Patent Application
20180254203
Examples of the present disclosure generally relate to apparatuses and methods for reducing particle formation on substrates in a semiconductor substrate processing system.
Electronic devices, such as flat panel displays and integrated circuits, are commonly fabricated by a series of processes in which layers are deposited on a surface of a substrate and the deposited material is etched into desired patterns. The processes commonly include physical vapor deposition (PVD), chemical vapor deposition (CVD), plasma enhanced CVD (PECVD), and other plasma processing methods.
One problem encountered during the various stages of processing is the concentration of contaminating particles, such as fluorine byproducts, on the substrate surface. When the substrate is heated on a heater pedestal in the load lock chamber after processing these contaminating particles generally volatize to a gas and then solidify and accumulate on the colder ceiling or sidewalls of the load lock chamber. Further heating generally causes the accumulated particles to crack, flake off of the ceiling or sidewalls of the load lock chamber, and fall back onto the substrate surface. These surface contaminating particles are detrimental to device functionality. Heating the load lock chamber in its entirety, including the colder ceiling or sidewalls, to reduce particle contamination would be inefficient and would diminish the functionality of various chamber components, which may be inoperable at higher temperatures.
Therefore, there is a need in the art for improved apparatuses and methods that effectively reduce the generation of contaminating particles on the substrate surface after etch processes.
The present disclosure generally relates to apparatuses and methods for reducing particle contamination on substrate surfaces using a top heater liner over a heater pedestal in a load lock chamber of a semiconductor substrate processing system. In one example the apparatus is a load lock chamber. The load lock chamber includes a chamber body having chamber walls and a chamber lid. Inner surfaces of the chamber walls and a bottom surface of the chamber lid define an internal volume. A heater pedestal is disposed in the internal volume. A top heater liner is disposed in contact with the heater pedestal. The top heater liner includes a top plate. At least one wall is disposed in contact with the top plate and the heater pedestal and spaces the top plate above the heater pedestal. The at least one wall has two substrate transfer openings disposed 180 degrees apart.
In another example the apparatus is a load lock chamber. The load lock chamber includes a chamber body having chamber walls and a chamber lid. Inner surfaces of the chamber walls and a bottom surface of the chamber lid define an internal volume. A heater pedestal is disposed in the internal volume. A top heater liner is disposed in contact with the heater pedestal. The top heater liner includes a top plate, at least two walls disposed in contact with the top plate and the heater pedestal and spacing the top plate above the heater pedestal, two substrate transfer openings defined between the at least two walls and below the top plate, the substrate transfer openings disposed 180 degrees apart.
In yet another example, the apparatus is a top heater liner. The top heater liner includes a cylindrical top plate and a cylindrical top plate and at least one wall disposed in contact with the top plate. The at least one wall has two substrate transfer openings disposed 180 degrees apart.
So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to examples, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary examples and are therefore not to be considered limiting of its scope, may admit to other equally effective examples.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one example may be beneficially incorporated in other examples without further recitation.
The present disclosure generally relates to apparatuses and methods for reducing particle contamination on substrate surfaces in a semiconductor substrate processing system. In one example, the apparatus is embodied as a load lock chamber. The load lock chamber includes a top heater liner disposed over and coupled to a heater pedestal. The top heater liner generally includes a perforated or solid top plate and one or more walls, which support the top heater liner over the heater pedestal. Since the top heater liner is in contact with the heater pedestal, the top heater liner is generally heated to a temperature at which substrate surface contaminating particles are volatile, such as greater than about 100 degrees Celsius (° C.). In operation, volatile fluorine passing through or adjacent to the hot top heater liner remains in gaseous form and thus are pumped out of the load lock chamber. The top heater liner thus advantageously assists in reducing the potential for contaminating particles depositing on the substrate surface and, thus, improves overall production yield.
The factory interface 114 is maintained at a substantially atmospheric pressure and includes one or more robots 104 for transferring substrates between cassettes 102 coupled to the factory interface 114 and the load lock chamber 105. The load lock chamber 105 is operational to receive the substrates at atmospheric pressure from the factory interface 114 and then pump down the interior volume of the load lock chamber 105 to a low pressure (i.e., vacuum), upon which the substrates are generally then transferred from the load lock chamber 105 into the transfer chamber 112 by a second robotic arm 110 disposed in the transfer chamber 112.
The second robotic arm 110 is configured to transfer substrates into the substrate processing chambers 108a-f for processing. Each substrate processing chamber 108a-f can be outfitted to perform a substrate processing operation such as dry etch processes, cyclical layer deposition (CLD), atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), pre-clean, substrate degas, substrate orientation, and other substrate processes. At least one of the substrate processing chambers 108a-f is configured to perform a process that uses a halogen containing gas. For example, at least one of the substrate processing chambers 108a-f is configured etch the substrate using fluorine or a fluorine containing gas. After processing in one or more of the substrate processing chambers 108a-f, the substrates are transferred back to the load lock chamber 105 by the second robotic arm 110, and ultimately back through the factory interface 114 to the cassettes 102.
At least one of the substrate processing chambers 108a-f is illustratively described as a processing chamber for etching silicon; however, the disclosure also applies to processing chambers configured for performing other processes. As discussed above, one problem encountered during the various stages of processing is the concentration of contaminating particles on the substrate surface. For example, silicon fluoride (SiF) is a common byproduct of silicon etching, and is volatile at temperatures greater than about 100 degrees Celsius. Throughout processing, SiF surface contaminating particles, or etch residue, accumulate on the substrate surface. When the processed substrate is vented to atmosphere in the load lock chamber 105, at least some of these surface contaminating particles generally remain on the substrate surface. When the substrate is heated in the pair of load lock chamber 105, the surface contaminating particles generally volatize, however, when the volatized byproducts including fluorine from the SiF contact the colder lid or sidewalls of the load lock chamber 105, the fluorine reacts with the metals on those surfaces and generally forms a film that is susceptible to crack, flake off, and fall back onto the substrate surface as a contaminant. As discussed below, the pair of load lock chamber 105 are configured to substantially reduce the potential for the generation of films on the surfaces of the load lock chamber 105 that could potentially become contaminating particles on the substrate surface.
The load lock chamber 105 is illustratively shown as a single substrate supporting load lock chamber; however, the disclosure also applies to load lock chambers configured to support two or more substrates. For example, the disclosure also applies to a stacked load lock chamber having a lower slot and an upper slot, the lower slot configured to support a first substrate and the upper slot configured to support a second substrate. Additionally, the load lock chamber 105 is illustratively shown as a load lock chamber configured to support a circular substrate, such as a 300 millimeter (mm) substrate; however, the disclosure also applies to substrates of any shape and any dimension and load lock chambers configured for support thereof.
A heater pedestal 210 and a top heater liner 212 are disposed in the internal volume 224. The heater pedestal 210 is coupled to a support shaft 216 that extends through the chamber body 204. A resistive heating element 202 is disposed in the heater pedestal 210 and is coupled to a power source (not shown) by a cable 218 that extends through the support shaft 216. The heating element 202 may alternatively be suitable heating element(s) other than resistive heaters.
The top heater liner 212 generally includes a top plate 260 and one or more walls 262. The top plate 260 is spaced a distance 226 from the upper surface 210a of the heater pedestal 210. The distance 226 is generally between about 1000 mils and about 2000 mils, for example, about 1300 mils. The top plate 260 is spaced a distance 228 from the bottom surface 208b of the chamber lid 208. The distance 228 is generally between about 50 mils and about 200 mils, for example, about 100 mils.
The top heater liner 212 is manufactured from a material having high thermal conductivity, such as a metal, for example aluminum. The walls 262 couple the top heater liner 212 and the heater pedestal 210 and conduct heat from the heater pedestal 210 to the top heater liner 212. This coupling provides for a more robust contact between the top heater liner 212 and the heater pedestal 210. The robust contact between the top heater liner 212 and the heater pedestal 210 increases the heat transfer from the heater pedestal 210 to the perforated top plate 260.
As shown in
The height of the substrate transfer opening 302 is great enough to allow a robot, such as the second robotic arm 110, and the substrate 220 to pass therethrough. Because the first wall 304a and the second wall 304b are spaced apart, the substrate transfer opening 302 is also wide enough to accommodate the substrate 220 passing therethrough. In an example using a 300 mm substrate, the substrate transfer opening 302 is generally wider than 350 mm. In an example using a 450 mm substrate, the space 302 is generally wider than 500 mm. In an example using a 200 mm substrate, the substrate transfer opening 302 is generally wider than 250 mm. While the example shown in
The open area of the top plate 260, or size and density of the openings 306, is generally selected to efficiently facilitate volitzation of etch residue on the substrate surface or the colder chamber walls and lids and allow the volatized material 450 to pass therethrough. In other words, the open area is selected to facilitate volitzation of etch residue into a gaseous, volatized material 450. The open area of the top plate 260 is generally selected in response to the expected size of the particles of the etch residue such that it provides a physical barrier to flakes from the etch residue.
As discussed above, etch residue generally accumulates on the surface of the substrate 220 during the various stages of processing. When the substrate 220 enters the load lock chamber 105 after undergoing various processes, such as silicon etching, etchant SiF byproducts have generally accumulated on the surface of the substrate 220. In the load lock chamber 105, the substrate 220 is heated on the heater pedestal 210. The heater pedestal 210 is generally heated to a temperature between about 200° C. and about 350° C., whereas the chamber body is generally at a temperature between about 65° C. and about 90° C. In comparison, the top plate 260 is generally heated to a temperature greater than about 100° C., or a temperature at which the etch residue becomes volatile, due to the conductivity of the walls 304.
As shown in
As shown in
The diameter of the top heater liner 512 is generally selected as described above with reference to the top heater liner 212.
Etch residue generally accumulates on the surface of the substrate 220 during the various stages of processing. When the substrate 220 enters the load lock chamber 105 after undergoing various processes, such as silicon etching, etchant SiF byproducts have generally accumulated on the surface of the substrate 220. In the load lock chamber 105, the substrate 220 is heated on the heater pedestal 210. The heater pedestal 210 is generally heated to a temperature between about 200° C. and about 350° C., whereas the chamber body is generally at a temperature between about 65° C. and about 90° C.
As shown in
Benefits of the apparatuses and methods described herein include further reduction or elimination of particle contamination on the surface of a substrate in a load lock chamber after the substrate has been processed. This reduction or elimination of substrate surface particle contamination results in increased throughput, uniformity, and overall semiconductor substrate functionality.
While the foregoing is directed to examples of the present disclosure, other and further examples of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
