Description:F O R M 2

THE PATENTS ACT, 1970
(39 of 1970)

COMPLETE SPECIFICATION
(See section 10 and rule 13)

TITLE
AUTOMATED SILAR UNIT FOR FABRICATION OF THIN-FILMS

INVENTORS
CHOLAKKOTTIL PRABHAKARAN, Deepak; CHALIYAMPURATH, Shyamlal; and SAMBASIVAM, Rajni Kamalam
School of Physical Sciences,
Amrita Vishwa Vidyapeetham, Coimbatore 641112, Tamil Nadu

APPLICANTS
AMRITA VISHWA VIDYAPEETHAM
Coimbatore Campus, Coimbatore- 641112,
Tamil Nadu, India

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED:

AUTOMATED SILAR UNIT FOR FABRICATION OF THIN-FILMS
CROSS-REFERENCES TO RELATED APPLICATION
[0001] None.
FIELD OF THE INVENTION
[0002] The disclosure generally relates to deposition of thin films and, in particular to an automated unit for fabrication of thin films.
DESCRIPTION OF THE RELATED ART
[0003] A thin film is a coating of material in the nanometer to micrometer range that is applied to a surface for a specificpurpose. Thin films offer a significant benefit over bulk or thickcoatings due to their high surface-to-volume ratio, allowingthem to be efficient when surface reactions are required. Roll coating, spray coating, dip coating, and other coating methods such as CVD and PVD are examples for thin-film synthesis. In comparison to other processes, the dip-coating approach is less expensive and can cover huge substrates, making it appropriate for industrial-scale applications. Successive ionic layer adsorption and reaction (SILAR) is a dip-coating method. SILAR employs a layer-by-layer deposition process in which ionic species sequentially adsorb and react on the substrate. It is reasonably cheap and can create various materials such as sulfides, composites, oxides, and chalcogenides.
[0004] In one cycle of the SILAR process, the cleaned substrate first goes into a cationic solution, then a wash solution, then a cationic solution, and another wash. Depending on the compound to be developed, we can alter the number of cationic and anionic solutions. The parameters that influence the SILAR method are the pH of the anionic and cationic solution, dipping time, number of cycles, the concentration of the ions in the solution, solvent, and nature of the substrate.
[0005] WO2017070764A1 describes an automatic apparatus for depositing thin films. IN201721000280 describes an automated equipment for deposition of thin film by dip coating and successive ionic layer adsorption and reaction and methods. IN823/CHE/2014 describes an apparatus for thin-film deposition using Chemical Vapour Deposition method. MX2014015593A describes a transport system for the deposition of ionic material films by immersion and operation method.
[0006] A new and improved model which is fully automated, low-cost and efficient is disclosed.
SUMMARY OF THE INVENTION
[0007] The disclosure relates to a device for automatic device for deposition of thin films.
[0008] In various embodiments, an automated device for dip coating and sequential ionic layer adsorption and reaction for deposition of thin films is disclosed. The device includes a disc resting on a base. The disc is configured to hold beakers containing solutions for dipping a substrate. The device includes a plurality of button magnets on the curved surface of the disc. The button magnets inserted along the line of beaker holdersand configured to stop rotation of the disc at proper points of dipping the substrate. The device includes a hall sensor switch configured to detect the magnet and to identify the location of beakers. The device further includes a plurality of rods attached perpendicular to the base and the other end is attached to a platform. A substrate holder is attached to the platform. The device includes a first motor to rotate the disc and a second motor to enable vertical movement of the substrate. The device further includes a microcontroller for automation of the device.
[0009] The device includes an end stop switchaffixed to the end of the rod and is configured to determine the location of the substrate to be coated. The first motor and second motor of the device is a bipolar stepper motor. One of the vertical rods is a threaded rod attached to the stepper motor to drive vertical motion of the substrate. The platformis a mobile platform and is configured to support the substrate. The device includes a first motor driver and a second motor driver along with a power supply to drive the motors. The device is configured to coat multiple substrates simultaneously. The disc is configured to hold beakers of varying size or number. The microcontroller is configured to automatically drive the device to perform a pre-programmed sequence or cycles of dipping duration in each solution.
[0010] This and other aspects are described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The invention has other advantages and features, which will be more readily apparent from the following detailed description of the invention and the appended claims, when taken in conjunction with the accompanying drawings, in which:
[0012] FIG. 1 illustrates an automated device for deposition of thin films, according to an embodiment of the present subject matter.
[0013] FIG. 2 illustrates the disc, hall sensor switch and button magnet, according to an embodiment of the present subject matter.
[0014] FIG. 3illustrates a view of the beaker holder and button magnet, according to an embodiment of the present subject matter.
[0015] FIG. 4illustrates the substrate holder and vertical rods of the device, according to an embodiment of the present subject matter.
[0016] FIG. 5 illustratesan arrangement for coating of multiple substrates, according to an embodiment of the present subject matter.
[0017] FIG 6illustrates the control configuration of the device, according to an embodiment of the present subject matter.
[0018] FIG 7A and 7B gives a representation of the base having four beakers and 8 beakers respectively.
[0019] FIG. 8 illustrates a representation of circuit diagram showing the working of the device.

