Semiconductor device manufacturing: process – Radiation or energy treatment modifying properties of... – Ionized irradiation
Reexamination Certificate
2002-04-22
2004-09-07
Coleman, W. David (Department: 2823)
Semiconductor device manufacturing: process
Radiation or energy treatment modifying properties of...
Ionized irradiation
C136S201000
Reexamination Certificate
active
06787485
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to an appliance for tempering a process item. Such an appliance is known, for example, from EP 0 662 247 B1. In addition to the appliance, a method for tempering a process item is presented.
The process item known from EP 0 662 247 B1 is a multilayer body which is manufactured by applying a functional layer to a substrate. In order that the functional layer and/or the substrate may exhibit a desired physical (electrical, mechanical, etc) and/or chemical property, a process is carried out on the process item or the layer and/or the substrate. The processing includes tempering the process item in the presence of a gas (process gas).
For tempering, the process item is arranged in a closed graphite tempering container. During the tempering process, the process item is exposed to a process gas with gaseous selenium. During the tempering process, the process item accepts a quantity of energy, a partial quantity of the quantity of energy being supplied to each layer. The tempering process takes place with, for example, a heating rate of 10° C. per second. A halogen lamp is used as the energy source of the quantity of energy. By means of the halogen lamp, the graphite tempering container is radiated by an electromagnetic radiation and the tempering container is heated by this means. Graphite exhibits a high absorption capability for the electromagnetic radiation in the spectral range of the halogen lamp. The quantity of energy absorbed by the graphite is supplied by thermal radiation and/or thermal conduction to the process item. The tempering container therefore functions as a secondary energy source or as an energy transmitter.
Graphite exhibits a high emission capability and a high thermal conductivity. When the process item is laid on the bottom of the tempering container, the supply of the energy quantity to a lower surface of the process item takes place, essentially, by thermal conduction. A quantity of energy is supplied to an upper surface of the process item by thermal radiation, thermal conductivity and convection.
The larger the process item (larger surface), the more different the materials used in the process item (for example strongly differing thermal expansion coefficient, differing absorption capability for the quantity of energy, etc) and the higher the tempering rate is (heating rate, cooling rate), the more difficult it is to control a temperature homogeneity or temperature inhomogeneity in the process item. The temperature inhomogeneity can lead to a mechanical stress in the process item and, therefore, to destruction of the process item. For this reason, the known appliance with the tempering container mainly suitable for tempering a single process item.
SUMMARY OF THE INVENTION
The object of the invention is to demonstrate how, using a single appliance, a plurality of process items can be simultaneously tempered while controlling a temperature homogeneity or temperature inhomogeneity in each of the process items.
In order to achieve the object, an appliance is specified for tempering a plurality of process items in a certain gas atmosphere by acceptance of a quantity of energy by a process item by means of absorption of a certain electromagnetic radiation and by acceptance of at least a further quantity of energy by at least one further process item by means of absorption of at least a further certain electromagnetic radiation. The appliance exhibits at least one device for producing the gas atmosphere, a tempering unit with at least one energy source for generating the electromagnetic radiation and at least one further tempering unit with at least one further energy source for generating the further electromagnetic radiation. The tempering unit and the further tempering unit are arranged relative to one another to form a tempering stack in such a way hat the process item can be arranged in a certain stacking direction of the tempering stack between the energy source and the further energy source and the further energy source can be arranged between the process item and the further process item.
The energy source is, for example, a heater plane, which is formed by a heater array. The heater array consists, for example, of rod-shaped halogen lamps or heating rods arranged parallel to one another. The process items are, for example, arranged between the heater planes in the tempering stack. Such an arrangement makes the appliance particularly suitable for the simultaneous tempering of a plurality of process items. The tempering units can be arranged both vertically and horizontally. At least one energy source is associated with each process item, the process item being arranged during tempering in the radiation field of the respective electromagnetic radiation. In order to accept the respective quantity of energy, the process items exhibit a corresponding absorption of the electromagnetic radiation. The arrangement ensures that each process item is provided with an energy density necessary for the tempering process. Mutual shadowing of the process items in the stack and, therefore, an uneven radiation of the process items due to the electromagnetic radiations does not occur. The (adjustable) gas atmosphere is, for example, characterized by a defined partial pressure of a gas or gas mixture (for example air). It is also conceivable for the gas atmosphere to be a vacuum.
In a particular embodiment, at least one of the tempering units exhibits at least one additional energy source for generating an additional quantity of energy and for accepting the additional quantity of energy by the process item of the tempering unit. The additional energy source makes it possible to take account of a different infrared absorption by the front surface and the rear surface of the process item and, by this means, to contribute to improving temperature homogeneity of the process item during the tempering process. In addition, an increase in the heating rate can be achieved by means of the additional energy source.
The acceptance of the additional quantity of energy can, essentially, take place by thermal conduction, thermal radiation and/or convection. In the case of thermal conduction, the process body is in contact with the energy source. Thermal radiation is at least partially absorbed by the process item and the process container in accordance with their absorption spectra within the spectral range of the heating element. In the case of convection, a gas for example, which can also be the process gas, is led past the process body. In this process, a quantity of energy can be exchanged between the gas and the process body.
In a particular embodiment, the additional energy source is an energy source for generating an additional electromagnetic radiation and the acceptance of the additional quantity of energy is an absorption of the additional electromagnetic radiation. In a further embodiment, the process item of the tempering unit is arranged between the energy source of the tempering unit and the additional energy source of the tempering unit. This makes it possible to heat different surfaces of the process item, for example an upper surface and a lower surface of a flat process item, differently. This is particularly advantageous when the process item is a multilayer body which exhibits layers of different material. The layers exhibit, for example, a different absorption capability for the electromagnetic radiation of the energy sources at the same thermal expansion coefficient. In order to avoid a temperature inhomogeneity in the thickness direction of the multilayer body, the layers are, for example, radiated with an electromagnetic radiation of different energy density (energy per unit area).
In a particular embodiment, the energy source, the further energy source and/or the additional energy source can be triggered independently of one another. The quantity of energy which is supplied to the process items or different layers of the process items can be individually adjusted or regulated. As an example, two adjacent temperin
Coleman W. David
Shell Solar GmbH
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