applied.

Further details and features are in the patents sayings marked in more detail.

The present invention relates to methods and devices for the modification of layer properties thinner Layers that can be oxidic or metallic.

The invention allows a wide variety of designs opportunities to; some of them are in the attached Drawings shown schematically, the Vorrich show the reactive coating of substrates, in fact:

Fig. 1 a sputtering with a magnetron sputtering cathode in section,

Fig. 2 shows a circular target consisting of two NEN Various metals in perspective view,

Fig. 3 is a magnet arrangement for a pipe cathode in section,

Fig. 4 is a tube cathode according to Fig. 3 in shear perspektivi view,

Fig. 5 is a magnet assembly in section of side ditch,

Fig. 6 shows a cathode with a main and several secondary trenches according to Fig. 5 in plan view and

Fig. 7 shows a sputtering cathode arrangement with shiftable magnets in section.

In Fig. 1, a substrate 1 is shown to be provided with a thin layer 2 of an oxide (eg., Silicon dioxide or aluminum oxide). This substrate 1 is opposite a multi-part target 3 , which is to dust. The target 3 is connected via a plate 4 to an electrode 5 , which rests on a yoke 6 , which includes five magnets 7 , 8 , 9 , 30 , 31 between it and the element 4 .

The polarities of the poles of the five magnets directed at the target 3 alternate, so that the south poles of the two outer magnets 30 , 31 with the north poles of the inner magnets 7 , 9 cause approximately circular arc-shaped magnetic fields through the target 3 .

These magnetic fields compress the plasma in front of the target 3 , so that they have their greatest density where the magnetic fields have the maximum of their arcs. The ions in the plasma are accelerated by an electric field that builds up on the basis of a DC voltage that is indicated by a DC power source 10 . This direct current source 10 is connected with its negative pole to the electrode 5 . The electric field is perpendicular to the surface of the target 3 and accelerates the positive ions of the plasma towards this target 3 . As a result, more or fewer atoms and particles are knocked out of target 3 , in particular from regions 13 , 14 , 32 and 33 . The atomized atoms or particles migrate predominantly in the direction of the substrate 1 , where they are deposited as a thin layer 2 .

The target 3 consists of a central part 3 a made of a material with high affinity for the reactive gas, for example Si, and a frame-shaped part 3 b made of a material with low affinity for the reactive gas, for example Sn.

During the sputtering process, this configuration and material selection and corresponding magnetic fields and a coordinated ratio of oxygen to argon ensure that Sn is predominantly deposited as an electrically conductive material at the aperture 24 , while the layer 2 on the substrate 1 is predominantly made of pure SiO ₂ (silicon dioxide) builds up.

A process computer can be provided to control the arrangement shown, which processes measurement data and issues control commands. For example, the values of the measured partial pressure in the process chamber 15 , 15 a can be fed to this process computer. Based on this and other data, he can regulate the gas flow from the containers 16 , 17 via the valves 18 , 19 and adjust the voltage at the cathode 5 , for example. The process computer is also capable of all other variables, e.g. B. cathode current to regulate. Since such process computers are known, a description of their structure is omitted.

The in the device described during the loading process on the area around the cathode - in particular the inside of the screen 24 - applied, predominantly metallic (and thus electrically conductive) layer ensures that all charge carriers are removed from the vacuum or sputtering chamber 25 be, which then causes a stable sputtering process.

Fig. 2 shows a round target 35 , which is a special embodiment of the multi-part target 3 shown schematically in Fig. 1. The target 35 consists of a hollow cylindrical target body which is divided into three areas; a middle part 35 a made of a material with a high affinity for the reactive gas, for example Si, and two parts 35 b, each of which adjoins the end faces of the middle part 35 a in the axial direction and which consists of a material with a low affinity for the reactive gas, for example Sn, consist.

By reaction of the material from the middle part 35 a with the reactive gas (for example O ₂ ), a reaction product, for example SiO _2, arises in the main sputtering zone, which corresponds in its extension to the middle part 35 a. If you choose the material for the two parts 35 b so much "noble", for example Sn, so that with the amount of reactive gas that is just sufficient for the reaction of the material from the middle part 35 a, for example Si with the reactive gas, there is between the material of the two outer regions 35 b and the reactive gas no longer take place. This means that the surroundings of the end zones 35 a and 35 b of the targets 35 remain conductive.

In Fig. 3 is a hollow cylindrical tubular cathode 36 rotatable about its longitudinal axis, which is connected on the one hand to a voltage supply 37 and on the other hand has a circular arc-shaped, stationary arrangement of magnet pairs 38 on its inside. The cathode 36 is provided over its entire outer surface with a target material 38 to be sputtered, for example Si. Due to the fact that electrical power densities which differ locally on the target 39 , locally differentiated, for example SiO ₂ and Si, is deposited with the same target material 39 and reactive gas; Si is preferably deposited on a permanently installed surface, which serves as a permanently conductive anode 40 , while SiO ₂ preferably condenses on a substrate 41 to be coated.

