Embodiments of the present disclosure generally relate to a methods and apparatus for processing a substrate, and more particularly, to methods and apparatus configured for low-temperature thin film transistor as active device on polymer substrate.
In today's semiconductor backend packaging applications, substrates can include multiple die inside the same semiconductor package, e.g., in applications where high performance and low power are critical. For example, high performance and/or low power are, typically, required for communication between one or more integrated circuit (IC) chips disposed on substrates—which can be established using either a silicon (Si) or one or more polymers as an interposer (redistribution layer (RDL) or substrate). For example, the polymer interposer (e.g., for 2.1D or 3D systems in package integration) is traditionally passive interconnects (e.g., copper) that are integrated using a Si substrate, e.g., a chip or layer with through-silicon vias (TSV) for communication. Such devices, however, require signals to pass through a lossy Si substrate/TSV and consume expensive logic real estate on the substrate.
Accordingly, the inventors have provided methods and apparatus configured for low-temperature thin film transistor as active device on polymer substrate.
Methods and apparatus for processing a substrate are provided herein. In some embodiments, a method for processing a substrate includes depositing a first metal layer on a substrate and etching the first metal layer to form a gate electrode, depositing a dielectric layer atop the gate electrode, depositing a semi-conductive oxide layer atop the dielectric layer to cover a portion of the gate electrode, etching the dielectric layer from a portion of the gate electrode that is not covered by the semi-conductive oxide layer to form a gate access via, and depositing a second metal layer atop the dielectric layer and the semi-conductive oxide layer, and within the gate access via.
In accordance with at least some embodiments, a non-transitory computer readable storage medium having stored thereon instructions that when executed by a processor performs a method of processing a substrate. The method includes depositing a first metal layer on a substrate and etching the first metal layer to form a gate electrode, depositing a dielectric layer atop the gate electrode, depositing a semi-conductive oxide layer atop the dielectric layer to cover a portion of the gate electrode, etching the dielectric layer from a portion of the gate electrode that is not covered by the semi-conductive oxide layer to form a gate access via, and depositing a second metal layer atop the dielectric layer and the semi-conductive oxide layer, and within the gate access via.
In accordance with at least some embodiments, an apparatus for use with a thin film transistor includes a first metal layer deposited on a carrier substrate and having a gate electrode formed thereon, a dielectric layer deposited atop the gate electrode, a semi-conductive oxide layer deposited atop the dielectric layer to cover a portion of the gate electrode, a gate access formed in a portion of the gate electrode that is not covered by the semi-conductive oxide layer, and a second metal layer is deposited atop the dielectric layer and the semi-conductive oxide layer, and within the gate access via.
Other and further embodiments of the present disclosure are described below.
Embodiments of the present disclosure, briefly summarized above and discussed in greater detail below, can be understood by reference to the illustrative embodiments of the disclosure depicted in the appended drawings. However, the appended drawings illustrate only typical embodiments of the disclosure and are therefore not to be considered limiting of scope, for the disclosure may admit to other equally effective embodiments.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. The figures are not drawn to scale and may be simplified for clarity. Elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.
Embodiments of a methods and apparatus for processing a substrate are provided herein. For example, methods can include embedding a thin film transistor (TFT) within a matrix of polymer RDL interposer, e.g., for fan-out wafer-level packaging, embedded packaging in substrate technology, etc. The TFT can be embedded onto one or more layers (e.g., first layer, second layer, third layer, etc.) of the RDL interposer. In at least some embodiments, the TFT can be embedded on a first metal layer of the RDL. The TFT gate can be formed where gate metal is placed at the bottom layer, top or dual-gates (top & bottom). The TFT can be formed using one or more suitable metal oxides (e.g., zinc oxide, aluminum doped zinc oxide, indium-zinc oxide, indium-gallium-zinc-oxide (IGZO), etc.) to form an active channel. Embedding the TFT within a matrix of polymer or RDL interposer provides signal buffering having a shorter path, e.g., without a need for Si substrate/TSV, thus enabling better performance and lower system integration costs, when compared to conventional interposers for fan-out wafer-level packaging, embedded packaging in substrate technology, etc.
The method 100 may be performed in the tool 200 including any suitable process chambers configured for one or more of physical vapor deposition (PVD), chemical vapor deposition (CVD), such as plasma-enhanced CVD (PECVD) and/or atomic layer deposition (ALD), such as plasma-enhanced ALD (PEALD) or thermal ALD (e.g., no plasma formation). Exemplary processing systems that may be used to perform the inventive methods disclosed herein are commercially available from Applied Materials, Inc., of Santa Clara, Calif. Other process chambers, including those from other manufacturers, may also be suitably used in connection with the teachings provided herein.
