Patent Publication Number: US-11664566-B2

Title: Semiconductor device and method, where a dielectric material directly contacts a high-k dielectric material and first and second transmission lines

Description:
PRIORITY CLAIM 
     This application is a continuation of U.S. application Ser. No. 16/734,976, filed Jan. 6, 2020, now U.S. Pat. No. 11,258,151, issued Feb. 22, 2022, which is a continuation of U.S. application Ser. No. 15/696,337, filed Sep. 6, 2017, now U.S. Pat. No. 10,530,030, which is a continuation of U.S. application Ser. No. 14/748,524, filed Jun. 24, 2015, now U.S. Pat. No. 9,786,976, issued Oct. 10, 2017, which are incorporated herein by references in their entireties. 
    
    
     BACKGROUND 
     Transmission lines are used to transfer signals between portions of a circuit or system. Transmission lines are often used in radio frequency (RF) circuits. In some approaches, a pair of transmission lines called differential transmission lines are used to transfer signals between separate portions of the circuit or system. As technology nodes for circuits decrease, spacing between adjacent transmission lines decreases. 
     Unlike conductive lines in an interconnect structure, transmission lines are used to carry signals having alternating current (AC) signals. A length of transmission lines is sufficiently long that a wave nature of the transferred signal impacts performance of the transmission line. In contrast, conductive lines in interconnect structures are often formed without consideration for a wave nature of a signal along the conductive line. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. 
         FIG.  1    is a perspective view of a transmission line design according to some embodiments. 
         FIG.  2    is a perspective view of a transmission line design according to some embodiments. 
         FIGS.  3 A and  3 B  are cross-sectional views of transmission line designs according to some embodiments. 
         FIGS.  4 A- 4 C  are cross-sectional views of transmission line designs according to some embodiments. 
         FIGS.  5 A and  5 B  are cross-sectional views of transmission line designs according to some embodiments. 
         FIG.  6    is a flowchart of a method of making a transmission design according to some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. 
     Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly. 
     As spacing between adjacent transmission lines decreases, a risk for cross talk between the transmission lines increases. Differential transmission lines are used to transfer two separate signals for comparison at a receiving end of the transmission lines, so cross talk between differential transmission lines would negatively impact a precision of the signal comparison. In some approaches, an organic dielectric layer is used to separate adjacent transmission lines. However, the organic dielectric layer often does not provide sufficient isolation between the adjacent transmission lines at high frequencies of about 1 gigahertz (GHz) or more. A high-k dielectric material between adjacent transmission lines helps to increase isolation between the transmission lines in order to reduce the risk of cross talk between the transmission lines. 
     Inclusion of the high-k dielectric material between the transmission lines helps to improve impedance matching in the transmission lines. Impedance is an opposition of the transmission lines to transfer energy of signals along the transmission lines. As a frequency of the signals varies, the impedance will also vary. By increasing isolation between adjacent transmission lines, variation in the impedance due to cross talk between the transmission lines is decreased, which helps to facilitate impedance matching. Impedance matching helps to maintain precise operation of circuitry which depends on the signals from the transmission lines. Impedance matching is a greater concern as a frequency of the transferred signals increases. 
     Inclusion of the high-k dielectric material between the transmission lines also helps to control quadrature amplitude modulation (QAM). QAM is a modulation scheme used to transfer multiple signals along a same transmission line. QAM involves modulating amplitudes and/or modulating phases of signals in order to distinguish between the multiple signals along the same transmission line. 
       FIG.  1    is a perspective view of a transmission line design  100  according to some embodiments. Transmission line design  100  includes a substrate  110 , a first transmission line  120   a  and a second transmission line  120   b  over the substrate. A high-k dielectric material  130  is between first transmission line  120   a  and second transmission line  120   b . A dielectric material  140 , different from high-k dielectric material  130 , surrounds first transmission line  120   a , second transmission line  120   b  and the high-k dielectric material. 
