SU1257115A1 - Evaporator - Google Patents

Description

 1257115

refers to application

NO NO

coatings in vacuum and can be used to spray films of expensive materials for elements of integrated circuits.

A device for applying films in vacuum, containing a crucible with an outlet shaped channel, is known, the crucible and the outlet channel being placed in a radiating thermal block.

Such a device does not provide a sufficiently low flow of material due to the fact that particles in the outgoing vapor flow are diffusely reflected from the walls of the exit channel, i.e. with the loss of the initial speed of the directional flow.

Also known is a directional evaporator containing a crucible, a removable symmetrical steam line emitting n collimating diaphragms, a heater and heat shields.

The upper part of the steam line, not the yogi in the heater, has a lower temperature than the lower part and the crucible. Therefore, the material from the outer layers of the steam flow coming out through the steam line, which does not fall on the Podolолska, is deposited on the inner surface of the upper part of the steam line. After spraying with new. When loading the material, the steam line is installed so that the condensed material is at the bottom and is used in such a subsequent sputtering cycle. Thanks to it in such an evaporator the consumption is reduced. steam material.

A disadvantage of the known evaporator is the low sputtering rate, which is limited by the appearance of splashes when it is raised. The appearance of sprays is due to the fact that during spraying the temperature of the steam line varies from the evaporation temperature in the lower part of the steam line to the condensation temperature in the upper part, the passage of all values between these temperatures, including the temperature at which condensation occurs in the liquid phase. This phase is predominantly in the form of droplets, which, with an increase in the deposition rate, captured the passage of the shielding through the steam line, the flow and transfer to the surface of the substrate. Channels of micron size on the substrate appear already at a deposition rate of 70 L / s.

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Research institute for spraying rate by increasing the evaporation temperature NIL droplet size increases.

This evaporator also has a large overall diameter of the entire sprayed film with a small size of the useful spray area, t, e. areas in which the unevenness of the film thickness is acceptable for the placement of printable substrates in it. As a consequence, it increases the consumption of evaporated material.

The purpose of the invention is to increase the sputtering rate and reduce the consumption of evaporated material.

This goal is achieved by the fact that in the evaporator containing the crucible there is a removable symmetrical steam line with an emitting and. the collimating diaphragm, the heater and heat shields, the emitting diaphragm placed in the middle part of the steam line, the heat shields are located on both sides of the emitting diaphragm ODD versus the other, and the heater covers the steam line to the level of the heat shields on the side of the crucibles, and the hole in the emitting diaphragm is designed as a descent beam - flow nozzle, and the steam line is equipped with two additional collimating diaphragms, located symmetrically on both sides of the emitting diaphragm, and the diaphragm is We are in the form of discs with annular slits.

Installing an emitting diaphragm with heat shields in the middle part of the steam line allows condensation to occur only in the solid phase, since the upper part (top condenser) of the steam line separated from the middle part by shields has a temperature below the melting point. The middle part of the steam line, together with the emitting diaphragm, is located in the region between the upper cut of the heater and the T-bar, a spruce in it. This area of the heater, due to the smaller heating cross-section provided by the shape of the slit, has a higher temperature and provides an additional supply of thermal energy to the middle part of the steam line, compensating for its increased losses due to radiation from the emitting diaphragm. Therefore, there is no condensation at all in the middle part of the steam line and the emitting diaphragm. The absence of a liquid phase in the middle part eliminates the possibility of trapping it.

312571

flow and transfer to the substrate, which increases the sputtering rate.

In addition, the presence of a diaphragm in the middle part of the steam line makes it possible to reduce the diameter of the entire area of the CRRD, on which the evaporated material is deposited, and thereby reduce the ratio of me;

effective area of the sprayed area, where

the required variation in film thickness is provided. At the same time, outside the useful area of the film, the film has a sharper decrease in thickness, which reduces the consumption of evaporated material.

The opening in the emitting diaphragm in the form of a converging-diverging nozzle eliminates turbulent eddies of the outflow at a high deposition rate and thereby increases the uniformity of the sprayed film. This leads to the expansion of the sprayed zone, and, consequently, to a reduction in the consumption of the sprayed material.

Collimating diaphragms with annular slits provide additional correction of the evaporator pattern. At the point lying in the center of the substrate, the part of the diaphragm, limited by an annular slot, obscures a certain part of the orifice of the emitting diaphragm. At a point offset from the center of the substrate, most of the aperture opens, i.e., its effective emitting surface increases, which compensates for the drop in the original radiation pattern of the emitting diaphragm. Holes can also be made in collimating diaphragms with cuts, making additional correction of the radiation pattern, and the uniformity of the applied films is significantly increased, which means that the useful area expands, i.e. reduced consumption of printed material.

In addition, the expansion of the useful area of the film when the film is applied to a substrate of a certain size makes it possible to reduce the distance from the evaporator to the substrate. The deposition rate also increases with this, as it varies inversely with the square of this distance.