The tool 200 can be embodied in individual process chambers that may be provided in a standalone configuration or as part of a cluster tool, for example, an integrated described below with respect to
The integrated tool includes a processing platform 201 (vacuum-tight processing platform), a factory interface 204, and a system controller 202. The processing platform 201 comprises multiple process chambers, such as 214A, 214B, 214C, and 214D operatively coupled to a transfer chamber 203 (vacuum substrate transfer chamber). The factory interface 204 is operatively coupled to the transfer chamber 203 by one or more load lock chambers (two load lock chambers, such as 206A and 206B shown in
In some embodiments, the factory interface 204 comprises a docking station 207, a factory interface robot 238 to facilitate the transfer of one or more semiconductor substrates (wafers). The docking station 207 is configured to accept one or more front opening unified pod (FOUP). Four FOUPS, such as 205A, 205B, 205C, and 205D are shown in the embodiment of
In some embodiments, the process chambers 214A, 214B, 214C, and 214D, are coupled to the transfer chamber 203. The process chambers 214A, 214B, 214C, and 214D comprise at least an ALD chamber, a CVD chamber, a PVD chamber, an e-beam deposition chamber, an electroplating, electroless (EEP) deposition chamber, a wet etch chamber, a dry etch chamber, an anneal chamber, and/or other chamber suitable for performing the methods described herein.
In some embodiments, one or more optional service chambers (shown as 216A and 216B) may be coupled to the transfer chamber 203. The service chambers 216A and 216B may be configured to perform other substrate processes, such as degassing, bonding, chemical mechanical polishing (CMP), wafer cleaving, etching, plasma dicing, orientation, substrate metrology, cool down and the like.
The system controller 202 controls the operation of the tool 200 using a direct control of the process chambers 214A, 214B, 214C, and 214D or alternatively, by controlling the computers (or controllers) associated with the process chambers 214A, 214B, 214C, and 214D and the tool 200. In operation, the system controller 202 enables data collection and feedback from the respective chambers and systems to optimize performance of the tool 200. The system controller 202 generally includes a central processing unit (CPU) 230, a memory 234, and a support circuit 232. The CPU 230 may be any form of a general-purpose computer processor that can be used in an industrial setting. The support circuit 232 is conventionally coupled to the CPU 230 and may comprise a cache, clock circuits, input/output subsystems, power supplies, and the like. Software routines, such as processing methods as described above may be stored in the memory 234 (e.g., non-transitory computer readable storage medium having instructions stored thereon) and, when executed by the CPU 230, transform the CPU 230 into a system controller 202 (specific purpose computer). The software routines may also be stored and/or executed by a second controller (not shown) that is located remotely from the tool 200.
Continuing with reference to
As noted above, the method 100 can be used for forming the TFT gate where gate metal is placed at a bottom layer, a top layer, or dual-gates (top and bottom layers). For illustrative purposes, the method 100 is described in terms of the TFT being embedded on a first layer (e.g., a bottom layer—bottom gated) of the RDL interposer. In embodiments where the TFT is embedded in a last layer (e.g., a top layer—top gated), the method 100 would use a reverse sequence of operations, and dual gated is combination of both top gated and bottom gated, which can provide better gate control.
Initially, the substrate 300 may be loaded into one or more of the Four FOUPS, such as 205A, 205B, 205C, and 205D. For example, in at least some embodiments, the substrate 300 can be loaded into FOUP 205A.
The method 100 includes, at 102, depositing a first metal layer 302 on the substrate 300 and etching the first metal layer to form one or more gate electrodes. For example, once loaded, the factory interface robot 238 can transfer the substrate 300 from the factory interface 204 to the processing platform 201 through, for example, the load lock chamber 206A. The vacuum robot 242 can transfer the substrate 300 from the load lock chamber 206A to and from one or more of the process chambers 214A-214D and/or the service chambers 216A and 216B. For example, the vacuum robot 242 can transfer the substrate 300 to the process chamber 214A to deposit the first metal layer 302 using one or more of the above-mentioned deposition processes. In at least some embodiments, the process chamber 214A can be configured to perform PVD (e.g., DC sputtering) to deposit the first metal layer, which can be at least one of titanium, copper, or molybdenum, or other suitable metal. In at least some embodiments, the first metal layer can be titanium. Additionally, in at least some embodiments, a release layer 301 can be coated on the substrate 300 prior to depositing the first metal layer 302 at 102. The release layer 301 can be made from any suitable release material. For example, in at least some embodiments, the release layer 301 can be made from organic material dissolvable with UV light, thermal treatment or mechanical peel.