     Substrate  110  is configured to provide mechanical support for first transmission line  120   a  and second transmission line  120   b . In some embodiments, substrate  110  includes silicon, germanium, SiGe or another suitable semiconductor material. In some embodiments, substrate  110  is a semiconductor-on-insulator substrate. In some embodiments, substrate  110  is a printed circuit board (PCB). In some embodiments, substrate  110  is also configured to support active circuitry, such as transistors. In some embodiments, substrate  110  is also configured to support conductive lines in an interconnect structure, which are separate from first transmission line  120   a  and second transmission line  120   b.    
     First transmission line  120   a  is configured to transfer at least one signal from one element in a system or circuit to another element in the system or circuit. In some embodiments, first transmission line  120   a  is configured to transfer multiple signals simultaneously. In some embodiments, the multiple signals are modulated with respect to each other. In some embodiments, first transmission line  120   a  includes copper, aluminum, tungsten, alloys thereof or other suitable conductive materials. In some embodiments, first transmission line  120   a  includes graphene or another suitable conductive element. 
     Second transmission line  120   b  is configured to transfer at least one signal from one element in the system or circuit to the other element in the system or circuit. In some embodiments, the at least one signal transferred by second transmission line  120   b  is a differential signal with respect to a signal transferred by first transmission line  120   a . In some embodiments, the at least one signal transferred by second transmission line  120   b  is not a differential signal with respect to a signal transferred by first transmission line  120   a . In some embodiments, second transmission line  120   b  is configured to transfer multiple signals simultaneously. In some embodiments, the multiple signals are modulated with respect to each other. In some embodiments, second transmission line  120   b  includes copper, aluminum, tungsten, alloys thereof or other suitable conductive materials. In some embodiments, first transmission line  120   a  includes graphene or another suitable conductive element. In some embodiments, a material of second transmission line  120   b  is a same material as the first transmission line  120   a . In some embodiments, the material of first transmission line  120   a  is different from the material of second transmission line  120   b.    
     High-k dielectric material  130  is configured to increase isolation between first transmission line  120   a  and second transmission line  120   b . By increasing isolation between first transmission line  120   a  and second transmission line  120   b , reliability of circuitry connected to the first transmission line and the second transmission line is increased due to the increased impedance matching and reduced cross talk. In some embodiments, a dielectric constant of high-k dielectric material  130  ranges from about 10 to about 20,000 at 1 GHz. If the dielectric constant is too low, then high-k dielectric material  130  does not provide sufficient isolation between first transmission line  120   a  and second transmission line  120   b , in some instances. If the dielectric constant is too high, then high-k dielectric material  130  is difficult to reliably manufacture, in some instances. In some embodiments, the dielectric constant of high-k dielectric material  130  ranges from about 7,000 to about 12,000. This narrower range provides increased isolation in comparison with lower dielectric constant values and increases ease of manufacture in comparison with other approaches, in some instances. In some embodiments, the dielectric constant of high-k dielectric material  130  is about 10,000. 
     In some embodiments, high-k dielectric material  130  includes a dielectric material such as BaTiO 3 , SiO 2 , HfO 2 , ZrO 2 , TiO 2 , La 2 O 3 , SrTiO 3 , ZrSiO 4 , HfSiO 4 , or other suitable dielectric materials. In some embodiments, high-k dielectric material  130  includes the dielectric material and a mixing agent such as resin, ink, epoxy, polyimide or another suitable mixing agent in order to increase ease of manufacture of the high-k dielectric material. 
     Transmission line design  100  includes a top surface of high-k dielectric material  130  being substantially coplanar with a top surface of first transmission line  120   a  and second transmission line  120   b . In some embodiments, high-k dielectric material  130  is formed by screen printing, photolithography, inkjet printing or another suitable formation process. 
