RU2507308C1 - Application method of thin-film coatings, and process line for its implementation - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: substrates are located on rotating drums that are moved in series along treatment zones of a process line at an equal constant linear and angular speed. With that, the ratio of linear and angular speeds of the drum is chosen so that each point of the drum surface can perform at least two complete revolutions at passage of the treatment zone. The process line includes air-lock, buffer chambers and at least one technological chamber with a process device, holders of substrates and a conveying system. The holders are located on carriages installed with possibility of series passage through the chambers. Each holder of the substrates is made in the form of a rotating drum. The carriages have the possibility of being moved at a constant linear speed.

EFFECT: providing possibility of treatment both of flexible large-sized substrates and substrates of a small size with high uniformity degree of a coating.

10 cl, 4 dwg

Description

Technical field

The group of inventions relates to the field of technological equipment for surface treatment in mass production, in particular, vacuum technological equipment intended for applying thin-film coatings with specified optical, electrical and other characteristics.

State of the art

The prior art various methods of applying thin-film coatings on the workpiece (substrate).

US Pat. No. 4,851,095, published July 25, 1989, describes a method for magnetron sputtering thin-film coatings on substrates placed on a rotating drum. Coatings are sprayed onto substrates by working devices located in a vacuum chamber around the drum.

The disadvantages of this technical solution include low productivity and significant cost of products, due to the need to repeat technological operations to achieve the required number of layers in the structure.

The closest set of essential features to the claimed method is disclosed in US Pat. No. 6,893,544, published May 17, 2005, a method for applying thin-film coatings in which the substrates are mounted on a vertical flat carrier carriage movable in a linear-type technological device (magnetron sputtering cathodes, linear sources plasma, etc.).

The disadvantages of this method are the high cost and low productivity, especially in the case of complex and precision coatings, due to the need for complex control and adjustment systems (i.e., unproductive losses of time and materials), high material consumption due to the fact that the processing zone of the technological device is larger areas of uniformity and, for example, with magnetron sputtering, from 30 to 50% of the target material goes past the substrates, as well as a limited range of applicable technologies and technological devices, as only devices that provide acceptable uniformity can be used, which makes a wide range of promising technologies inapplicable.

The prior art various installations for applying thin-film coatings on the workpiece (substrate).

In particular, for processing small-sized substrates in mass production, batch drum sets are used, such as, for example, the setup described in US Pat. No. 4,851,095, published July 25, 1989, which includes a holder for substrates, which is a cylinder along which a substrate is mounted. The uniformity of the coating in one direction is ensured by the rotation of the drum, in the second - by the use of linear technological devices.

In the display industry, where flat substrates are processed, in-line type equipment is used. As an example of such equipment, where the substrates are mounted on a carrier carriage moving along successively arranged technological steps, we can cite an automated installation for the formation of thin-film coatings, disclosed in the patent for utility model RU 78785, published on December 10, 2008. However, this device, as well as the equipment of the passage type known today, has inherent disadvantages such as low operational reliability due to the dependence of the reliability of mounting the substrates on the smooth movement of the transport system, and high cost associated with the presence of complex control and adjustment systems to ensure the required uniformity of applied coatings.

The closest set of essential features to the claimed invention is the production line for applying thin-film coatings described in US patent 6,893,544, published 05/17/2005, including sequentially located airlock chamber, a process chamber with a technological device located in it, an output buffer chamber and a flat substrate holder made with the possibility of movement along the chambers.

This technical solution has the following disadvantages:

- a limited range of sizes of the processed substrates, in particular, the impossibility of processing flexible substrates, for example, thin glasses, due to the inability to ensure their reliable fastening and safety when moving along the production line;

- high cost, due to the presence of complex control and adjustment systems, especially for complex and precision coatings, and the significant material consumption of the applied material, from 30 to 50% of which is sprayed off the substrate due to the uniformity of the applied layer due to the processing zone of the technological device more uniformity zone;

- a limited range of applicable technologies and technological devices, since the possible application is limited by the requirements for acceptable uniformity of the applied layer.

Disclosure of invention

The task to which this group of inventions is directed is to create a high-performance unified equipment for processing substrates of a wide range of sizes.