Figure 1 shows the proposed; evaporator, incision; figure 2 - view And figure 1.

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The evaporator contains a substrate 1 located in a vacuum chamber and a heater 2 with a crucible 3 installed in it with evaporated material 4 and a removable symmetrical steam line. The steam line consists of a middle part 5 with an emitting diaphragm 6, the hole in which is made in the form of a converging-diverging nozzle 7, and capacitors 8 and 9, on the ends of which there are end-facing collimating diaphragms 10 and 11 with holes in the shape of the substrate and Additional collimating diaphragms 12 and 13 in the form of discs with annular slots and o / revs, mounted on molybdenum beams 14 and 15. The edge of the substrate and the holes in the front and emitting diaphragms lie on the straight line, indicated by a dot-dash line. The condensers are connected to the middle part of the steam line and to the emitting diaphragm by means of molybdenum pins 16. On either side of the emitting diaphragm 1 -. thermal shields were added 17.

The heater is surrounded by molybdenum screens 18 and screens 19 integrally formed with it. In addition, the heater has current leads 20, also designed to mount the entire device in standard holders of a vacuum unit. The T-shaped slit of the heater, indicated by a dotted line, ends at the level of the lower end of the emitting diaphragm, and the cross section of the heater in the upper part is smaller than in the lower part.

The evaporator can be made of MPG-6 graphite or other high-temperature material.

The proposed evaporator works as follows.

After evacuating the vacuum chamber and heating the substrate 1, the heater 2 is turned on and the crucible 3 with the evaporated material 4 is brought to operating temperature. The lower condenser 9 with the middle part of the steam pipe 5, the diaphragm 6 and the nozzle 7 is heated to the same temperature. t through the nozzle 7 and fall on the substrate 1. Part of the vapor that does not fall on the substrate 1, is deposited on the upper condenser 8, which has a lower temperature;

After the end of the cycle, the inserts change the substrate, and the crucible 3 is loaded.

The vaporized material is vaporized, and the steam line is turned over by the condenser 8 downward so that the material deposited in it is used in the next spraying cycle along with the material 4 in the crucible 3.

The end diaphragm 10 installed at the upper end of the steam line forms a flow in the hole with the configuration of the sprayed substrate 1, collecting material flying outside its limits. From the diaphragm 11 located in the crucible, at this time the material deposited in the previous printing cycle evaporates.

The diaphragm 12 collects a portion of the material flying to the center of the zone of pressure, and takes nothing or takes a smaller part of the material that flies to the edge of the useful spray area, increases the uniformity of the film and thus expands the useful spray area. From the diaphragm 13 located in the crucible, at this time the material deposited on it in the previous sputtering cycle is evaporated.

The voltage to the heater 2 is supplied through the current leads 20. Due to the smaller cross-section of the heater in the upper part, it has a higher temperature, compensating the additional 156

real heat loss in the middle part of the steam line.

The proposed evaporator with a steam line length of 70 mm and an inner diameter of 20. mm, as well as with a minimum nozzle diameter of 8 mm. Deposited on a 60x48 mm substrate provides a coefficient of useful use (TSS) of the evaporated material 24% with a spread of the deposited film thickness 2.5%, i.e. It allows a 2.4-fold reduction in material consumption compared with the known device with the same thickness variation. Installation at a distance of 14 mm from the nozzle of the diaphragm with an annular slot with an outer diameter of 20 mm and an inner 4.5 mm reduces the material consumption by another 1.75 times, providing a KPI of 42%. The end diaphragm with a hole in the shape of the substrate reduces consumption by 1.4 times (KPI-34%). The simultaneous installation of the end diaphragm reduces material consumption by 2.45 times, providing a KPI of 59%. Thus, in the proposed device, the material consumption is reduced by 5.9 times compared with the known.

A scree device is proposed to provide a deposition rate of 320 A / s, which is 4.5 times more than the known.

Compiled by V.Kazankov Editor N.Shvyschka. Tehred I.Popovich Proofreader V.Sinitska

Order A883 / 21 Circulation 878 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, Projecto st., 4

fpu3.2

Claims (3)

1. EVAPORATOR containing a crucible, a removable symmetrical steam pipe ς emitting and collimating diaphragms, a heater and heat shields, characterized in that, in order to increase the spraying rate and reduce the consumption of evaporated material, the emitting diaphragm is located in the middle part of the steam pipe, the heat shields are located along both sides of the emitting diaphragm are one opposite the other, and the heater covers the steam line to the level of the heat shields on the crucible side. 2. The evaporator pop. 1, characterized in that the hole in the emitting diaphragm is made in the form of a converging-diverging nozzle. 3. Evaporator according to claim 1, characterized in that the steam pipe is provided _with two additional collimation miruyuschimi diaphragms arranged symmetrically on both sides of the emitting aperture, wherein the aperture formed in the form of disks with annular slits.