     Dielectric material  140  is configured to provide isolation between first transmission line  120   a , second transmission line  120   b  and surrounding elements. In some embodiments, additional transmission lines are located within dielectric material  140 . In some embodiments, an interconnect structure is located within dielectric material  140 . Dielectric material  140  is different from high-k dielectric material  130 . In some embodiments, dielectric material  140  is an organic dielectric material. In some embodiments, dielectric material  140  includes an epoxy, polyimide, benzocyclobutene (BCB), polybenzoxazole (PBO) or another suitable dielectric material. Dielectric material  140  is a same thickness as corresponding dielectric materials in transmission line designs which do not include high-k dielectric material  130 . 
     In operation of transmission line design  100 , a first signal is transferred through first transmission line  120   a  and a second signal is transferred through second transmission line  120   b . A total inductance of transmission line design  100  is determined based on an inductance of first transmission line  120   a , an inductance of second transmission line  120   b , and a joint inductance between the first transmission line and the second transmission line. In situations where the first signal and the second signal are transferred in a same direction, the joint inductance is added to the inductance of first transmission line  120   a  and the inductance of second transmission line  120   b . In situations where the first signal and the second signal are transferred in opposite directions, the joint inductance is subtracted from a sum of the inductance of first transmission line  120   a  and the inductance of second transmission line  120   b . Including high-k dielectric material  130  reduces a magnitude of the joint inductance. By reducing a magnitude of the joint inductance, designing circuitry connected to first transmission line  120   a  and second transmission line  120   b  is simplified because the impedance of transmission line design  100  is less dependent on the joint inductance. 
       FIG.  2    is a perspective view of a transmission line design  200  in accordance with some embodiments. Elements in transmission line design  200  which are the same as elements in transmission line design  100  ( FIG.  1   ) have a same reference number increased by 100. In comparison with transmission line design  100  ( FIG.  1   ), transmission line design  200  includes second transmission line  220   b  on a different level with respect to first transmission line  220   a . A “different level” means that a distance between second transmission line  220   b  and substrate  210  is different from a distance between first transmission line  220   a  and the substrate. 
     High-k dielectric material  230  remains between first transmission line  220   a  and second transmission line  220   b . In contrast with high-k dielectric material  130  ( FIG.  1   ), high-k dielectric material  230  is between first transmission line  220   a  and second transmission line  220   b  in a direction perpendicular to a top surface of substrate  210 . In some embodiments, a combination of first transmission line  220   a , high-k dielectric material  230  and second transmission line  220   b  is called a transmission line stack. In some embodiments, multiple transmission line stacks are present in dielectric material  240 . 
       FIG.  3 A  is a cross-sectional view of a transmission line design  300  in accordance with some embodiments. Elements in transmission line design  300  which are the same as elements in transmission line design  100  ( FIG.  1   ) have a same reference number increased by 200. In comparison with transmission line design  100  ( FIG.  1   ), transmission line design  300  includes high-k dielectric material  330  extending over substrate  310  and over a top surface of first transmission line  320   a  and second transmission line  320   b  and covering both sidewalls of each of the first transmission line  320   a  and the second transmission line  320   b . In comparison with high-k dielectric material  130  ( FIG.  1   ), high-k dielectric material  330  helps to increase isolation between first transmission line  320   a  and surrounding elements; and between second transmission line  320   b  and surrounding elements. 
     In some embodiments which include additional transmission lines on a different level from first transmission line  320   a  and second transmission line  320   b , high-k dielectric material  330  helps to increase isolation of the first and second transmission lines from the additional transmission lines in comparison with high-k dielectric material  130  ( FIG.  1   ). In some embodiments which include an interconnect structure in dielectric material  340 , high-k dielectric material  330  helps to increase isolation of the first and second transmission lines from the interconnect structure in comparison with high-k dielectric material  130  ( FIG.  1   ). 