When solving this problem, a technical result is achieved, which consists in providing the possibility of processing both flexible large-format substrates and small-sized substrates with a high degree of uniformity of coating, with the possibility of using a wide range of technologies and technological devices, as well as with high efficiency of the useful use of the applied materials.

The specified technical result is achieved due to the fact that the method of applying thin-film coatings on substrates includes arranging the substrates on the holders and sequentially moving the holders with the substrates through process chambers, in which the coating is applied by means of technological devices located in the processing zone of the chambers, while the substrate holders are made in the form of rotating drums that move through technological chambers parallel to the axis of rotation of the drums and rotate with the same howl constant linear and angular velocity, and the ratio of linear and angular velocities are selected such that every point of the drum surface performs at least two complete revolutions during the passage of the treatment zone ..

где f_cp - среднее значение f(x), M₂ - максимальное значение f'(x). Эта оценка является оценкой неравномерности толщины покрытия в условиях стабильной работы технологического устройства.The principle of achieving uniformity, implemented in the development, is explained by the example of a description of the motion of a cylindrical holder that performs uniform rotational-translational motion through a technological zone with one device. When the cylinder moves, at each point on the surface of the cylinder that makes up its generatrix, a certain coating thickness f (x) will be applied in one revolution. At each revolution, each considered point A will be shifted by the displacement step of the cylinder d to point A ', and at the next revolution, the coating thickness corresponding to point A' will be applied in it. The total thickness T deposited at point A when passing through the entire technological zone will be obtained by summing the values of the constructed graph at points with a step d. This summation is equivalent to integrating the graph using the middle rectangle method with step d. For another point B, the same summation is obtained, but over a different set of points. Those. for any point, an estimate of the total thickness applied is given by T ₀ = S / d, where S is the area under the graph. The accuracy of this estimate increases with decreasing step in proportion to its square. The relative error estimate is given by $$R\le \frac{{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="00000006.png"\; state="\{\{state\}\}">m</figure-callout>}}_2}{24f_{\mathrm{<figure-callout\; id="2"\; label="c\; p\; d"\; filenames="00000006.png"\; state="\{\{state\}\}">c\; </figure-callout>}p}}{d}^{}{}^2,$$

where f _cp is the average value of f (x), M ₂ is the maximum value of f '(x). This assessment is an assessment of the unevenness of the coating thickness in conditions of stable operation of the technological device.

. Если теперь совместить все точки суммирования, то получится, что суммируются значения в точках с шагом d/N. Т.е. применение такой конфигурации устройств эквивалентно уменьшению шага интегрирования в N раз, и, соответственно, улучшению равномерности в N² раз. Требуемая равномерность может быть достигнута за счет того, что:When using N identical technological devices uniformly arranged around the substrate holder, the previous calculation is valid for a separate technological device, which can be repeated by numbering the technological devices sequentially from 1 to N. Moreover, for each point, the contribution of the kth technological device will be determined by the sum values at points offset from the first by $$d\times \frac{k-\mathrm{one}}{N}$$

. If we now combine all the summation points, it turns out that the values at the points in increments of d / N are summed. Those. the use of such a configuration of devices is equivalent to reducing the integration step by N times, and, accordingly, improving uniformity by N ² times. The required uniformity can be achieved due to the fact that:

- around the substrate holders several identical technological devices can be symmetrically located;

- several identical devices can be located along the path of the substrate holders with a step S = (m + 1 / n) * d, where m is an integer, n is the number of devices, d is the linear movement of the substrate holder during one revolution;

- part of the spraying zone can be masked by an externally controlled damper.

The specified technical result is also achieved due to the fact that in the production line for applying thin-film coatings containing airlocks, buffer chambers and at least one technological chamber with a technological device, substrate holders located on carriages mounted with the possibility of sequential passage of cameras, and transport system, each holder of substrates is made in the form of a rotating drum mounted on a carriage coaxially with the direction of its movement, while the drums are made rotatable with constant angular velocity and carriages are arranged to move with constant linear speed and providing at least two full revolutions of each point on the surface of the drum when passing through the processing zone. In this case, the production line may contain input lock and buffer chambers and output buffer and lock chambers.

The specified technical result is also achieved due to the fact that the carriage of the substrate holder can be made in the form of a suspension located above the cylinder, or in the form of a frame, or in the form of a trolley with linear guides located under the cylinder.

