Patent Application
20230110307
The present disclosure relates to electrical interconnections for multi-layer heater constructions.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Typical multi-layer heater constructions (e.g., ceramic pedestals) may include electrical interconnections between at least two electrically active layers. For example, one or more electrical interconnections may be employed between a heating layer and a subsequent routing layer, which are physically separated through an electrically insulating layer (i.e., dielectric layer). In other examples, a multi-layer heater construction may include several heating layers and several routing layers with electrical interconnections extending between layers and electrical interconnections extending up to the top of the heater assembly, where they may or may not act as a terminal for further electrical connection of the heater.
Challenges associated with electrical interconnections/vias include manufacturing an electrical interconnection/via by means of a conventional tape masking procedure. Such a tape mask typically results in a cylindrical via geometry with sharp outside edges and vertical faces, which pose a challenge during a subsequent coating procedure of a routing layer. Consequently, uniform layer properties are difficult to obtain along such edges and faces. The via could be filled with a conductive material prior to the coating of the routing layer instead, however, additional manufacturing steps would be used, which would complicate the manufacturing process. These challenges, among other challenges in the construction of multi-layer heaters, such as ceramic pedestals in semiconductor processing, are addressed by the present disclosure.
This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features.
In one form, the present disclosure provides an electrical interconnect for use in connecting layers of a multi-layer heater. The electrical interconnect comprises a shaped body having a lower end portion and an upper end portion. The lower end portion has a smaller contact area than a contact area of the upper end portion, and the contact area of the lower end portion is proximate a heating layer and the contact area of the upper end portion is proximate a routing layer.
In variations of the electrical interconnect, which may be implemented individually or in any combination: the shaped body defines a varying circular cross-sectional area; the shaped body comprises a concave radius extending around a periphery and adjacent to the lower end portion of the shaped body; the shaped body comprises a convex radius extending around a periphery and adjacent to the upper end portion of the shaped body; the shaped body defines a sidewall extending at an angle up to about 45 degrees between the lower end portion and the upper end portion; and the shaped body comprises a plurality of individual segments.
In another form, the present disclosure provides a multi-layer heater that comprises a heating layer, a dielectric layer, a routing layer, and at least one via. The dielectric layer is disposed over the heating layer. The routing layer is disposed over the dielectric layer. The via extends from the heating layer, through the dielectric layer, and to the routing layer, thereby forming an electrical interconnect. The via includes a shaped body having a lower end portion and an upper end portion. The lower end portion has a smaller contact area than a contact area of the upper end portion, and the contact area of the lower end portion is proximate the heating layer and the contact area of the upper end portion is proximate the routing layer.
In variations of the multi-layer heater, which may be implemented individually or in any combination: the heating layer comprises a plurality of resistive traces and at least one resistive trace extends near the lower end portion and under the upper end portion of the via; the shaped body defines a varying circular cross-sectional area; the shaped body comprises a concave radius extending around a periphery of the shaped body and adjacent to the lower end portion; the shaped body comprises a convex radius extending around a periphery of the shaped body and adjacent to the upper end portion; the shaped body comprises a plurality of individual segments; the via defines a sidewall extending at an angle up to about 45 degrees through the dielectric layer; and the via extends at least partially into the heating layer.
In yet another form, the present disclosure provides a multi-layer heater that comprises a heating layer, a dielectric layer, and a routing layer. The dielectric layer is disposed over the heating layer and comprises at least one aperture exposing the heating layer. The routing layer is disposed over the dielectric layer and extends into the aperture and onto the heating layer. The aperture is shaped to have a lower end portion and an upper end portion. The lower end portion has a smaller opening than an opening of the upper end portion, and the opening of the lower end portion is proximate the heating layer and the opening of the upper end portion is proximate the routing layer.
In some variations of the multi-layer heater of the above paragraph, a protective layer is formed over the routing layer.
In still yet another form, the present disclosures process of forming a multi-layer heater. The process comprising forming a heating layer; forming a dielectric layer over the heating layer, the dielectric layer comprising at least one aperture exposing the heating layer; and forming a routing layer over the dielectric layer, the routing layer extending into the aperture and onto the exposed heating layer. The aperture is shaped to have a lower end portion and an upper end portion. The lower end portion has a smaller opening than an opening of the upper end portion, and the opening of the lower end portion is proximate the heating layer and the opening of the upper end portion is proximate the routing layer.
In variations of forming the multi-layer heater, which may be implemented individually or in any combination: the aperture is formed by using a mask when forming the dielectric layer; the aperture is formed by removing areas of the dielectric layer with a subtractive process; at least a portion of the heating layer is removed by a subtractive process; the subtractive process is selected from the group consisting of laser ablation, mechanical milling, chemical etching, waterjet, and combinations thereof; the aperture is formed by first depositing and curing a maskant onto the heating layer, applying the dielectric layer over the maskant and the heating layer, removing the maskant, and subsequently removing portions of the dielectric layer to shape the aperture; forming a protective layer over the routing layer; and planarizing an upper surface of the protective layer.
