Cleaning and liquid contact with solids – Processes – With work or work parts movable during treatment
Reexamination Certificate
1999-07-07
2001-10-23
Gulakowski, Randy (Department: 1746)
Cleaning and liquid contact with solids
Processes
With work or work parts movable during treatment
C134S033000, C134S042000, C134S066000, C134S159000
Reexamination Certificate
active
06306224
ABSTRACT:
DESCRIPTION
Process and device for treatment of objects, in particular disk-like objects such as metal sheets, glass panes, PCBs and ceramic substrates
BACKGROUND OF THE INVENTION
The invention relates to a process for treatment of objects, in particular disk-like objects such as metal sheets, glass panes, PCBs and ceramic substrates, where the objects are supplied to a bath containing fluid, rotated by means of a rotation device about the rotational axis of said rotation device with permanent alignment of the objects on said rotational axis, and at the same time transported through the bath and moved away translationally after the bath, with the objects being retained, during their transport through the bath in receptacles of the rotation device that are radial relative to the rotational axis, by a securing element peripherally surrounding said rotation device. The invention also relates to a device for treatment of objects, in particular disk-like objects such as metal sheets, glass panes, PCBs and ceramic substrates, comprising a bath fillable with fluid such as a chemical bath for treatment of the objects, a feed device arranged upstream of the bath, a conveying device passing the objects through the bath in the form of a rotation device with radial receptacles intended for receiving the objects, a securing element provided inside the bath and extending in the peripheral area of the receptacles for retaining the objects in the receptacles, a removal device arranged downstream of the bath, and the washing and/or drying stage arranged downstream of the bath with associated transport device.
In order to treat, for example, oxide layers of semiconductor wafers by etching in diluted hydrofluoric acid, it is known to place the wafers in hurdles made of plastic and then to successively immerse these either manually or with a handling unit in various chemical baths or to spray them with chemicals. The drawback of this procedure is that the placing of the wafers into the hurdles and the removal of the wafer from these hurdles necessitate additional procedural steps which are particularly unwelcome when the processes preceding or following the chemical treatment are to be performed continuously.
A further drawback of the known process is that the supply of chemicals to the wafers being treated is restricted by the hurdles. In addition, fluids like water and residual chemicals can remain in the pockets of the hurdles during drying unless expensive drying processes are used.
In another known process, the wafers are passed by a belt conveyor or transport belt through a spray device in which they are sprayed with chemicals. On the one hand it is not assured by spraying that the wafers are completely wetted, and on the other hand the treatment duration is restricted and/or the necessary equipment must be designed with a very high volume.
DE-PS 639 104 describes a device for the treatment of metal sheets that are passed through a bath filled with liquid. Here the flat objects are picked up by a rotation device and passed through the bath. Downstream of the bath is a transport device with which the objects are moved translationally. The rotation device itself is supplied with the objects from a stack. Furthermore, stationary guide strips run peripherally to a rotation device, along which the metal sheets slide in order to ensure that these metal sheets remain inside the rotation device.
A transport device is known from EP 0 070 694 A1 in which objects such as sockets are transported by means of a rotary plate that is surrounded on the circumferential side by an endless belt. The rotary plate itself is rotatable about a vertically running rotational axis. The objects are moved in the entry area of the rotary plate relative to a fixed guide plate.
A spoked-wheel transport device described in DE-OS 1 951 200 provides for a conveying device in the form of a spoked wheel for cooling slabs.
A process for metallization of the surfaces of flat objects is described in DE 35 43 286 C2. The objects here pass through several cleaning and drying stations.
A device for turning PCBs is known from EP 0 637 561 A1, in which a rotating wheel in the form of a fan-shaped magazine is used. Here the objects are conveyed translationally to the magazine and then inside the latter above the rotational axis.
SUMMARY OF THE INVENTION
The problem underlying the present invention is to develop a process and a device of the type mentioned at the outset such that it is assured in addition to integration in a continuous process that the objects can be treated with the fluid necessary for treatment to the required extent without any damage being incurred. In particular, relative movements between the objects and the rotation device during passage of the objects through the bath are to be prevented.
The problem is solved in accordance with the invention substantially in that the objects are retained in the receptacle during their passage through the bath by a flexible element as a securing element that is moved synchronously with the rotation device, in that the objects are radially supplied to the rotation device via a conveyor belt, and in that the objects are supplied to at least one washing and/or drying stage after leaving the bath. The objects are here placed in receptacles of a rotating conveying device that are radial to the rotational axis, the objects being secured during their passage through the bath on their sides facing away from the rotational axis. The rotary axes themselves can be supplied to the rotating conveying device such as a reversing wheel, or removed from the latter, by a conveyor such as a belt conveyor. They are secured by a flexible element moving synchronously with the rotating conveying device and surrounding the latter peripherally in the lower part, hence preventing a relative movement between the objects and the securing element and thus also preventing otherwise possible damage to thin objects.
In accordance with the invention, transfer of the objects is effected in a continuous or virtually continuous process from a first conveying device such as a belt conveyor to the rotation device, which can be described as a modified reversing wheel, using which the objects are passed through the bath in order to then be transferred to a further translational conveying device such as a conveyor belt. The objects can then be passed on to a washing and/or drying stage.
To ensure in the washing and/or drying stage that all areas of the objects are cleaned and dried to the necessary extent, a further embodiment of the invention provides that the objects are supported during their passage through the washing and/or drying stage at different points in the area of its transport section. In other words, the support points of the objects during their passage through the washing and/or drying stage differ from one another.
To prevent any uncontrolled movement of the objects during their passage through the washing and/or drying stage, it is further provided that the objects are subjected to pressure in the direction of their supports.
A device of the type mentioned at the outset is characterized in that the securing element is a flexible element moving synchronously with the rotation device.
The rotation device here comprises in particular two cheeks at a distance from one another and extending from a common shaft passed through by the axis, said cheeks having slots opened radially towards the periphery relative to the axis and serving as receptacles.
The cheeks themselves are preferably designed as circular discs and have penetrations.
On the outside along each cheek, a lateral retaining element such as a limiting disk mounted on the shaft should be arranged that is preferably connected to the respective cheek. The corresponding retaining elements ensure that the objects are not axially movable inside the slots to an inadmissible extent.
To ensure that the objects cannot slip out of the slots during passage through the bath, the flexible element such as a belt is provided for securing them in accordance wit
Heyer Fritz
Schum Berthold
Wandel Gernot
Angewandte Solarenergie--ASE GmbH
Chaudhry Saeed
Dennison, Scheiner Schultz & Wakeman
Gulakowski Randy
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