Patent Application
20240316727
The present disclosure relates to an apparatus and a method for the removal of one or more coatings from a panel.
The fabrication process of semiconductor and photonic devices is composed of many sequential steps to produce complete electrical and/or photonic circuits on a wafer or a panel (collectively referred to herein as a substrate) of a suitable material (e.g., semiconductor wafers, glass panels, etc.). Defects of any source introduced during the fabrication process reduces yield of the resulting devices. A common source of defects are the residues of coatings (e.g., deposited films, etc.) on the edge(s) of a substrate that the devices are formed on. These coating residues on the edge may be the result of incomplete removal of a coating used in the fabrication process from the edge. The substrate edge may be part of (or form), for example, the substrate bevel, substrate edge exclusion zone, handling area, etc. For example, portions of the residual coatings (e.g., metal films such as Ti, Cu, Pd, Ni, etc.) retained on the substrate may peel or delaminate during subsequent processing (e.g., deposition, heating, etc.) of the substrate and cause defects in the resulting device. Thus processes to satisfactorily remove the coatings from the edge(s) of a substrate used in semiconductor fabrication are important.
Currently there are limited ways to remove coatings from a substrate edge. One current method uses plasma or laser ablation where a suitable laser beam (e.g., a YAG laser) is focused on the coated substrate to ablate the coating. In addition to requiring multiple passes for satisfactory coating removal, such a removal method may also result in redeposition of debris on coated surfaces (requiring subsequent cleaning steps) and result in defects. Furthermore, laser and plasma ablation tools are expensive and may require good ventilation and other protection systems for safe use. Moreover, with substrates becoming thinner (e.g., 200-250 micron), traditional laser coating removal methods risk breaking fragile panels. Additionally, some coatings (such as, for example, copper, titanium, etc.) are difficult to remove using a laser because of the large amount of energy needed for their removal.
The apparatus and methods of the current disclosure may alleviate at least some of the above-described deficiencies. However, the scope of the current disclosure is defined by the claims and not by its ability to solve any problem.
Embodiments of an apparatus for coating removal and method of coating removal are disclosed.
In one embodiment, an apparatus to remove at least a portion of a coating from a coated surface of a substrate comprises at least one nozzle extending from a proximal end to a distal end, wherein at least a distal end portion of the at least one nozzle extends along a longitudinal axis inclined at an angle θ with the coated surface. The at least one nozzle may include an inner conduit having an orifice at the distal end and an outer conduit coaxially arranged about the inner conduit and defining an annular opening between the inner and outer conduits. The inner conduit may be configured to direct a liquid stream through the orifice to impinge on the coated surface and the outer conduit may be configured to direct a gas flow through the annular opening to surround the liquid stream from the orifice. The apparatus may also include an outlet port configured to direct liquid from the liquid stream away from the substrate after the liquid stream impinges the coated surface.
Various embodiments of the disclosed apparatus may additionally or alternatively include one of more of the following features: further include a heater configured to heat the liquid stream exiting the orifice; the apparatus may be configured to vary the angle θ between about 0-1800; the apparatus may be configured to vary a pressure of the liquid stream exiting through the orifice; the apparatus may be configured to vary a pressure of the gas exiting through the annular opening; the apparatus may be configured to translate the nozzle to trace a path using the liquid stream on the coated surface; the liquid stream may include a chemical composition that includes one or more of H2O2, H2SO4, SPS, and TBR19, and the gas flow may include air.
In another embodiment, a method of removing a coating from a coated surface of a substrate comprises positioning a nozzle of an apparatus proximate a coated surface of a substrate such that a longitudinal axis of a distal end of the nozzle is inclined at an angle θ with the coated surface. The nozzle may include an inner conduit having an orifice and an outer conduit coaxially arranged about the inner conduit and defining an annular opening between the inner and outer conduits. The method may also include directing a liquid stream through the orifice of the inner conduit toward the coated surface, and directing a gas flow through the annular opening toward the coated surface such that the gas flow surrounds the liquid stream from the orifice. The method may further include impinging the liquid stream on the coated surface to remove at least a portion of a coating of the coated surface.
Various embodiments of the disclosed method may additionally or alternatively include one of more of the following steps or features: further include directing liquid from the liquid stream away from the substrate after the liquid stream impinges on the coated surface; positioning the nozzle may include adjusting the angle θ; positioning the nozzle may include adjusting a distance of the distal end of the nozzle from the coated surface; directing the liquid stream may include adjusting a pressure of a liquid directed through the inner conduit; directing the gas flow may include adjusting a pressure of a gas directed through the outer conduit; directing the liquid stream may include directing a liquid chemical composition through the inner conduit, wherein the chemical composition may include one or more of H2O2, H2SO4, SPS, and TBR19; directing the gas flow may include directing air through the outer conduit; further include moving the nozzle to trace a path using the liquid stream on the coated surface; and directing the liquid stream may include heating a liquid in the liquid stream.