In still yet another form, the present disclosures process of forming a multi-layer heater. The process comprising forming a heating layer; forming a dielectric layer over the heating layer, the dielectric layer comprising at least one aperture exposing the heating layer; forming a via within the at least one aperture, the via being in contact with the heating layer; and forming a routing layer over the dielectric layer, the routing layer being in contact with the via. The aperture is shaped to have a lower end portion and an upper end portion. The lower end portion has a smaller opening than an opening of the upper end portion, and the opening of the lower end portion is proximate the heating layer and the opening of the upper end portion is proximate the routing layer.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
Referring to
Referring to
The dielectric layer 34 is disposed on the resistive layer 32 and between the resistive layer 32 and the routing layer 36. The dielectric layer 34 insulates the resistive layer 32 and the routing layer 36, and in one form includes at least one aperture 38 exposing the resistive layer 32. As shown, the aperture 38 is shaped to define a varying circular cross-sectional area. However, it should be understood that the cross-sectional may be another suitable shape besides circular (such as by way of example, elliptical or polygonal) and should not be limited to a circular cross-section as illustrated herein. The aperture 38 is shaped to have a lower end portion 40 and an upper end portion 42. The lower end portion 40 has an opening 44 that is smaller than an opening 46 of the upper end portion 42. The opening 44 of the lower end portion 40 is proximate the resistive layer 32 and the opening 46 of the upper end portion 42 is proximate the routing layer 36. The aperture 38 also defines a sidewall 48 extending at an angle α between the lower end portion 40 and the upper end portion 42. In one form the angle α is equal to or less than 45 degrees. As further shown in this form, the sidewall 48 increases in slope towards the center of the aperture 38 down to the resistive layer 32. The aperture 38 also has a smooth outside edge 50 in this form.
The routing layer 36 is disposed on the dielectric layer 34 and extends into the aperture 38 (i.e., disposed on the sidewall 48 of the aperture 38) and onto the exposed resistive layer 32. The routing layer 36 is disposed on the exposed resistive layer 32 in a central area of the aperture 38, thereby forming an electrical connection by a planar contact between the routing layer 36 and the resistive layer 32. In this way, the routing layer 36 electrically connected to one or more of the cables 26 supplies power to one or more zones of the resistive layer 32. In this form, the resistive layer 32 is continuous in the area where the electrical connection is formed (i.e., in the area where there is a planar contact between the routing layer 36 and the resistive layer 32). In some examples, as shown in
Referring to
The dielectric layer 134 is disposed on the resistive layer 132 and between the resistive layer 132 and the routing layer 136. The dielectric layer 134 generally insulates the resistive layer 132 and the routing layer 136, and in one form includes at least one aperture 138 exposing the resistive layer 132 and the ceramic substrate 130. The aperture 138 is shaped to have a lower end portion 140 and an upper end portion 142. The lower end portion 140 has an opening 144 that is smaller than an opening 146 of the upper end portion 142. The opening 144 of the lower end portion 140 is proximate the resistive layer 132 and the opening 146 of the upper end portion 142 is proximate the routing layer 136. The aperture 138 also defines a sidewall 148 having a first portion 148a and a second portion 148b. The first portion 148a has a linear surface and is positioned proximate the routing layer 136. The first portion 148a also extends at an angle α between the lower end portion 140 and the upper end portion 142. The angle α may be equal to or less than 45 degrees. The second portion 148b has a non-linear surface and is positioned proximate the resistive layer 132. In the example provided, the second portion 148b has an elliptical shape, however, in some forms, the second portion 148b may be another suitable shape (e.g., a spherical shape).
The routing layer 136 is disposed on the dielectric layer 134 and extends into the aperture 138 (i.e., disposed on the first and second portions 148a, 148b of the sidewall 148). In some configurations, as shown in
Referring to
The second dielectric layer 237 is disposed on the routing layer 236 and electrically and mechanically insulates the routing layer 236 from external influences. In one form, the second dielectric layer 237 is planarized using a subtractive process such as by way of example laser ablation, mechanical milling, chemical etching, waterjet, and combinations thereof, among others. In this way, an even surface is provided for the subsequent assembly of a multi-layer heater engine.
Referring to
Next, at 306, a dielectric layer is formed over the resistive layer. The dielectric layer includes at least one aperture exposing the resistive layer. In one form, the aperture is formed by using a mask when forming the dielectric layer. In another form, the aperture is formed by removing areas of the dielectric layer with a substrative process. The substrative process is selected from the group consisting of laser ablation, mechanical milling, chemical etching, waterjet, and combinations therefor. In this way, the aperture is shaped to have a lower end portion, an upper end portion, and a sidewall extending at an angle between the lower end portion and the upper end portion. The lower end portion has an opening that is smaller than an opening of the upper end portion. The angle may be equal to or less than 45 degrees.