     In comparison with transmission line design  100  ( FIG.  1   ), transmission line design  300  has a higher production cost due to the increase in the amount of high-k dielectric material  330  relative to high-k dielectric material  130  ( FIG.  1   ). 
     In some embodiments, a top surface of high-k dielectric material  330  is substantially co-planar with a top surface of first transmission line  320   a  and second transmission line  320   b ; but high-k dielectric material  330  still surrounds sidewalls of the first and second transmission lines  320   a  and  320   b , respectively. 
       FIG.  3 B  is a cross-sectional view of a transmission line design  300 ′ in accordance with some embodiments. Elements in transmission line design  300 ′ which are the same as elements in transmission line design  100  ( FIG.  1   ) have a same reference number increased by 200. In comparison with transmission line design  300  ( FIG.  3 A ), transmission line design  300 ′ includes high-k dielectric material  330 ′ extending over a portion of a top surface of first transmission line  320   a  and second transmission line  320   b  and exposing sidewalls of each of the first transmission line and the second transmission line farthest from the adjacent transmission line. In comparison with high-k dielectric material  130  ( FIG.  1   ), high-k dielectric material  330 ′ helps to increase isolation between first transmission line  320   a  and surrounding elements; and between second transmission line  320   b  and surrounding elements. In some embodiments, high-k dielectric material  330 ′ extends over an entirety of the top surface of first transmission line  320   a  and second transmission line  320   b.    
     In some embodiments which include additional transmission lines on a different level from first transmission line  320   a  and second transmission line  320   b , high-k dielectric material  330 ′ helps to increase isolation of the first and second transmission lines from the additional transmission lines in comparison with high-k dielectric material  130  ( FIG.  1   ). In some embodiments which include an interconnect structure in dielectric material  340 , high-k dielectric material  330 ′ helps to increase isolation of the first and second transmission lines from the interconnect structure in comparison with high-k dielectric material  130  ( FIG.  1   ). 
     In comparison with transmission line design  100  ( FIG.  1   ), transmission line design  300 ′ has a higher production cost due to the increase in the amount of high-k dielectric material  330 ′ relative to high-k dielectric material  130  ( FIG.  1   ). 
       FIG.  4 A  is a cross-sectional view of a transmission line design  400  in accordance with some embodiments. Elements in transmission line design  400  which are the same as elements in transmission line design  200  ( FIG.  2   ) have a same reference number increased by 200. In comparison with transmission line design  200  ( FIG.  2   ), transmission line design  400  includes high-k dielectric material  430  extending over substrate  410  and over a top surface of first transmission line  420   a  and second transmission line  420   b  and covering both sidewalls of each of the first transmission line  420   a  and the second transmission line  420   b . In comparison with high-k dielectric material  230  ( FIG.  2   ), high-k dielectric material  430  helps to increase isolation between first transmission line  420   a  and surrounding elements; and between second transmission line  420   b  and surrounding elements. 
     In some embodiments which include additional transmission lines on a same level as at least one of first transmission line  420   a  or second transmission line  420   b , high-k dielectric material  430  helps to increase isolation of the first and second transmission lines from the additional transmission lines in comparison with high-k dielectric material  230  ( FIG.  2   ). In some embodiments which include an interconnect structure in dielectric material  440 , high-k dielectric material  430  helps to increase isolation of the first and second transmission lines from the interconnect structure in comparison with high-k dielectric material  230  ( FIG.  2   ). 
     In comparison with transmission line design  200  ( FIG.  2   ), transmission line design  400  has a higher production cost due to the increase in the amount of high-k dielectric material  430  relative to high-k dielectric material  230  ( FIG.  2   ). 