The accompanying drawings, which are incorporated herein and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, are used to explain the disclosed principles. In these drawings, where appropriate, reference numerals that illustrate the same or similar structures, components, materials, and/or elements in different figures are labeled similarly. It is understood that various combinations of the structures, components, and/or elements, other than those specifically shown, are contemplated and are within the scope of the present disclosure.
For simplicity and clarity of illustration, the figures depict the general structure of the various described embodiments. Details of well-known components or features may be omitted to avoid obscuring other features, since these omitted features are well-known to those of ordinary skill in the art. Further, features in the figures are not necessarily drawn to scale. The dimensions of some features may be exaggerated relative to other features to improve understanding of the exemplary embodiments. One skilled in the art would appreciate that the features in the figures are not necessarily drawn to scale and, unless indicated otherwise, should not be viewed as representing dimensions or proportional relationships between different features in a figure. Additionally, even if it is not expressly mentioned, aspects described with reference to one embodiment or figure may also be applicable to, and may be used with, other embodiments or figures.
All relative terms such as “about,” “substantially,” “approximately,” etc., indicate a possible variation of +10% (unless noted otherwise or another degree of variation is specified). For example, a feature disclosed as being about “t” units wide (or length, thickness, depth, etc.) may vary in width from (t−0.1t) to (t+0.1t) units. In some cases, the specification also provides context to some of the relative terms used. For example, a structure (e.g., a coating edge) described as being substantially linear may deviate by +10% from being linear. As another example, a feature (e.g., a coating edge, etc.) described as having a substantially sharp or substantially step-like configuration or shape (e.g., └-shape, ┐) may deviate by ±10% from being perfectly step-like (e.g., a shape having rounded corners, such as, for example, ,
,
,
, etc.) Further, a range described as varying from, or between, 5 to 10 (5-10), includes the endpoints (i.e., 5 and 10).
Unless otherwise defined, all terms of art, notations, and other scientific terms or terminology used herein have the same meaning as commonly understood by persons of ordinary skill in the art to which this disclosure belongs. Some components, structures, and/or processes described or referenced herein are well understood and commonly employed using conventional methodology by those skilled in the art. These components, structures, and processes will not be described in detail. All patents, applications, published applications and other publications referred to herein as being incorporated by reference are incorporated by reference in their entirety. If a definition or description set forth in this disclosure is contrary to, or otherwise inconsistent with, a definition and/or description in these references, the definition and/or description set forth in this disclosure controls over those in references incorporated by reference. None of the references described or referenced herein is admitted as prior art relative to the current disclosure.
The discussion below describes an exemplary apparatus and method used to remove a coating from an edge (or the edge zone) of a substrate (e.g., wafer, panel, etc.). It should be noted that the specific features of the described apparatus are not limitations. Instead, embodiments of the described apparatus may be used to remove any coating(s) from any substrate in any suitable application. For example, the disclosed apparatus and method may be used to remove any type of one or more coatings (organic, inorganic, metallic, etc.) from any type of substrate (e.g., panel, wafer, base plate, etc.). In the discussion below, the term “substrate” is used broadly to refer to any component having a relatively flat surface upon which a coating is disposed (conformally, as patches, in regions, etc.). For example, as used herein, a substrate includes a plate, a panel (e.g., a glass panel), a semiconductor wafer (e.g., a silicon wafer), a wafer with multiple IC devices formed thereon, a single IC device, a substrate (e.g., ceramic, organic, metallic, etc.) with one or more coatings formed or disposed thereon, etc. The “coating” on the substrate may be formed of any material (organic, inorganic, metallic, etc.), have any thickness, and may (without limitation) be disposed on the substrate by any known method (e.g., deposited, sprayed, plated, grown on, etc.).
For the sake of brevity, the use of apparatus 100 to remove the top-most coating (e.g., second coating 24) from an edge 10 of an exemplary substrate 20 in the form of a rectangular glass panel with a first coating 22 made of titanium (Ti) and a second coating 24 made of copper (Cu) will be described below. However, this configuration is only exemplary, and embodiments of the disclosed apparatus 100 may be used to remove any desired coating(s) from any type of substrate.
Apparatus 100 may be used to direct a stream or a spray of a chemical composition on a desired edge 10 of the substrate 20 through a nozzle 30.
In general, any type of a liquid chemical composition may be directed through the inner conduit 32. Typically, the type of liquid may depend on the application (e.g., the coating to be removed). For example, in some embodiments when a copper coating is to be removed from substrate 20, the chemical composition used may be based on one or more (e.g., a combination) of: H2O2/H2SO4; SPS/H2SO4; CuCl2; a combination of different proportion of any of the above chemistries. In some embodiments, when a titanium coating is to be removed, the chemical composition directed through the inner conduit 32 may be based on one or more of: H2O2/H2SO4; TechniEtch™ TBR19 concentrate (TBR 19)/H2O2; a combination of different proportion of any of the above chemistries. In some embodiments, the chemical composition may provide high selectivity to different coatings and other materials that may be present in the substrate 20 (e.g., Si, EMC, Polyimide, SiO2, etc.). For example, in an embodiment where apparatus 100 is used to remove copper film deposited over, for example, titanium film on a processed semiconductor substrate 20 (that includes materials such as polyamide, SiO2, etc.), the applied chemical composition may selectively remove copper without affecting (or with minimal effect on) the other materials.