Fig. 4 shows the rotating tube cathode 36 from the direction of the anode 40 of FIG. 3 in a perspective view. The two sputter trenches 42 and 43 , in the form of so-called "racetracks", have coupled magnetic tunnels which are in equilibrium on the middle path in each case (see direction of electron travel E). The higher power density also arises here.

A magnet assembly for a putter digging side in FIG. 5 consists of a disc-shaped portion of a target 49 with a bottom on the centrally arranged bore which serves to receive a cylindrical magnet 45. On the end of the magnet 45 projecting from the target disk 44 , a disk-shaped yoke 46 is applied, from which the magnetic field lines 47 extend to the north pole of the magnet 45 .

A parallelepipede cathode 48 , as shown in FIG. 6, consists of a target material 48 , in which the "Racetrack" main trench 50 is formed, and a multiplicity of smaller areas made of a second material, in which the secondary trenches 51 , 51 ' , .. form, as they are already shown in Fig. 5. These are left around the main trench 50 in the surface of the target 49 , the target areas 44 being made of a “nobler” material than the target 48 .

In Fig. 7, a planar target 52 is shown, which consists of a uniform material and on the side facing away from the substrate magnets 53 a, 53 b are provided, which are slidably arranged in positions 53 a, 53 b. Between the target 52 and the substrate 57 a, the orifices 54 a and 54 b acting as anodes are arranged such that they leave the middle area between the target 52 and the substrate 57 a free. Under operating conditions, the sputter trenches 55 a and 55 b are set on the side of the target 52 opposite the magnets 53 a, 53 b, and by adding a reactive gas, the sputter product is oxidized through and strikes as a layer 57 on a substrate located below the aperture 56 57 a down.

In a clocked mode of operation, ie the magnets 53 a, 53 b are moved on the target 52 outwards into the positions 53 a, 53 b relative to the part 52 of the diaphragms 54 a and 54 b which is parallel to the main direction of extension of the target, arises further sputter trenches 58 a and 58 b. By increasing the electrical Sputterlei stung or reducing the amount of reactive gas supplied or by simultaneous application of both measures, a metallic sputter product is obtained, which is now reflected as layer 54 c on the inside of the surrounding panels 54 a and 54 b and their function as electrically conductive anodes ensures.

The use of the displaceable permanent magnets 53 a, 53 b can be partially or completely replaced by controllable electromagnets or by controllable coils, which considerably simplifies practical use.

Reference symbol list

1 substrate
2 layer
3 , 3 a, 3 b target
4 plate, copper plate
5 electrode
6 yokes
7 magnet
8 magnet
9 magnet
10 DC power source
11 inductance
12 inductance
13 Sputtergraben (area)
14 Sputtergraben (area)
15 , 15 a coating chamber, recipient
16 gas containers
17 gas tanks
18 valve
19 valve
20 inlet connection, argon inlet
21 inlet connector, reactive gas inlet
22 gas supply line
23 gas supply line
24 , 24 a aperture, opening
25 containers, vacuum chamber
26 aperture
27 electrical connection (ground line)
28 electrical connection
29 capacitor
30 magnet
31 magnet
32 Sputter trench
33 Sputter trench
34 capacitor
35 , 35 a, 35 b round target
36 tube cathode
37 Power supply
38 magnet
39 target
40 anode
41 substrate
42 Sputter trench
43 Sputter trench
44 target
45 magnet
46 yoke
47 magnetic field lines
48 cathode
49 target
50 main sputtering trench
51 , 51 ′ side sputtering ditch
52 target
53 a, 53 ′ a, 53 b, 53 ′ b magnet
54 a, 54 b aperture, anode
54 c layer
55 a, 55 b Sputtergraben
56 aperture
57 , 57 a layer, substrate
58 a, 58 b Sputtergraben
E electron direction

Claims (5)