       FIG.  4 B  is a cross-sectional view of a transmission line design  400 ′ in accordance with some embodiments. Elements in transmission line design  400 ′ which are the same as elements in transmission line design  200  ( FIG.  2   ) have a same reference number increased by 200. In comparison with transmission line design  400  ( FIG.  4 A ), transmission line design  400 ′ includes high-k dielectric material  430 ′ extending over a portion of a sidewall surfaces of first transmission line  420   a  and second transmission line  420   b  and exposing the top surface of the second transmission line. In comparison with high-k dielectric material  230  ( FIG.  2   ), high-k dielectric material  430 ′ helps to increase isolation between first transmission line  420   a  and surrounding elements; and between second transmission line  420   b  and surrounding elements. In some embodiments, high-k dielectric material  430 ′ extends over less than an entirety of the sidewall surfaces of at least one of first transmission line  420   a  or second transmission line  420   b  ( FIG.  4 A ). 
     In some embodiments which include additional transmission lines on a same level as at least one of first transmission line  420   a  or second transmission line  420   b , high-k dielectric material  430 ′ helps to increase isolation of the first and second transmission lines from the additional transmission lines in comparison with high-k dielectric material  230  ( FIG.  2   ). In some embodiments which include an interconnect structure in dielectric material  440 , high-k dielectric material  430 ′ helps to increase isolation of the first and second transmission lines from the interconnect structure in comparison with high-k dielectric material  230  ( FIG.  2   ). 
     In comparison with transmission line design  200  ( FIG.  2   ), transmission line design  400 ′ has a higher production cost due to the increase in the amount of high-k dielectric material  430 ′ relative to high-k dielectric material  230  ( FIG.  2   ). 
       FIG.  4 C  is a cross-sectional view of a transmission line design  400 ″ in accordance with some embodiments. Elements in transmission line design  400 ″ which are the same as elements in transmission line design  200  ( FIG.  2   ) have a same reference number increased by 200. In comparison with transmission line design  400  ( FIG.  4 A ) and transmission line design  400 ′ ( FIG.  4 B ), transmission line design  400 ″ includes high-k dielectric material  430 ″ extending over a portion of sidewall surfaces of first transmission line  420   a  and exposed sidewalls and top surface of second transmission line  420   b . In comparison with high-k dielectric material  230  ( FIG.  2   ), high-k dielectric material  430 ″ helps to increase isolation between first transmission line  420   a  and surrounding elements; and between second transmission line  420   b  and surrounding elements. In some embodiments, high-k dielectric material  430 ″ extends over less than an entirety of the sidewall surfaces of first transmission line  420   a.    
     In some embodiments which includes additional transmission lines on a same level as at least one of first transmission line  420   a  or second transmission line  420   b , high-k dielectric material  430 ″ helps to increase isolation of the first and second transmission lines from the additional transmission lines in comparison with high-k dielectric material  230  ( FIG.  2   ). In some embodiments which includes an interconnect structure in dielectric material  440 , high-k dielectric material  430 ″ helps to increase isolation of the first and second transmission lines from the interconnect structure in comparison with high-k dielectric material  230  ( FIG.  2   ). 
     In comparison with transmission line design  200  ( FIG.  2   ), transmission line design  400 ″ has a higher production cost due to the increase in the amount of high-k dielectric material  430 ″ relative to high-k dielectric material  230  ( FIG.  2   ). 
       FIG.  5 A  is a cross-sectional view of a transmission line design  500  in accordance with some embodiments. Elements in transmission line design  500  which are the same as elements in transmission line design  100  ( FIG.  1   ) have a same reference number increased by 400. In comparison with transmission line design  100  ( FIG.  1   ), transmission line design  500  is a co-axial arrangement of first transmission line  520   a  and second transmission line  520   b . Transmission line design  500  includes high-k dielectric material  530  extending over an outer surface of first transmission line  520   a  and second transmission line  520   b  over substrate  510 . In comparison with high-k dielectric material  130  ( FIG.  1   ), high-k dielectric material  530  helps to increase isolation between first transmission line  520   a  and surrounding elements; and between second transmission line  520   b  and surrounding elements. 