DETAILED DESCRIPTION OF THE EMBODIMENTS
[0020] While the invention has been disclosed with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt to a particular situation or material to the teachings of the invention without departing from its scope.
[0021] Throughout the specification and claims, the following terms take the meanings explicitly associated herein unless the context clearly dictates otherwise. The meaning of “a”, “an”, and “the” include plural references. The meaning of “in” includes “in” and “on.” Referring to the drawings, like numbers indicate like parts throughout the views. Additionally, a reference to the singular includes a reference to the plural unless otherwise stated or inconsistent with the disclosure herein.
[0022] The present subject matter describes an automated sequential ionic layer adsorption and reaction (SILAR) unitfor thin-film deposition that is economical and efficient.
[0023] An automated device100 for dip coating and sequential ionic layer adsorption and reaction for deposition of thin films is illustrated in FIG. 1 to FIG. 6 according to embodiments of the invention. The device includes a disc 102 resting on a base 104. The disc is configured to hold beakers to contain solutions for dipping a substrate to be coated. The device includes a plurality of button magnets on the curved surface of the disc. The button magnets 106 may be inserted along the line of beaker holders108. The button magnets are inserted to stop rotation of the disc at proper points for dipping the substrate. The device includes a hall sensor switch 110 to detect the magnet andto identify the location of beakers as A plurality of rods 112, 114 may be attached perpendicular to the base and the other end of the rods may be attached to a platform116. A substrate holder118 may be attached to the platform.
[0024] In various embodiments, control configuration of the device is illustrated in FIG. 6. The device may include a microcontroller 150 for automation of the device. The device further includes a first motor 162to rotate the disc and a second motor164 to enable vertical movement of the substrate for dipping in a solution. The first motor 162 and second motor 164 may be bipolar stepper motors, according to one embodiment of the invention. For generating vertical motion, the threaded rod 112 and disc are driven by the second motor 164. The device includes two motor drivers 161 and 163 to drive the first 162 and second motors 164 respectively. Also included is a power supply 160 to power the control electronics and drive motors.
[0025] The device may be used for coating of multiple substrates, according to one embodiment of the invention. FIG. 5 illustrates an arrangement for coating of multiple substrates. Two vertical rods 121, 122 may be kept on two sides and two substrate holders 124, 126 arranged between the vertical rods, to enable two substrates to be coated simultaneously, for example.
[0026] The disc that holds the beakers may have variable capacity according to needs. According to various embodiments, the number and size of the beakers that the device can hold may be varied. The rods attached perpendicular to the base and the platform includes a threaded rod 112 and a smooth rod 114. A threaded T-nut and a linear ball bearing may be used for attaching the rods to the platform. The platform may be parallel to the base and the platform holds the substrate for dipping. This type of alignment enables vertical movement of the substrate for dipping. The movement assists dipping and rising of the substrate. The dipping is donesequentially in the solutions kept in the disc holder. The platform may be a mobile platform, according to one embodiment of the invention. An end stop switch 120 may be affixed to the end of the vertical rods, according to one embodiment of the invention. The location of the substrate that needs to be used for coating may be determined by the end stop.
[0027] The microcontroller 150 is configured to provide automation of the device. The microcontroller drives the device to perform a pre-programmed sequence or cycles for dipping the substrate in each solution. The number of cycles and dipping times in each solution may be left flexible in the code of the microcontroller. The microcontroller supplies the power for the operation of the device.
[0028] The device is fully automated, economical, and efficient which helps in easy thin-film deposition. It prevents human error and resolves tedious, lengthy tasks where there is high possibility of error. The adjustable disc allows the use of substrates of various sizes, and the number of anionic and cationic solutions may also be varied. Additionally, the dipping duration in each solution may be altered independently.
[0029] EXAMPLES
[0030] Example 1: Materials and methods
[0031] Arduino UNO was used as the microcontroller unit for the prototype. Two stepper motors were employed, which were controlled by L298 motor driver modules. The body of the SILAR unit was fabricated using acrylic sheets. Insulated copper wires and jumper wires were used for the connection. A 2V, 2A power supply was provided for the device to function. Two discs were made: one that can hold four beakers and another that can hold eight beakers. A disc that can hold 4 beakers of base 23mm, placed at right angles, another disc that can hold 8 beakers of base 23mm, placed at right angle is shown in FIG. 7A and FIG. 7B.
[0032] Example 2: Components and circuit
[0033] Arduino was used as the central processing unit. Arduino is an open-source platform for electronics that makes working with microcontrollers easy. It takes digital and analog inputs and processes them and gives signals to output devices as per user’s instruction. Arduino is an extendible open-source cross-platform which is inexpensive and simple to use. For the prototype development Arduino Uno was used which is a microcontroller-based board which uses an ATmega328p microcontroller which are widely used for automation and robotic application. L298 controllers were used for regulating the stepper motor. The stepper motors received power from an Arduino UNO. The sensors' sensor terminals were also connected to the Arduino. Stepper motor control modules, which were powered by 12 volts and 2 A, were connected to stepper motors. One of these modules also provided 5 volts for the Arduino to operate. To code, an Arduino IDE was employed. A circuit diagram for the working of the device is shown in FIG. 8.
[0034] Although the detailed description contains many specifics, these should not be construed as limiting the scope of the invention but merely as illustrating different examples and aspects of the invention. It should be appreciated that the scope of the invention includes other embodiments not discussed herein. Various other modifications, changes and variations which will be apparent to those skilled in the art may be made in the arrangement, operation and details of the system and method of the present invention disclosed herein without departing from the scope of the invention, which should be as in the appended claims.

, Claims:We claim:
1. An automated device (100) for dip coating and sequential ionic layer adsorption and reaction for deposition of thin films, the device (100) comprising:
a disc (102) resting on a base (104), the disc configured to hold beakers containing solutions for dipping a substrate;
a plurality of button magnets (106) on the curved surface of the disc, the button magnets inserted along the line of beaker holders (108) and configured to stop rotation of the disc at proper points of dipping the substrate;
a hall sensor switch (110) configured to detect the magnet and to identify the location of beakers;
a plurality of rods (112, 114) attached perpendicular to the base and the other end attached to a platform (116) and a substrate holder (118) attached to the platform;
a first motor (162) to rotate the disc and a second motor (164) to enable vertical movement of the substrate; and
a microcontroller (150) for automation of the device.

2. The device as claimed in claim 1, wherein the device includes an end stop switch (120) affixed to the end of the rod configured to determine the location of the substrate to be coated.

3. The device as claimed in claim 1, wherein the first motor (162) orsecond motor (164) is a bipolar stepper motor.

4. The device as claimed in claim 1, wherein one of the rods (112) is a threaded rod attached to the stepper motor to drive vertical motion of the substrate.

5. The device as claimed in claim 1, wherein the platform (116) is a mobile platform configured to support the substrate.

6. The device as claimed in claim 1, wherein the device includes a first motor driver (161) and a second motor driver (163) along with a power supply (160) to drive the motors.

7. The device as claimed in claim 1, wherein the device is configured to coat multiple substrates simultaneously.

8. The device as claimed in claim 1, wherein the disc is configured to hold beakers of varying size or number.

9. The device as claimed in claim 1, wherein the microcontroller (150) is configured to automatically drive the device to perform a pre-programmed sequence or cycles of dipping duration in each solution.

Dr V. SHANKAR
IN/PA-1733
Forand on behalf oftheApplicants