Abstract:
A method is provided for treating wafers (16) on a low mass support (18). The method includes mounting a temperature sensor (28) in proximity to the wafer (16), which is supported on the low mass support (18), such that the sensor (28) is only loosely thermally coupled to the wafer (16). A temperature controller (80) is programmed to critically tune the wafer temperature in a temperature ramp, though the controller directly controls the sensor temperature. A wafer treatment, such as epitaxial silicon deposition, is started before the sensor temperature has stabilized. Accordingly, significant time is saved for the treatment process, and wafer throughput improved.
Abstract:
Silicon-on-insulator (SOI) structures are provided by forming a single-crystal insulator over a substrate, followed by heteroepitaxy of a semiconductor layer thereover. Atomic layer deposition (ALD) is preferably used to form an amorphous insulator, followed by solid phase epitaxy to convert the layer into a single-crystal structure. Advantageously, the crystalline insulator has a lattice structure and lattice constant closely matching that of the semiconductor formed over it, and a ternary insulating material facilitates matching properties of the layers. Strained silicon can be formed without need for a buffer layer. An amorphous SiO2 layer can optionally be grown underneath the insulator. In addition, a buffer layer can be grown, either between the substrate and the insulator or between the insulator and the semiconductor layer, to produce desired strain in the active semiconductor layer.
Abstract:
Thin films are formed by formed by atomic layer deposition, whereby the composition of the film can be varied from monolayer to monolayer during cycles (301) or (450, 455, 460, 470) including alternating pulses of self-limiting chemistries. In the illustrated embodiments, varying amounts of impurity sources (306 or 460) are introduced during the cyclical process. A graded gate dielectric (72) is thereby provided, even for extremely thin layers. The gate dielectric (72) as thin as 2 nm can be varied from pure silicon oxide to oxynitride to silicon nitride. Similarly, the gate dielectric (72) can be varied from aluminum oxide to mixtures of aluminum oxide and a higher dielectric material (e.g., ZrO2) to pure high k material and back to aluminum oxide. In another embodiment, metal nitride (432) (e.g., WN) is first formed as a barrier for lining dual damascene trenches and vias. During the alternating deposition process, copper can be introduced, e.g., in separate pulses, and the copper source pulses (460) can gradually increase in frequency, forming a graded transition region (434), until pure copper (436) is formed at the upper surface. Advantageously, graded compositions in these and a variety of other contexts help to avoid such problems as etch rate control, electromigration and non-ohmic electrical contact that can occur at sharp material interfaces.
Abstract:
An improved apparatus and method for substrate layer deposition in which substrate layers are grown by carrier gas (C, D) delivery of sequential pulses of reactants (A, B) to the substrate surfaces. (5) At least one of the reactants (A, B) comprises excited species, e.g., radicals. In a specific embodiment, the apparatus of this invention provides sequential repeated pulses of reactants in a flow of carrier gas (4, 13) for reaction at a substrate surfaces. The reactant pulses are delivered with sufficient intervening delay times to minimize undesirable reaction between reactants (A, B) in adjacent pulses in the gas phase or undesired uncontrolled reactions on the substrate surface (5).
Abstract:
Disclosed is a carrier (10) comprising three support elements (50) connected by an underlying frame (15). The periphery of a wafer (45) rests upon the support elements (50). Also disclosed is a wafer handler (25) with a plurality of arms (100). Spacers (85) space the carrier (10) above a base plate (90) associated with a station in a wafer handling area. An arm (100) slides beneath the frame (15) and between the spacers (85), but the handler (25) does not contact the wafer (45). A method of using the handler (25) and carrier (10) is provided where the handler (55) lifts and rotates the carrier (10) with the wafer (45) through various stations (112, 125, 126 and 130) in a wafer handling area (95). A control device (33) reduces the handler speed only at critical points of the processing cycle. The handler (55) is capable of moving a plurality of carriers (10) and wafers (45) simultaneously.
Abstract:
Methods for depositing epitaxial films such as epitaxial Ge and SiGe films. During cooling from high temperature processing (305) to lower deposition temperatures (315) for Ge-containing layers, Si or Ge compounds are provided (310) to the substrate. Smooth, thin, relatively defect-free Ge or SiGe layers (110) result. Retrograded relaxed SiGe (115) is also provided between a relaxed, high Ge-content seed layer (110) and an overlying strained layer (120).
Abstract:
Methods are provided for forming uniformly thin layers in magnetic devices. Atomic layer deposition (ALD) can produce layers that are uniformly thick on an atomic scale. Magnetic tunnel junction dielectrics, for example, can be provided with perfect uniformity in thickness of 4 monolayers or less. Furthermore, conductive layers, including magnetic 12, 16 and non-magnetic layers 14, can be provided by ALD without spiking and other non-uniformity problems. The disclosed methods include forming metal oxide layers by multiple cycles of ALD and subsequently reducing the oxides to metal. The oxides tend to maintain more stable interfaces during formation.
Abstract:
Methods and apparatuses are provided for cooling semiconductor substrates prior to handling. In one embodiment, a substrate and support structure combination is lifted after high temperature processing to a cold wall of a thermal processing chamber, which acts as a heat sink. Conductive heat transfer across a small gap from the substrate to the heat sink speeds wafer cooling prior to handling the wafer (e.g., with a robot). In another embodiment, a separate plate is kept cool within a pocket during processing, and is moved close to the substrate and support after processing. In yet another embodiment, a cooling station between a processing chamber and a storage cassette includes two movable cold plates, which are movable to positions closely spaced on either side of the wafer.