1. Field of Art
The present invention relates to a radical reactor for depositing one or more layers of materials on a substrate using atomic layer deposition (ALD).
2. Description of the Related Art
An atomic layer deposition (ALD) is a thin film deposition technique for depositing one or more layers of material on a substrate. ALD uses two types of chemical, one is a source precursor and the other is a reactant precursor. Generally, ALD includes four stages: (i) injection of a source precursor, (ii) removal of a physical adsorption layer of the source precursor, (iii) injection of a reactant precursor, and (iv) removal of a physical adsorption layer of the reactant precursor. ALD can be a slow process that can take an extended amount of time or many repetitions before a layer of desired thickness can be obtained. Hence, to expedite the process, a vapor deposition reactor with a unit module (so-called a linear injector), as described in U.S. Patent Application Publication No. 2009/0165715 or other similar devices may be used to expedite ALD process. The unit module includes an injection unit and an exhaust unit for a source material (a source module), and an injection unit and an exhaust unit for a reactant (a reactant module).
A conventional ALD vapor deposition chamber has one or more sets of reactors for depositing ALD layers on substrates. As the substrate passes below the reactors, the substrate is exposed to the source precursor, a purge gas and the reactant precursor. The source precursor molecules deposited on the substrate reacts with reactant precursor molecules or the source precursor molecules are replaced with the reactant precursor molecules to deposit a layer of material on the substrate. After exposing the substrate to the source precursor or the reactant precursor, the substrate may be exposed to the purge gas to remove excess source precursor molecules or reactant precursor molecules from the substrate.
Embodiments relate to depositing one or more layers of material on a substrate using a radical reactor with a plurality of plasma chambers, each under different conditions for generating radicals of different gases. The radicals of gases may be formed in the plasma chambers under different conditions. Hence, the radical reactor is formed with a plurality of plasma chambers that are placed in appropriate conditions for generating the radicals of gases injected into the plasma chambers.
In one embodiment, the radical reactor has a body placed adjacent to a susceptor on which the substrate is mounted. The body may be formed with a first plasma chamber configured to receive a first gas, a second plasma chamber configured to receive a second gas, and a mixing chamber connected to the first plasma chamber and the second plasma chamber to receive radicals of the first gas and radicals of the second gas from the first plasma chamber and the second plasma chamber. The plasma chambers are located remotely from the substrate to prevent voltage applied to the plasma chambers from affecting the substrate or devices formed on the substrate.
In one embodiment, a first inner electrode extends within the first plasma chamber. The first inner electrode is configured to generate the radicals of the first gas within the first plasma chamber by applying a first voltage difference across the first inner electrode and a first outer electrode. A second inner electrode extends within the second plasma chamber. The second inner electrode is configured to generate the radicals of the second gas within the second plasma chamber by applying a second voltage difference across the second inner electrode and a second outer electrode. The first voltage difference is greater or smaller than the second voltage difference.
In one embodiment, the body is further formed with a mixing chamber in which the radicals of the first gas and the radicals or the second gas are mixed before coming into contact with the substrate.
In one embodiment, the body is further formed with a first channel connecting the first plasma chamber to a first gas source and a second channel connecting the second plasma chamber to a second gas source.
In one embodiment, the body is further formed with at least one first perforation connecting the first plasma chamber with the mixing chamber and at least one second perforation connecting the second plasma chamber with the mixing chamber.
In one embodiment, the first channel, the first electrode, the first plasma chamber, and the first perforation are aligned along a first plane. The second channel, the second electrode, the second plasma chamber, and the second perforation are also aligned along a second plane oriented with an angle with respect to the first plane.
In one embodiment, the first perforation and the second perforation are oriented toward a same interior area within the mixing chamber to facilitate mixing of the radicals.
In one embodiment, the radical reactor is placed above the susceptor to inject the radicals as the susceptor moves below the radical reactor.
In one embodiment, the body is formed with two outlets at opposite sides of the radical reactor.