In addition, the production line can be equipped with at least one rotary drum drive, and the drums can be equipped with friction and / or magnetic detachable couplings and / or a low-voltage motor.

The specified technical result is also achieved due to the fact that each substrate holder can be equipped with an electric motor, and the transport system is equipped with rollers, and the carriage with guides interacting with the rollers.

Brief Description of the Drawings

The invention is illustrated by drawings, where:

figure 1 presents a graph of the distribution of the thickness applied per revolution from one technological device is shown on the graph (coordinates along the X axis - in mm, from the center of the device);

figure 2 shows the holder of the substrates;

figure 3 shows a magnetic coupling;

figure 4 shows a General diagram of a production line;

The best embodiment of the invention

The claimed method of applying thin-film coatings on substrates can be illustrated by the example of the organization of technological devices of the line for applying a four-layer antireflection coating on glass. The requirements for uniformity of the layers are ± 1% for the first and second layers, and ± 3% for the third and fourth layers.

The length of the holder of the substrates is 100 cm, the speed of movement of the holders in the technological zone is determined by the tact of the line, and is 1 m / min.

Four technological zones are organized for coating, one zone for each layer. As technological devices, medium-frequency magnetrons with a target length of 800 mm are used. The number of technological devices is determined by the performance requirements and layer thicknesses. To apply the first layer (silicon oxide), one technological device 01 is used, the second layer (titanium oxide) - two technological devices 02, the third (silicon oxide) and the fourth (titanium oxide) layers - four technological devices 03 and 04, respectively.

Because the first two layers have more stringent requirements for uniformity, and for applying the first layer, the smallest number of technological devices is used, the rotation speed necessary for uniformity will be determined by the first layer.

An example of the distribution of thickness applied per revolution from one technological device is shown in the graph (Fig. 1), where the coordinates along the X axis are in mm, from the center of the device.

According to the schedule, the length of the treatment zone is 120 cm, while the length of the edge zones in which the thickness decreases to zero is about 10 cm.

At two turns of the substrate holder during the passage of the treatment zone, the unevenness will be about ± 35%: the minimum thickness will be at the point that will fall on the edges and at the center of the treatment zone, the maximum will be at one of the points that will fall into the treatment zone twice. The ratio of these thicknesses will be approximately 1: 2, which gives an unevenness of ± 33%.

.To achieve the required uniformity, it is necessary to reduce this value by 35 times, which gives an estimate of the required number of revolutions $$2*\sqrt{}35\approx 12$$

.

A more accurate estimate according to the schedule shows that with such a number of revolutions, the unevenness will be ± 0.8%.

Based on this, the rotation speed of the substrate holder should be set such that the linear displacement of the holder per revolution is no more than 120 / 12≈10 cm. At a translational speed of 1 m / min, the rotation speed is selected at least 10 rpm.

For the remaining layers, better uniformity will be obtained, as the use of 2 or more identical technological devices is equivalent to a proportional increase in rotation speed, i.e. improve uniformity.

The operation of the claimed production line can be considered as an example of a linear arrangement with two-stage locking, including a substrate holder, a vacuum shutter, an entrance lock chamber of a low vacuum, an entrance lock chamber of a high vacuum, an entrance buffer chamber, a processing chamber, an output buffer chamber, an exit lock chamber of a high vacuum, low-pressure outlet lock chamber, transport system with drive rollers, high-vacuum pumps and technological devices.

The substrate holder is a drum (1) mounted in bearings on a carriage (2). The substrates, for example, glass, are attached to the plates (3) by any known method, ensuring their reliable fixation during rotation of the drum.

The carriage is equipped with guides (10) located under the drum and mounted on racks (11) of dielectric material.

In some cases, depending on the applicable technological process, the carriage (2) can be performed:

- in the form of a trolley when the linear guides are located under the drum;

- in the form of a suspension, when the linear guides are located above the drum;

- in the form of a frame when the linear guides are located on opposite sides of the drum.

- or in another way that allows linear movement of the rotating cylinder.