1. Method and device for the reactive coating of a substrate ( 1 , 41 , 57 a), for example with silicon dioxide (SiO ₂ ), consisting of a current source ( 10 , 37 ), which with a coating chamber ( 15 , 15 a) arranged, magnets ( 7 , 8 , 9 , 30 , 31 , 38 , 45 , 53 a, 53 b) a closing cathode ( 5 , 36 , 48 ) is connected, which is electrically connected to a target ( 3 , 35 , 39 cooperating, 44, 49, 52) which is sputtered and whose zer dusted particles a) deposited on the substrate (1, 41, 57, wherein in the coating chamber (15, 15 a) a process gas and a reactive gas such. B. argon and oxygen, can be introduced and the target to be atomized ( 3 , 35 , 39 , 44 , 49 , 52 ) is multipart lig, with a central, the substrate ( 1 , 41 , 57 a) opposite part ( 3 a, 35 a) of the target ( 3 , 35 , 39 , 44 , 49 , 52 ) is formed from a more reactive material than the part ( 3 a, 35 a) surrounding or framing this central part ( 3 b, 35 b), whereby A diaphragm ( 24 , 54 ) is provided between the substrate ( 1 , 41 , 57 a) on the one hand and the multi-part target ( 3 , 35 ) on the other hand, with a central opening ( 24 a, 56 ), which approximately corresponds to the configuration of the central target part ( 3 a, 35 a) and wherein a reactive gas inlet ( 21 ) and a process gas inlet ( 20 ) or a common inlet for both gases are provided and the magnetic field of the cathode ( 5 , 36 , 48 ) is formed such that during the coating process sputtering of the more reactive target material ( 3 a, 35 a) and the less reactive target at the same time materials ( 3 b, 35 b) is effected according to patent ............... (P 40 25 231.0), characterized in that the multi-part target ( 35 ) consists of a hollow cylindrical central part ( 35 a) consists of a material with a high affinity for reactive gas, for example Si, and consists of two hollow cylindrical outer parts ( 35 b), each of which adjoins the outside in the axial direction on the end faces of the central part ( 35 a) and which are made of one material have low affinity for the reactive gas, for example Sn. 2. Method and device for reactive coating of a substrate ( 1 , 41 , 57 a), for example with silicon dioxide (SiO ₂ ), consisting of a current source ( 10 , 37 ), which with a magnet arranged in an evacuable coating chamber ( 38 ) including a tubular cathode ( 36 ) which electrically cooperates with a target ( 39 ) which is atomized and whose atomized particles are deposited on the substrate ( 41 ), a process gas and a reactive gas, for. B. argon and oxygen, can be introduced, characterized in that the tubular cathode ( 36 ) on its surface to be coated ( 41 ) facing th, radially outer circumferential surface has zones under different power density, with an anode ( 40 ) in a zone of higher power density , which is arranged below and parallel to the axial direction of the tube cathode ( 36 ) and whose base is smaller than the projection area of the cylindrical target and can be coated with target material in metallic fashion (electrically conductive) and in a zone of low power density, a layer of oxidic target material, preferably on the substrate to be coated ( 41 ), is condensable. 3. The method and device according to claim 2, characterized in that a planar cathode on its surface to be coated ( 41 ) facing the outer surface has zones of different Sputterleistungsdich te, wherein in the zone of higher power density an anode ( 40 ) below and in parallel arranged to the planar cathode and can be coated with target material in metallic mode (electrically conductive) and in a zone of low power density a layer of oxidic target material, preferably on the substrate ( 41 ) to be coated, can be condensed. 4. Method and device for the reactive coating of a substrate ( 1 , 41 , 57 a), for example with silicon dioxide (SiO ₂ ), consisting of a current source ( 10 , 37 ), which is arranged with a coating chamber ( 15 ) which can be evacuated , Magnetic cathode ( 5 , 36 , 48 ) is connected, which cooperates electrically with a target ( 3 , 35 , 39 , 44 , 49 , 52 ), which is atomized and whose atomized particles on a substrate ( 1 , 41 , 57 a) precipitate, wherein in the coating chamber ( 15 ) a process gas and a reactive gas, for. B. argon and oxygen, can be introduced, marked net by a flat target ( 49 ), which is formed in places from a material which has a lower affinity to oxygen than that of which the target consists, and these locations ( 44 ) are arranged around a main sputtering trench ( 50 ), an aperture arrangement being designed in such a way that the material has a lower affinity for oxygen, e.g. B. Sn, mainly applied to this aperture in metallic fashion (electrically conductive) and the rest of the material, for. B. Si, through the aperture on the substrate as an oxide, for. B. SiO ₂ , can be applied. 5. Method and device for reactive coating of a substrate ( 1 , 41 , 57 a), for example with silicon dioxide (SiO ₂ ), consisting of a current source ( 10 , 37 ), which with an in a evacuable coating chamber ( 15 ) arranged , Ver sliding magnets ( 53 a, 53 b) including cathode is connected, which cooperates electrically with a target ( 52 ), which is atomized and whose atomized particles are deposited on the substrate ( 1 , 41 , 57 a), wherein in the coating chamber ( 15 ) a process gas and a reactive gas, e.g. B. argon and oxygen, can be introduced, and that the Magne te ( 53 a, 53 b) on the substrate ( 57 a) facing away from the target ( 52 ) are arranged displaceably, and that sputtered in a clocked mode of operation, the magnets ( 53 a, 53 b) being cyclically displaceable from a central area ( 53 a, 53 b) to an edge area ( 53 ′ a, 53 ′ b), characterized in that when the magnets ( 53 a, 53 b) in a central area, an oxidic sputter product can be condensed as a layer ( 57 ) on the substrate ( 57 a) in a area which is determined by an aperture opening ( 56 ) which extends in a plane which extends between the target ( 52 ) and the substrate ( 57 a) and runs parallel to both ver, and that with an arrangement of the magnets ( 53 'a, 53 ' b) in an edge area by additional increase in sputtering power or reduction in the amount of reactive gas supplied or by both measures a metal at the same time Isches sputter product as a layer ( 54 c) on the inside of the aperture ( 54 a and 54 b) facing the target ( 52 ) is condensable.