It should be emphasized that the compositions described above are only exemplary and any liquid may be directed to the substrate 20 through the inner conduit 32. Similarly, any type of a gas (e.g., air, nitrogen, an inert gas, etc.) may be directed to the substrate 20 through the outer conduit 42. In some embodiments, the gas directed through the outer conduit 42 may be air irrespective of the type of liquid directed through the inner conduit 32. In some embodiments, the type of gas may depend on the type of liquid used. The coating (e.g., second coating 24) may be removed by the liquid chemical composition by, for example, ablation, etching, or a combination of etching and ablation. In some embodiments, the liquid chemical composition discharged through the nozzle 30 may be heated. It is also contemplated that, in some embodiments, the gas discharged through the nozzle 30 may also be heated. The apparatus 100 may include one or more heaters configured to heat the liquid and/or gas directed to the substate 20 through the nozzle 30. In some embodiments, these heaters may be coupled to the nozzle 30. In some cases, heating the liquid chemical composition (and/or the gas) may assist in coating removal.
With reference to ) of the liquid directed through the inner conduit 32, the pressure (Pg) of the gas directed through the outer conduit 42, and the angle (θ) of inclination of the longitudinal axis 90 of nozzle 30 may be adjusted such that the liquid droplets 70 that impinge on the substrate surface have a tear-drop shape. As illustrated in
It should be noted that although
With reference to and/or Pg. In some embodiments, only one of
and Pg may be varied. It is also contemplated that, in some embodiments, both
and Pg may have the same value. Although not a requirement, in some embodiments, distance (d) may be varied between about 1-50 mm or between about 10-20 mm, and one of both of
and Pg may be varied between 10-60 psi or between about 15-25 psi. The values of these parameters (e.g., θ, d,
, Pg) used may depend upon the application (type and size of substrate, type and thickness of films, etc.). In general, one or more of these parameters may be varied to produce liquid droplets of a desired shape that removes a coating in an efficient manner.
, Pg) completely removes the copper coating from the edge and produces a sharp edge 74.
When apparatus 100 is used to remove a coating (e.g., second coating 24) on substrate 20, as represented by arrow A in
In some applications, the residence (or contact) time of the liquid chemical composition (e.g., the liquid stream 50) with the coating may affect the quality of the coating removal. Residence time may be varied by controlling the speed at which the nozzle 30 and/or the substrate 20 translates to trace a path of the liquid stream 50 on the substrate surface. For example, with reference to
It should be noted that although a single nozzle 30 of apparatus 100 is described, this is not a limitation. In some embodiments, as illustrated for example in
) of the liquid directed through the inner conduit 32, and the pressure (Pg) of the gas directed through the outer conduit 42 may be varied to optimize the coating removal process. In some embodiments, substrate surface may be cleaned (e.g., using a different liquid) after step 130 (step 140). For example, in some embodiments, after step 130, a chemical composition (e.g., water, IPA, citric acid, etc.) may be directed on the surface of the substrate 20 through the nozzle 30 (e.g., through inner conduit 32) to clean (e.g., remove residues of the chemical composition used in step 130) the substrate surface. Additionally or alternatively, in some embodiments, the substrate surface may be dried (e.g., using a hot gas (e.g., air, nitrogen, etc.) after coating removal in step 130 (step 150). For example, in addition to or as an alternative to cleaning the substrate surface (i.e., step 140) after coating removal (i.e., step 130), a gas (e.g., hot air, hot nitrogen, etc.) may be directed to the substrate surface (e.g., through the outer conduit 42 of nozzle 30) to dry the substrate surface. It should be noted that steps 140 and 150 and one of both of these steps may be omitted in some embodiments. In general, the above described steps may be performed in any order (e.g., step 120 may be performed before or simultaneously with step 110, etc.). Moreover, the method may include additional steps not illustrated in
Although the current disclosure is described as being used to remove a coating from an edge (or the edge zone coating) of a substrate, this is only exemplary. For example, apparatus 100 may be used to remove a single or multiple coatings (e.g., multi-layer coatings) from any region (e.g., center, side, etc.) of a coated substrate. Persons of ordinary skill in the art would recognize that the disclosed apparatus can be used for any application (e.g., to remove paint from the surface of a component, a metallic or polymeric coating from the surface of a ceramic/organic substrate or a semiconductor wafer, etc.). Furthermore, although in the description above, some features were disclosed with reference to specific embodiments, a person skilled in the art would recognize that this is only exemplary, and the features are applicable to all disclosed embodiments. Other embodiments of the apparatus, its features and components, and related methods will be apparent to those skilled in the art from consideration of the disclosure herein.