At the ends of the drum shaft, elements of a detachable magnetic coupling (4) and (5) are installed. The coupling device is well known. The first element of the detachable clutch (4) is a hollow cylinder of soft magnetic material, on the inner surface of which magnets are fixed (6). The magnets are mounted with alternating polarity, with the directions of magnetization indicated in the figure. The response element of the magnetic coupling (5) is a cylinder of soft magnetic material with magnets (7) fixed on its surface, the number of which coincides with the number of magnets of the first element. The magnets are mounted with alternating polarity with the directions of magnetization indicated in the figure. Between the magnets of the first and second elements there is a gap of about 5 mm, which ensures that there is no contact when scrolling the coupling under conditions of inaccurate joining of the substrate holders.

To maintain the rotation of the drum, a direct-drive electric drive is used. The rotor of the electric drive (8) is formed by an annular magnetic circuit with magnets mounted on it. The stator of the electric drive (9) with the control unit is located on the carriage frame. The electric drive is supplied with direct current through linear guides of the carriage (10). For this, linear guides are mounted on the carriage on insulating posts (11). Power to the linear guides is transmitted through the rollers of the transport system.

The technological line consists of an entrance lock chamber of a low vacuum (14), an entrance lock chamber of a high vacuum (15), an input buffer chamber (16), technological chambers (17) with technological devices installed in them, an output buffer chamber (18), and an exit lock high vacuum chambers (19), and a low vacuum exit lock chamber (20).

Technological devices are installed along the movement of the substrate holders and the processing zone is defined as the region along the movement of the substrate holders in which the technological device is located, and within which the main part (more than 90%) of the material applied by this device falls on the substrate holder. Moreover, several technological devices intended for applying the same material, forming partly or completely overlapping treatment zones, are considered as one technological device. If necessary, several technological devices involved in the deposition of the layer can be installed around the substrate holders.

The holder (22) with the substrates fixed on it enters the inlet lock chamber (14), after which the door (21) of the lock chamber is closed. After closing the door, the holder moves back and its detachable clutch (4) engages with the counterpart of the clutch (23), mounted on the shaft of the vacuum input of rotation of the engine (24), mounted on the door of the lock chamber, and driven by an electric motor (25).

The electric motor spins the drum of the substrate holder to a predetermined rotation speed; at the same time, the airlock is pumped out to a pressure of 10-20 Pa.

After pumping and unwinding the drum, the transport shutter (25) opens, the carriage holder moves to the high-pressure inlet lock chamber (15), and the shutter (25) closes. The lock chamber of high vacuum is equipped with turbomolecular pumps (26), and pumping to pressure <0.01 Pa occurs in it.

After pumping out the high vacuum lock chamber, the transport shutter (27) opens, the substrate holder moves to the input buffer chamber (16), and the shutter (27) closes. In the buffer chamber, the substrate holder slows down to the technological speed, and is joined with the substrate holder, which entered the production line at the previous cycle. The magnetic couplings of the substrate holders are engaged and the rotation of the incoming substrate holder is synchronized with the rotation of the substrate holders (28) going through the process chamber. In the technological chamber, the rollers of the transport system are supplied with power, so that the motors of the substrate holders support the rotation of their drums.

When passing through technological chambers (17), a coating is applied to the substrates. In the process of processing the substrate (when passing through the processing zone), the drum rotates and moves uniformly along its axis. The substrate holders move through the treatment zones with a minimum gap between each other.

Considering that uniformity is mainly determined by the displacement step per revolution, the ratio of the linear displacement speed and the rotation speed of the substrate holder is set so that each point on the surface of the substrate holder makes at least two full revolutions when passing the processing zone. Thus, the displacement step during one revolution is small enough and allows to obtain high uniformity of the applied coatings regardless of the types of technological devices used, including linear and point ones.

The task of ensuring the required rotation speed of the substrate holder during processing with simultaneous linear movement can be implemented in one of the following ways:

1. The substrate holder is untwisted to the required speed by an external drive in one of the input chambers with the carriage stationary, and further retains rotation due to inertia.

2. Each carriage is equipped with a low voltage electric motor. Power is supplied to the electric motor through the rollers of the transport system or individual contact rollers to the linear guides of the carriage isolated from the carriage body.

3. The substrate holder is untwisted to the required speed by an external drive in one of the input chambers with the carriage stationary, while the carriage is equipped with a low-voltage electric motor, which is used only to maintain rotation, and can be of very low power.