Lastly, at 310, a routing layer is formed over the dielectric layer and extends into the aperture (i.e., disposed on the sidewall of the aperture) and onto the exposed resistive layer. The routing layer may be formed using thermal spray deposition, for example, such that an electrical interconnection with a defined thickness is formed from the routing layer down to the resistive layer.
The method 300 is just one example of forming the ceramic pedestal assembly of the present disclosure and may include other or alternate steps. For example, in another form, the method 300 further includes removing at least a portion of the resistive layer by a substrative process (
In yet another form, the method 300 includes forming the aperture by first depositing and curing a liquid maskant onto the resistive layer, applying the dielectric layer over the maskant and the resistive layer, removing the maskant, and subsequently removing portions of the dielectric layer using a subtractive process to shape the aperture. The liquid maskant may be a UV (ultraviolet) curable maskant, for example.
In still another form, the method 300 may include forming a protective layer over the routing layer and planarizing an upper surface of the protective layer (
Referring to
The dielectric layer (not shown) is disposed on the resistive layer 432 and between the resistive layer 432 and the routing layer. The dielectric layer generally insulates the resistive layer 432 and the routing layer, and in one form includes at least one aperture (not shown) exposing the resistive layer. The aperture is shaped to define a varying circular cross-sectional area. However, it should be understood that the cross-sectional may be another suitable shape as set forth above and should not be limited to a circular cross-section. The structure of the aperture may be similar or identical to the apertures 38, 138 described above, and therefore, will not be described again in detail. The routing layer is disposed on the dielectric layer and in contact with the vias 438.
With additional reference to
In some forms, as shown in
Referring to
The via 538 includes a shaped body 544 having a lower end portion 546 and an upper end portion 548. The lower end portion 546 has a smaller contact area than a contact area of the upper end portion 548. The contact area of the lower end portion 546 is proximate a heating layer and the contact area of the upper end portion 548 is proximate a routing layer. The shaped body 544 of the via 538 also includes a plurality of individual segments 550 that are spaced apart from each other. It is understood that although 3 segments are shown, the via 538 may include more or less individual segments 550. The spaces between the segments 550 are filled with an electrically conductive material, and thus the segmentation provides improved adhesion of subsequent layers. The via 538 also includes a certain redundancy in case one of the segments defaults then the other remaining segments can take over the current load.
Referring to
Next, at 606, a dielectric layer is formed over the resistive layer. The dielectric layer includes at least one aperture exposing the resistive layer. In one form, the aperture is formed by using a mask when forming the dielectric layer. In another form, the aperture is formed by removing areas of the dielectric layer with a substrative process. The substrative process is selected from the group consisting of laser ablation, mechanical milling, chemical etching, waterjet, and combinations therefor. In this way, the aperture is shaped to have a lower end portion, an upper end portion, and a sidewall extending at an angle between the lower end portion and the upper end portion. The lower end portion has an opening that is smaller than an opening of the upper end portion. The angle may be equal to or less than 45 degrees.
Next, at 610, a via is formed within the at least one aperture of the dielectric layer. The via is in contact with the resistive layer and may have a shape that corresponds to the aperture of the dielectric layer.
Lastly, at 614, a routing layer is formed over the dielectric layer and is in contact with the via, thereby forming an electrical interconnect. The routing layer may be formed using thermal spray deposition, for example.
It should be understood that the ceramic pedestal assembly is not limited by the specific multi-layered structure and the pedestal assembly may further comprise additional functional layers (e.g., bonding layer, dielectric layers, sensing layer, and protective layer, among others) while still remaining within the scope of the present disclosure. In one example, the pedestal assembly further comprises additional heating layers and routing layers with interconnections buried in between layers and interconnections reaching up to the top of the heater configuration where the interconnections may or may not act as a terminal for further electrical contacting of the heater construction (e.g., through hole or blind via with or without electrically interfacing to external components).
The ceramic pedestal assembly of the present disclosure provides the benefit of an electrical interconnect having a shape that improves the heaters thermal signature. The present disclosure also provides the benefit of improving the manufacturing process of the ceramic pedestal assembly (e.g., reducing manufacturing steps while allowing the manufacturing process to be semi or fully automated). The ceramic pedestal assembly of the present disclosure also provides the benefit of an electrical interconnect with smooth outside edges, which provides high operating reliability especially when depositing the routing layer using thermal spray deposition.
Unless otherwise expressly indicated herein, all numerical values indicating mechanical/thermal properties, compositional percentages, dimensions and/or tolerances, or other characteristics are to be understood as modified by the word “about” or “approximately” in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice, material, manufacturing, and assembly tolerances, and testing capability.
As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”
The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.