     In some embodiments which include additional transmission lines on a same level or different level from as at least one of first transmission line  520   a  or second transmission line  520   b , high-k dielectric material  530  helps to increase isolation of the first transmission line  520   a  and the second transmission line  520   b  from the additional transmission lines in comparison with high-k dielectric material  130  ( FIG.  1   ). In some embodiments which include an interconnect structure in dielectric material  540 , high-k dielectric material  530  helps to increase isolation of the first transmission line  520   a  and the second transmission line  520   b  from the interconnect structure in comparison with high-k dielectric material  130  ( FIG.  1   ). 
     In comparison with transmission line design  100  ( FIG.  1   ), transmission line design  500  has a higher production cost due to the increase in the amount of high-k dielectric material  530  relative to high-k dielectric material  130  ( FIG.  1   ); and because of additional processing used to form the coaxial arrangement in transmission line design  500 . 
       FIG.  5 B  is a cross-sectional view of a transmission line design  500 ′ in accordance with some embodiments. Elements in transmission line design  500 ′ which are the same as elements in transmission line design  100  ( FIG.  1   ) have a same reference number increased by 400. In comparison with transmission line design  500  ( FIG.  5 A ), transmission line design  500 ′ includes high-k dielectric material  530 ′ extending over an outer surface of second transmission line  520   b  and exposing the outer surface of first transmission line  520   a . In comparison with high-k dielectric material  130  ( FIG.  1   ), high-k dielectric material  530 ′ helps to increase isolation between second transmission line  520   b  and surrounding elements. 
     In some embodiments, multiple coaxially arranged transmission lines are included in a transmission line design. In some embodiments, at least one coaxial arrangement includes high-k dielectric material over an outer surface of an outer-most transmission line, as in transmission line design  500  ( FIG.  5 A ) and at least one coaxial arrangement includes high-k dielectric material exposing an outer surface of an outer-most transmission line, as in transmission line design  500 ′ ( FIG.  5 B ). 
     In some embodiments, more than two transmission lines are coaxially arranged. In some embodiments, an outer surface of an outer-most transmission line is exposed by high-k dielectric material. In some embodiments, the outer surface of an outer-most transmission line is covered by high-k dielectric material. 
       FIG.  6    is a flowchart of a method  600  of forming a transmission line design in accordance with some embodiments. In operation  602 , a first transmission line is formed on a substrate. The first transmission line, e.g., first transmission line  120   a  ( FIG.  1   ), first transmission line  220   a  ( FIG.  2   ), first transmission line  320   a  ( FIGS.  3 A- 3 B ), first transmission line  420   a  ( FIG.  4 A- 4 C ), or first transmission line  520   a  ( FIGS.  5 A- 5 B ), is usable to transfer at least one signal from one element in a circuit or system to another element in the circuit or system. In some embodiments, the first transmission line is formed by plating, physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD), or another suitable formation process. In some embodiments, the first transmission line is formed in direct contact with the substrate. In some embodiments, the first transmission line is formed spaced apart from the substrate. 
     In operation  604 , a second transmission line is formed on a substrate. The second transmission line, e.g., second transmission line  120   b  ( FIG.  1   ), second transmission line  220   b  ( FIG.  2   ), second transmission line  320   b  ( FIGS.  3 A- 3 B ), second transmission line  420   b  ( FIG.  4 A- 4 C ), or second transmission line  520   b  ( FIGS.  5 A- 5 B ), is usable to transfer at least one signal from one element in a circuit or system to another element in the circuit or system. In some embodiments, the second transmission line is formed by plating, PVD, CVD, ALD, or another suitable formation process. In some embodiments, the first transmission line is formed using a same process as the process used to form the second transmission line. In some embodiments, the first transmission line is formed using a different process from the process used to form the second transmission line. 
     In some embodiments, the second transmission line is formed in direct contact with the substrate. In some embodiments, the second transmission line is formed spaced apart from the substrate. In some embodiments, the first transmission line is formed on a same level as the second transmission line. In some embodiments, the first transmission line is formed on a different level from the second transmission line. 
     In some embodiments, the first transmission line is formed simultaneously with the second transmission line. In some embodiments, the first transmission line is formed sequentially with the second transmission line. In some embodiments, a first portion of the first transmission line is formed prior to formation of the second transmission line; and a second portion of the first transmission line is formed after formation of the second transmission line. 
     In operation  606 , a high-k dielectric material is formed on the substrate. The high-k dielectric material, e.g., high-k dielectric material  130  ( FIG.  1   ), high-k dielectric material  230  ( FIG.  2   ), high-k dielectric material  330  ( FIG.  3 A ), high-k dielectric material  330 ′ ( FIG.  3 B ), high-k dielectric material  430  ( FIG.  4 A ), high-k dielectric material  430 ′ ( FIG.  4 B ), high-k dielectric material  430 ″ ( FIG.  4 C ), high-k dielectric material  530  ( FIG.  5 A ), or high-k dielectric material  530 ′ ( FIG.  5 B ), is configured to increase isolation between the first transmission line and the second transmission line. In some embodiments, the high-k dielectric material is formed using screen printing, photolithography, inkjet printing or another suitable formation process. 
     An order of operations  602 ,  604  and  606  depends on a structure of the transmission line design to be formed. In some embodiments where the first transmission line and the second transmission line are on a same level, operation  606  is performed after operations  602  and  604  are performed. In some embodiments where the first transmission line and the second transmission line are on a same level, operation  606  is performed after one of operations  602  or  604  is performed. In some embodiments where the first transmission line and the second transmission line are on different levels, operation  606  is performed prior to operation  604 . 
     In some embodiments, the high-k dielectric material is formed before at least one of the first transmission line or the second transmission line. In some embodiments, the high-k dielectric material is formed after both of the first transmission line and the second transmission line. In some embodiments, a first portion of the high-k dielectric material is formed prior to at least one of the first transmission line or the second transmission line; and a second portion of the high-k dielectric material is formed after at least one of the first transmission line or the second transmission line. 
     In operation  608 , a dielectric material is formed around the high-k dielectric material, the first transmission line, and the second transmission line. The dielectric material, e.g., dielectric material  140  ( FIG.  1   ), dielectric material  240  ( FIG.  2   ), dielectric material  340  ( FIGS.  3 A- 3 B ), dielectric material  440  ( FIGS.  4 A- 4 C ), or dielectric material  540  ( FIG.  5 A- 5 B ), is configured to provide isolation between the first transmission line and surrounding elements; and between the second transmission line and the surrounding elements. In some embodiments, the dielectric material is formed using sputtering, PVD, CVD, ALD, printing or another suitable formation process. 
     In some embodiments, the dielectric material is formed after the high-k dielectric material, the first transmission line, and the second transmission line. In some embodiments, the dielectric material is formed prior to at least one of the high-k dielectric material, the first transmission line or the second transmission line. In some embodiments, an opening is formed in the dielectric material, using etching, drilling, or another suitable process, and at least one of the first transmission line, the second transmission line or the high-k dielectric material is formed in the opening. In some embodiments where an opening is formed in the dielectric material, the dielectric material is used to fill a remaining portion of the opening following formation of the first transmission line, the second transmission line or the high-k dielectric material. In some embodiments, a first portion of the dielectric material is formed prior to at least one of the high-k dielectric material, the first transmission line or the second transmission line; and a second portion of the dielectric material is formed after at least one of the high-k dielectric material, the first transmission line or the second transmission line. 