To ensure the same speed of rotation of all substrate holders in the processing zone, they can be equipped with friction or magnetic detachable couplings, providing rotation transfer between adjacent substrate holders during their movement with a minimum clearance.

For the deposition of metal-dielectric and composite metal-dielectric coatings, in addition to the installations traditional for equipment of the through-type type, one of the following methods can be used, namely, the multiple deposition of thin metal or under-oxidized layers with subsequent oxidation.

In this case, by oxidation is meant any reaction leading to the formation of a chemical compound, for example, with oxygen, nitrogen, selenium, etc.

For this, a special technological zone is formed in which technological devices for depositing one or several metals are installed around the holder, and a technological device for oxidation, which is a source of activated reactive gas (for example, a plasma source).

High-vacuum pumping facilities are installed in the technological zone, providing gas separation between the technological oxidation device and technological devices for applying metals. This ensures a stable and high-performance operation of technological devices for the deposition of metals.

When passing through this technological zone, each point of the processed surface repeatedly successively passes by technological devices for applying metals, where an ultrathin layer of material is applied, and by a technological oxidation device, where this layer is completely oxidized. After passing through the technological zone, the treated surface is uniformly coated with a metal-dielectric or composite metal-dielectric coating with a given composition.

Technological devices can apply one or different materials. In the latter case, the deposition rate of materials can be set different, to obtain coatings of the desired composition.

After passing through the technological chambers (17), the substrate holder exits into the output buffer chamber (18).

The transport shutter (29) opens, the substrate holder accelerates, breaking away from the next substrate holder, and moves to the high-pressure exit lock chamber (19); after which the shutter (29) closes, the transport shutter (30) opens, and the substrate holder moves to the low-pressure outlet lock chamber (20), where the front element of the magnetic clutch of the holder is mated with the response element of the magnetic clutch (31) mounted on the door. The magnetic coupling element (31) is mounted on a shaft, the rotation of which is difficult due to friction.

The shutter (30) closes, drained air is introduced into the chamber, the pressure rises to atmospheric. At this time, due to braking of the coupling (31), the drum of the substrate holder stops.

After equalizing the pressure in the outlet lock chamber (20) with the atmospheric one, the door (32) of the chamber opens, and the substrate holder exits their processing line.

Claims (10)

1. A method of applying thin-film coatings to substrates, including arranging the substrates on the holders and sequentially moving the holders with the substrates through the process chambers, in which the coating is applied by means of technological devices located in the processing zone of the chambers, characterized in that the substrate holders are made in the form of rotating drums while the drums are moved through the technological chambers parallel to the axis of rotation of the drums and rotate with the same constant linear and angular scab, wherein the ratio of linear and angular velocities are selected such that every point of the drum surface performs at least two complete revolutions during the passage of the treatment zone. 2. A production line for applying thin-film coatings, comprising airlock, buffer chambers and at least one technological chamber with a technological device, substrate holders located on carriages mounted with the possibility of sequential passage of cameras, and a transport system, characterized in that each substrate holder made in the form of a rotating drum mounted on the carriage coaxially with the direction of its movement, while the drums are rotatable with a constant angular orostyu and carriage are movable at a constant linear velocity and providing at least two complete revolutions each point of the drum surface by passing the treatment zone. 3. The production line according to claim 2, characterized in that it comprises input gateway and buffer chambers and output buffer and gateway chambers. 4. The production line according to claim 2, characterized in that the carriage of the substrate holder is made in the form of a suspension located above the cylinder. 5. The production line according to claim 2, characterized in that the carriage of the substrate holder is made in the form of a frame. 6. The production line according to claim 2, characterized in that the carriage of the substrate holder is made in the form of a trolley with linear guides located under the cylinder. 7. The production line according to claim 2, characterized in that it is equipped with, but at least one drum rotation drive. 8. The production line according to claim 7, characterized in that the drums are equipped with friction, and / or magnetic detachable couplings, and / or a low-voltage electric motor. 9. The production line according to claim 2, characterized in that each substrate holder is equipped with an electric motor. 10. The production line according to claim 2, characterized in that the transport system is equipped with rollers, and the carriage has guides interacting with the rollers.

Images