In one embodiment, the body is formed with a first mixing chamber in which the radicals of the first gas and the radicals of the second gas are injected from the first plasma chamber and the second plasma chamber for mixing, a second mixing chamber facing the substrate for allowing mixed radicals to come in contact with the substrate, and a communication channel connecting the first mixing chamber and the second mixing chamber.
In one embodiment, the radical reactor is used for performing an atomic layer deposition (ALD) on the substrate.
Embodiments also relate to a deposition apparatus for depositing one or more layers of material on a substrate using atomic layer deposition (ALD). The deposition apparatus includes a radical reactor with a plurality of radical reactors formed therein to generate radicals of gases under different conditions.
Embodiments also relate to a method of depositing one or more layers on a substrate using atomic layer deposition (ALD). The method involves injecting a first gas into a first plasma chamber formed in a radical reactor. Radicals of the first gas are generated in the first plasma chamber under a first condition. A second gas is injected into a second plasma chamber formed in the radical reactor. Radicals of the second gas are generated in the second plasma chamber under a second condition different from the first condition. The radicals of the first gas and the radicals of the second gas are mixed in a mixing chamber formed in the radical reactor. The mixed radicals are injected onto the substrate.
In one embodiment, the first condition relates to applying a first level of voltage across an inner electrode and an outer electrode of the first plasma chamber and the second condition relates to applying a second level of voltage across an inner electrode and an outer electrode of the second plasma chamber.
Embodiments are described herein with reference to the accompanying drawings. Principles disclosed herein may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. In the description, details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the features of the embodiments.
In the drawings, like reference numerals in the drawings denote like elements. The shape, size and regions, and the like, of the drawing may be exaggerated for clarity.
Embodiments relate to providing two or more plasma chambers in a radical reactor to generate radicals of gases under different conditions for use in atomic layer deposition (ALD) process. The radical reactor has a body with multiple channels and corresponding plasma chambers. Electrodes are placed in and around each plasma chamber to generate plasma when voltage is applied across the electrodes. The plasma generates radicals of gas present in the plasma chamber. The radicals generated in the plasma chamber are then injected into a mixing chamber for mixing with radicals of another gas from another plasma chamber, and then injected onto the substrate. By providing two or more plasma chambers in a radical reactor, the need for multiple radical reactors can be obviated.
A plasma chamber described herein refers to a cavity into which a gas is injected for generating radicals of the gas. Electrodes are placed in and/or around the plasma chamber to generate plasma in the plasma chamber as voltage is applied across the electrodes. The plasma chamber may be located remotely from a substrate to prevent plasma or electric sparks from affecting the substrate or devices on the substrate.
A mixing chamber described herein refers to a cavity in which radicals of two or more gases are mixed.
The process chamber enclosed by the walls 110 may be maintained in a vacuum state to prevent contaminants from affecting the deposition process. The process chamber contains a susceptor 128 which receives a substrate 120. The susceptor 128 is placed on a support plate 124 for a sliding movement. The support plate 124 may include a temperature controller (e.g., a heater or a cooler) to control the temperature of the substrate 120. The linear deposition device 100 may also include lift pins (not shown) that facilitate loading of the substrate 120 onto the susceptor 128 or dismounting of the substrate 120 from the susceptor 128.
In one embodiment, the susceptor 128 is secured to brackets 210 that moves across an extended bar 138 with screws formed thereon. The brackets 210 have corresponding screws formed in their holes receiving the extended bar 138. The extended bar 138 is secured to a spindle of a motor 114, and hence, the extended bar 138 rotates as the spindle of the motor 114 rotates. The rotation of the extended bar 138 causes the brackets 210 (and therefore the susceptor 128) to make a linear movement on the support plate 124. By controlling the speed and rotation direction of the motor 114, the speed and direction of the linear movement of the susceptor 128 can be controlled. The use of a motor 114 and the extended bar 138 is merely an example of a mechanism for moving the susceptor 128. Various other ways of moving the susceptor 128 (e.g., use of gears and pinion at the bottom, top or side of the susceptor 128) may be used. Moreover, instead of moving the susceptor 128, the susceptor 128 may remain stationary and the reactors 136 may be moved.
One or more of the reactors 320, 334, 364, 368 are connected to gas pipes via inlet 330 to receive source precursor, reactor precursor, purge gas and/or other materials. The materials provided by the gas pipes may be (i) injected onto the substrate 314 directly by the reactors 320, 334, 364, 368, (ii) after mixing in a chamber inside the reactors 320, 334, 364, 368, or (iii) after conversion into radicals by plasma generated within the reactors 320, 334, 364, 368. After the materials are injected onto the substrate 314, the redundant materials may be exhausted through outlets 330.
Embodiments of radical reactors described herein can be used in deposition devices such as the linear deposition device 100, the rotating deposition device 300 or other types of deposition devices.
The injector 136A receives gas through a pipe 412 and injects the gas onto the substrate 120 as the susceptor 128 moves below the injector 136A. The injected gas may be a source gas, a reactant gas, purge gas or a combination thereof. After being injected onto the substrate 120, excess gas in the injector 136A is discharged via an outlet 422. The outlet 422 is connected to a pipe (not shown) to discharge the excess gas outside the linear deposition device 100.
The radical reactor 136B receives gases via pipes (not shown) and has two plasma chambers. Channels are formed in the body of the radical reactor 136B to convey the received gases to the plasma chambers. Two inner electrodes 410, 414 extend longitudinally across the radical reactor 137B and are connected to a voltage source (not shown) or ground (not shown) via wires 402, 404. The inner electrodes 410, 414 are placed inside plasma chambers, as described below in detail with reference to
In other embodiments, one or more of the channels, the holes, plasma chambers and slits are not aligned along the same plane but placed in different arrangements. For example, a channel may be provided at a horizontally left or right side of the channel or vertically above the channel. Various other arrangements of channels, holes, plasma chambers and slits can also be used.
In the embodiment of
The slits 604 and 608 are oriented toward an area of the mixing chamber 530 (around point C1 of the mixing chamber 530 in
As seen in Table 1 below, different types of gases have different levels of ionization energy. Hence, different levels of voltage are applied between the inner electrode and the outer electrode of the plasma chamber depending on the types of gas supplied to the plasma chamber. To generate radicals of different gases, a corresponding number of plasma chambers and sets of electrodes may be needed due to different levels of ionization energy for different gases.
In the embodiment of
In summary, the radical reactor 136B functions as two radical reactors with one plasma chamber. By incorporating two radical reactors into one radical reactor, the space and cost of the linear deposition device 100 can be reduced.
The radicals of the first and second gases are generated in the plasma chambers 832, 834 by applying voltage across the inner electrodes 818, 820 and outer electrodes 822, 824. The generated radicals are then are injected into a mixing chamber 830 via slits 826, 828. The mixing chamber 830 may have sufficient height to allow adequate mixing of the radicals as the radicals travel down the mixing chamber 830 onto the substrate 120. The remaining radicals and/or gases are discharged via an outlet 842.
The radical reactors of various other configurations may also be used. Although embodiments of radical reactors in
A second gas is injected 1030 into a second plasma chamber of the same radical reactor via another channel connected to a gas source. Within the second plasma chamber, radicals of the first gas are generated 1040 under a second condition. The second condition may include applying a second level of voltage difference across an inner electrode and an outer electrode associated with the second plasma chamber. The second condition may include maintaining the pressure and temperature of plasma or gas within the second plasma chamber within certain ranges At least one element of the second condition is different from the counterpart element of the first condition.
The radicals generated in the first and second plasma chambers are then injected into a mixing chamber where the radicals are mixed 1050. The mixed radicals are then injected 1060 onto the substrate.
The sequence of processes in
Although the present invention has been described above with respect to several embodiments, various modifications can be made within the scope of the present invention. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.
This application claims priority under 35 U.S.C. §119(e) to co-pending U.S. Provisional Patent Application No. 61/410,796, filed on Nov. 5, 2010, which is incorporated by reference herein in its entirety.
Number | Date | Country | |
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61410796 | Nov 2010 | US |