     In some embodiments where the transmission line design has a coaxial arrangement, a first portion of the dielectric layer is formed followed by forming a recess in the dielectric layer. A first portion of the first transmission line is formed in the recess followed by a first portion of the high-k dielectric layer and then the second transmission line. In some embodiments, the second transmission line will extend above a top surface of the first portion of the dielectric layer. Following formation of the second transmission line, a second portion of the high-k dielectric layer is formed over the second transmission line to enclose the second transmission line with the first and second portions of the high-k dielectric material. A second portion of the first transmission line is then formed over the high-k dielectric material to enclose the high-k dielectric material in the first portion and the second portion of the first transmission line. 
     In some embodiments, an order of operations in method  600  is changed based on an arrangement of the high-k dielectric material, the first transmission line and the second transmission line in the transmission line design. In some embodiments, additional operations are included in method  600 , such as patterning processes, planarization process, cleaning processes, or other suitable processes. 
     An aspect of this description relates to a semiconductor device. The semiconductor device includes a first transmission line. The semiconductor device includes a second transmission line. The semiconductor device includes a high-k dielectric material between the first transmission line and the second transmission line, wherein the high-k dielectric material partially covers each of the first transmission line and the second transmission line. The semiconductor device further includes a dielectric material directly contacting the high-k dielectric material, wherein the dielectric material has a different dielectric constant from the high-k dielectric material, and the dielectric material directly contacts each of the first transmission line and the second transmission line. In some embodiments, the dielectric material directly contacts a sidewall of the high-k dielectric material and a top-most surface of the high-k dielectric material. In some embodiments, the dielectric material directly contacts the first transmission line. In some embodiments, the dielectric material directly contacts the second transmission line. In some embodiments, the semiconductor device further includes a substrate, wherein the first transmission line and the second transmission line are on the substrate, and the high-k dielectric material directly contacts the substrate. In some embodiments, the high-k dielectric material directly contacts the substrate between the first transmission line and the second transmission line. In some embodiments, the dielectric material directly contacts the substrate. 
     An aspect of this description relates to a semiconductor device. The semiconductor device includes a first transmission line. The semiconductor device further includes a second transmission line. The semiconductor device further includes a high-k dielectric material between the first transmission line and the second transmission line, wherein an entirety of the second transmission line is above the high-k dielectric material. The semiconductor device further includes a dielectric material directly contacting the high-k dielectric material, wherein the dielectric material has a different dielectric constant from the high-k dielectric material, the dielectric material directly contacts the second transmission line, and the dielectric material is separated from the first transmission line by the high-k dielectric material. In some embodiments, the dielectric material directly contacts a sidewall of the high-k dielectric material and a top-most surface of the high-k dielectric material. In some embodiments, the dielectric material directly contacts a sidewall of the second transmission line and a top-most surface of the second transmission line. In some embodiments, the semiconductor device further includes a substrate, wherein the first transmission line directly contacts the substrate, and the high-k dielectric material directly contacts the substrate. In some embodiments, the dielectric material directly contacts the substrate. 
     An aspect of this description relates to a method of making a semiconductor device. The method includes plating a first transmission line. The method further includes depositing a high-k dielectric material over the first transmission line. The method further includes plating a second transmission line over the high-k dielectric material, wherein the first transmission line is coaxial with the second transmission line. The method further includes depositing a dielectric material surrounding the first transmission line, wherein the dielectric material has a different dielectric constant from the high-k dielectric material. In some embodiments, the method further includes depositing a second high-k dielectric material over the second transmission line. In some embodiments, depositing the dielectric material includes depositing the dielectric material over the second high-k dielectric material. In some embodiments, depositing the second high-k dielectric material includes depositing the second high-k dielectric material simultaneously with depositing the high-k dielectric material. In some embodiments, depositing the second high-k dielectric material includes depositing the second high-k dielectric material coaxial with the high-k dielectric material. In some embodiments, depositing the dielectric material includes depositing the dielectric material in direct contact with a substrate. In some embodiments, depositing the dielectric material includes depositing the dielectric material in direct contact with the second transmission line. In some embodiments, plating the second transmission line includes plating the second transmission line physically separated from a substrate. 
     The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.