At 102, PVD deposition can be performed at a pressure of less than about 10 mTorr, a DC power of about 10 kW to about 20 kW, and with one or more process gases, such as argon, at a flow rate of 20 sccm to about 60 sccm.
The first metal layer 302 can be deposited to one or more suitable thicknesses. For example, the thickness of the first metal layer 302 can be about 100 nm to about 1000 nm. In at least some embodiments, the first metal layer 302 can have a thickness of about 100 nm.
After the first metal layer 302 is deposited on the substrate 300 to a desired thickness, at 102, the vacuum robot 242 can transfer the substrate 300 from the process chamber 214A to the process chamber 214B. For example, the process chamber 214B can be configured to etch the first metal layer 302 using one or more suitable etch processes to form one or more gate electrodes, e.g., a gate electrode 304. For example, in at least some embodiments, the first metal layer 302 can be etched using a dry etch process and a masking layer (not shown) to form the gate electrode 304 (
Next, a 104, the method 100 includes depositing a dielectric layer 306 atop the gate electrode 304 (
Next, at 106, the method 100 can include depositing a semi-conductive oxide layer 308 atop the dielectric layer 106 to cover a portion of the gate electrode forming the transistor channel (
At 106, RF PVD deposition can be performed using similar process parameters as described above with respect to 102, e.g., at a pressure of less than about 10 mTorr, an RF power of about 10 kW to about 20 kW, and with one or more process gases, such as argon, at a flow rate of 20 sccm to about 60 sccm.
In at least some embodiments, at 106, one or more known etch processes and masking layers (not shown) can be used to facilitate covering the gate electrode 104. For example, in at least some embodiments, the semi-conductive oxide layer 308 can be deposited to cover (or substantially cover) the dielectric layer 106. Thereafter, a masking layer can be deposited and an etch process, such as a dry etch plasma or wet etch process, can be performed to remove the semi-conductive oxide layer 308 from the dielectric layer 306 (e.g., from the right gate electrode). The process chamber 214D can be configured to perform, for example, the dry etch process.
Next, at 108, the method includes etching the dielectric layer 306 from a portion of the gate electrode that is not covered by the semi-conductive oxide layer 308 to form a gate access via 310 (
Next, at 110, the method 100 includes depositing a second metal layer 312 atop the dielectric layer 306 and the semi-conductive oxide layer 308, and within the gate access via 310, e.g., for gate, source, drain metal connectivity formation, (
At 110, PVD deposition can be performed at a pressure of less than about 10 mTorr, a DC power of about 10 kW to about 20 kW, and with one or more process gases, such as argon, at a flow rate of 20 sccm to about 60 sccm.
In at least some embodiments, at 110, one or more of the above-described etch processes and masking layers (not shown) can also be used for gate, source, drain metal connectivity formation.
Next, the method 100 can include depositing a polymer coating layer 314 (e.g., a photosensitive polymer coating layer,
For example, after the vias 316 are formed in the polymer coating layer 314, the vacuum robot 242 can transfer the substrate 300 for depositing a third metal (e.g., titanium, copper, or molybdenum) as barrier seed metal. The photoresist will be coated and lithography patterned to form the design of redistribution layer. The wafer then plated with copper to fill the vias 316 and form an at least one metal contact atop the polymer coating layer 314. For example, as shown in
The processes of the method 100 shown in
In at least some embodiments, the method 100 can optionally include removing the substrate 300 (and the release layer 301 if provided) after connecting the one or more electrical devices 320 to the metal contacts 318 and performing under bump metallization to form solder bumps 322 on a bottom surface of the dielectric layer (e.g., the formed TFT embedded in the first polymer coating layer). In some embodiments, one or more suitable molds 324 can be deposited to cover the one or more electrical devices 320, the metal contacts 318, and the last polymer coating layer (
The methods described herein can also be used in other FanOut process schemes. For example, while the method 100 has been described herein as an RDL first FanOut process scheme (e.g., RDL 1st is creating the RDLs of interconnects before connecting to the die/chips), the method 100 is not so limited. For example, the FanOut process scheme can include an RDL last (e.g., the dies are embedded/reconstituted into a wafer format and then the RDLs are formed on top of reconstituted package to form external connectivity).
While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof.