DESC:AN EQUIPMENT TO COUNT THE NUMBER OF WAFERS/CELLS IN A STACK OF WAFERS/CELLS

FIELD OF THE INVENTION

[001] The present disclosure, in general, relates to wafers used in solar photovoltaics and semiconductor devices. More particularly, the present invention relates to an equipment that can count the number of wafers/cells in a stack of wafers/cells and simultaneously stores and display the results on a storage module and a graphical terminal incorporated to it.

BACKGROUND OF THE INVENTION

[002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.

[003] In a crystalline silicon solar cell production line of approximately 100 MW capacity more than 50000 wafers are converted into fully functional solar cells every day. Handling of such a large number of wafers on daily basis including counting of wafers/cells at several stages manually is not a very good practice. This practice should be avoided as much as possible, as it might cause breakage of wafer/cell or may cause inadvertent touch on wafer surface. Since solar cell is a semiconductor device and hence is very sensitive to dust/dirt or oil on the finger.
[004] The raw wafers come in boxes in stacks of 100 wafers each. These boxes are then opened and the wafers are processed using different techniques to reach the final product of a fully functional solar cell. Each wafer is approximately 180 µm thick and has a cross-sectional area of almost 6 inches by 6 inches. A single wafer is very fragile and mishandling can lead to breakage of wafer thereby reducing the yield of the process. Hence, there is need for developing an equipment that does not require manual counting and handling of the wafers/cells in a stack.

PRIOR ART OF THE INVENTION

[005] There are some apparatus and methods known to the art regarding use of a semi-conductor wafers. These are discussed herein below:

[006] US20030202178A1, titled “Semiconductor wafer inspection apparatus” describes an apparatus provided with a rotatable table on which a semiconductor wafer is sucked and held, a semiconductor wafer held on the rotatable table, an imaging device which captures an image of the edge portion of the semiconductor wafer when the edge portion is illuminated by the illuminating device, an image processing device which detects at least an edge cut amount or a crack by acquiring the image of the edge portion which is captured by the imaging device, and a display section which displays an image of the edge portion subjected to image processing by the image processing device.

[007] US6791680B1 titled “System and method for inspecting semiconductor wafers” discloses a method for inspecting semiconductor wafers in which a plurality of independent, low-cost, optical inspection subsystems are packaged and integrated to simultaneously perform parallel inspections of portions of the wafer, the wafer location relative to the inspection being controlled so that the entire wafer is imaged by the system of optical subsystems in a raster-scan mode. A monochromatic coherent-light source illuminates the wafer surface. A dark field-optical system collects scattered light and filters patterns produced by valid periodic wafer structures using Fourier filtered. The filtered light is processed by general purpose digital-signal processors. Image subtraction methods are used to detect wafer defects, which are reported to a main controller to aid in statistical process control, particularly for manufacturing equipment.

[008] The above mentioned prior arts are related to apparatus and method for analyzing and inspecting defects in edges of the semiconductor wafers. However, it is evident from the prior art that there is no such equipment developed that can count the number of wafers/cells in a stack of wafers/cells. In pursuit of this, the present invention focuses on development of an equipment that can count the number of wafers or cells in the stack of wafers or cells up to a maximum of 100 wafers.

OBJECTIVE OF THE INVENTION

[009] It is an object of the present subject matter to overcome the aforementioned and other drawbacks existing in the prior art systems and methods.

[010] It is the principle object of the present subject matter to provide an equipment that can count the number of wafers in a stack of wafers up to a maximum of 100 wafers.

[011] It is another object of the present subject matter to provide the equipment to count the number of wafers in the stack of wafers having no size limit for wafer.

[012] It is still another object of the present subject matter to provide the equipment to enhance the yield and efficiency of both solar cell and production line.

[013] It is yet another object of the present subject matter to provide the equipment to count the number of wafers in the stack of wafers and simultaneously display the results on a graphical terminal incorporated with the equipment.

[014] These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.

SUMMARY OF THE INVENTION

[015] The present invention relates to, developing of an equipment, which is highly required in a solar cell manufacturing company where more than 50000 wafers are handled every day having a solar cell manufacturing unit of 85 MW or more. These wafers come in boxes where a single box contains 100 wafers each and after complete processing are converted into fully functional solar cells. The equipment counts the number of wafers in a stack of wafers and the results are displayed on a display unit. Moreover, a storage module is provided which stores the number of count of wafers, date and time of the previous stack.

[016] According to an embodiment of the present invention, there is provided an equipment to enhance yield and efficiency of solar cell production line, the equipment comprises of a crate which is for holding the stack of wafers, a microscope, a magnification camera and an image analyzing module which is configured for scrutinizing of enhanced image. Herein, the equipment is incorporated with a storage module having a memory unit that stores data and a graphical terminal having a display screen for visualizing data.

[017] In an aspect, the equipment can count up to maximum of 100 wafers.

[018] In an aspect, in the equipment, thickness of each wafer is 180 µm and the cross-sectional area is 6*6 inches.

[019] In an aspect, in the equipment, the microscope can be used to provide high-resolution and high-contrast image of the edges of wafer.

[020] In an aspect, in the equipment, the microscope can be used to identify gap filled with air between two wafers.

[021] In an aspect, there is further provided a method of counting number of wafers in a given stack of wafer using an equipment, the method comprises, placing a crate containing the stack of wafers in the equipment, directing a laser beam through a microscope to the edges of stack of wafers, recording of reflected laser beam using a magnification camera and an image analyzing module, generating enhanced image using a magnification camera, analyzing enhanced image through the image analyzing module and simultaneously storing data in a storage module and receiving output on a graphical terminal.

[022] To further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit the scope of the present subject matter.

[023] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING(S)

[024] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description outlines with reference to the accompanying figures. In the figures, a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods or structure in accordance with embodiments of the present subject matter is now described, by way of example, and with reference to the accompanying figures, in which

[025] Figure 1 illustrates an exemplary block diagram of an equipment, incorporated with a storage module and a graphical terminal in accordance with an embodiment of the present disclosure; and

[026] Figure 2 illustrates a flowchart depicting an exemplary operation of the equipment, incorporated with a storage module and a graphical terminal in accordance with an exemplary embodiment of the present disclosure.

[027] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION OF INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS OF THE PREFERRED EMBODIMENT(S)

[028] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to panel all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.

[029] While the embodiments of the disclosure are subject to various modifications and alternative forms, specific embodiment thereof have been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to panel all modifications, equivalents, and alternative falling within the scope of the disclosure.

[030] The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to panel a non-exclusive inclusion, such that a device, system, assembly that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system, or assembly, or device. In other words, one or more elements in a system or device proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or device.

Non- limiting Definition:

[031] A photovoltaic cell, commonly known as a solar cell, is a non-mechanical device that converts solar energy directly into electrical energy. Some photovoltaic cell can convert artificial light into electricity. The photovoltaic cell can be manufactured in a variety of ways and from many different materials. The most common material for commercial solar cell construction is Silicon (Si), but others include Gallium Arsenide (GaAs), Cadmium Telluride (CdTe) and Copper Indium Gallium Selenide (CIGS).

[032] There are various types of wafers that can be used to make the solar cells or the photovoltaic cells. A solar wafer or silicon wafer is a thin slice of a crystalline silicon or a semiconductor, which works as a substrate for microeconomic devices for fabricating integrated circuits in photovoltaic to manufacture solar cells. The solar wafer is vital to photovoltaic production as well as to the power generation system of photovoltaic.

[033] In accordance with the present subject matter of the invention, an equipment (102) is provided that can count the number of wafers/cells in a stack of wafers/cells. Here, wafers are packed in boxes containing 100 wafers each of which is counted through the equipment (102). The results are displayed on a graphical terminal (122) and a storage module (112) can save all the previous stack counts with date and time in a suitable folder.

[034] Figure 1 refers to an exemplary block diagram of the equipment (102) incorporated with the storage module (112) and the graphical terminal (122).

[035] In an aspect, the equipment (102) is configured with a crate (104) which is for holding the stacks of wafers, a microscope (106), a magnification camera (108) which is for high magnification of image, and an image analyzing module (110).

[036] In a preferred embodiment, the crate (104) can hold 100 number of wafers at a time. The thickness of each wafer is 178 to 182 µm, preferably 180 µm and the surface area of each wafer may range from 6*6 to 12*12 inches, preferably 6*6 inches.

[037] In a preferred embodiment, the microscope (106) can be a laser microscope. The microscope (106) is used to obtain high-resolution and high-contrast image of the edges of wafer.

[038] In a preferred embodiment, the image analyzing module (110) is for scrutinizing of enhanced image and thus accurately provides the number of wafers in the stack.

[039] In an aspect, the storage module (112) and the graphical terminal (122) is connected at the output end of the equipment (102).

[040] In a preferred embodiment, the storage module (112) is configured with a memory unit (114) which is for storing the information of wafers such as, number of count, date and time.

[041] In a preferred embodiment, the graphical terminal (122) is configured with a display screen (124) which displays the data of wafer.

Working of the invention
[042] The working of the equipment (102) is illustrated with reference to Figure 2.

[043] Figure 2 illustrates an exemplary method (200) implemented to operate the system (100) proposed in the present disclosure. The order in which the method (200) is described is not intended to be construed as a limitation, and any number of the described method blocks may be combined in any order to implement the method (200), or an alternative method.

[044] At block (202), the method includes, placing of the crate (104) containing the stack of wafers in the equipment (102).

[045] At block (204), the method includes, directing of a laser beam to the edge of the stack of wafers.

[046] At block (206), the method includes, recording of the reflected laser beam using the magnification camera (108) and the image analyzing module (110).

[047] At block (208), the method includes, generating enhanced image using the magnification camera (108).

[048] At block (210), the method includes, analyzing enhanced image using the image analyzing module (110).
[049] In an aspect, the image analyzing module (110) can identify air filled gap between the two wafers. This air filled gap is very small.

[050] At block (212), the method includes, simultaneously storing data in the storage module (112) and receiving of output on the graphical terminal (122).
[051] In an aspect, the memory unit (114) stores the data and the display screen (124) displays the number of wafer count with date and time.

Advantages of the invention

[052] The equipment (102) described in the present disclosure is having the following advantages:
a) The fundamental advantage of the equipment (102) is to enhance the yield and efficiency of the photovoltaic cell production line.
b) The proposed equipment (102) reduces human contact and time consumed in the process.
c) The proposed equipment (102) is cost effective.
It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various systems that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.

Although embodiments for the present subject matter have been described in language specific to package features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/device of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to panel all such modifications and adaptations which fall within the scope of the present subject matter.

It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.).

In those instances, where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”

It will be further appreciated that functions or structures of a plurality of components or steps may be combined into a single component or step, or the functions or structures of one-step or component may be split among plural steps or components. The present invention contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention. The present invention also encompasses intermediate and end products resulting from the practice of the methods herein. The use of “comprising” or “including” also contemplates embodiments that “consist essentially of” or “consist of” the recited feature.

,CLAIMS:
We Claim:
1. An equipment (102) to count the number of wafers/cells in a stack of wafers/cells which enhances yield and efficiency of solar cell production line, the equipment (102) comprises:
? a crate (104) for holding the stack of wafers;
? a microscope (106);
? a magnification camera (108); and
? an image analyzing module (110) which is configured for scrutinizing of enhanced image;
wherein the equipment (102) is incorporated with a storage module (112) having a memory unit (114) that stores data and a graphical terminal (122) having a display screen (124) for visualizing data.

2. The equipment (102) as claimed in claim 1, wherein the equipment (102) counts up to maximum of 100 wafers.

3. The equipment (102) as claimed in claim 1or 2, wherein thickness of each wafer ranges from 178 µm to 182 µm and the cross-sectional area ranges from 6*6 inches to 12*12 inches.

4. The equipment (102) as claimed in claims 1-3, wherein the microscope (106) is used to provide high-resolution and high-contrast image of the edges of wafer.

5. The equipment (102) as claimed in claims 1-4, wherein the microscope (106) is used to identify gap filled with air between two wafers.

6. A method (200) of counting number of wafers in a given stack of wafer using an equipment (102) as claimed in claim 1, the method (200) comprising steps of:
? placing a crate (104) containing the stack of wafers in the equipment (102);
? directing a laser beam through a microscope (106) to the edges of stack of wafers;
? recording of reflected laser beam using a magnification camera (108) and an image analyzing module (110);
? generating enhanced image using a magnification camera (108);
? analyzing enhanced image through the image analyzing module (110); and
? simultaneously storing data in a storage module (112) and receiving output on a graphical terminal (122).

Dated this 12th day of July, 2021

SOMA RANI MISHRA
PATENT AGENT
IN/PA – 1159
OF L. S. DAVAR & CO.,
APPLICANT’S AGENT