JP2921067B2 - Plasma cleaning equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a plasma cleaning apparatus, and more particularly, to a method for removing an oxide film formed on a surface of a substrate, a wafer, or the like with a mixed gas of a hydrogen gas and a diluent gas. Means.

(Prior Art) An oxide film is likely to be formed on the surface of a substrate or a wafer on which a semiconductor is mounted, when the surface is exposed to air. When an oxide film is formed on the surface of a substrate or a wafer, problems such as deterioration in adhesion of the metal film on the metal surface occur. Therefore, conventionally, acid cleaning has been performed to remove the oxide film. .
In acid cleaning, the substrate is immersed in a cleaning solution such as sulfuric acid and hydrogen peroxide, and the metal surface is lightly etched.
This is to remove the oxide film chemically.

(Problems to be Solved by the Invention) However, when the acid cleaning means is applied to a composite material in which a semiconductor chip or the like is mounted on a substrate, there is a problem that the semiconductor chip or the like is damaged.

Therefore, an object of the present invention is to provide a cleaning means for a substrate, a wafer, or the like which can solve the problem of the conventional means.

(Means for Solving the Problems) For this purpose, the present invention provides a casing to which a gas for plasma discharge is supplied, an electrode portion for applying a high voltage to generate plasma inside the casing, and an inside of the casing. A vacuum pump for sucking the gas, and an inlet / outlet means for taking in and out the object to be cleaned into / from the casing through an opening formed in the casing. A plasma cleaning apparatus using a gas, wherein the loading / unloading unit includes a mounting unit for mounting a plurality of the objects to be cleaned,
A lid member attached to a rear portion of the mounting portion, and a forward-backward retreat means for moving the mounting portion forward and backward with respect to the casing and moving the mounting portion into and out of the casing from the opening, Further, a conveyor for transporting the object to be cleaned to the mounting portion, and a transfer means for transferring the object to be cleaned transported by the conveyor to the mounting portion are provided, and the mounting portion is opened by the advancing and retreating means. The objects to be cleaned, which have been conveyed by the conveyor by the transfer means, are sequentially transferred onto the mounting section while the transfer section is being moved from the section to the inside of the casing. And the cover member closes the opening when completely inserted into the opening.

(Operation) In the above configuration, when a high voltage is applied to the electrode portion after the object to be cleaned such as a substrate or a wafer is housed inside the casing, hydrogen gas plasma is generated inside the casing, and hydrogen gas molecules are generated. The oxide film on the surface of the object to be cleaned is reduced and removed by high-speed movement of ions and ions.

Example Next, an example of the present invention will be described with reference to the drawings.

1 is a plan view of the plasma cleaning apparatus, FIG. 2 is a side view, and FIG. 3 is a sectional view. Reference numeral 1 denotes a cylindrical glass casing having an opening 2 at the front end face thereof. An electrode portion 3 made of an aluminum plate is provided on a peripheral surface of the casing 1. Reference numeral 4 denotes a power supply for applying a high-frequency AC voltage to the electrode unit 3.

A pipe 5 is connected to an upper part of the casing 1,
A gas for plasma discharge is supplied from the pipe 5 into the casing 1. A rotary vacuum pump 6 for sucking gas in the casing 1 is connected to a lower portion of the casing 1, and a valve 7 is connected to a rear end surface thereof. 9 is a valve of the vacuum pump 6.

As the plasma discharge gas, a mixed gas of hydrogen gas and diluent gas is used. Hydrogen gas reduces and removes an oxide film by its strong reducing power. The diluent gas is added for safety. However, as described later, the diluent gas also has an effect of removing impurities on the substrate surface by colliding with molecules and ions on the substrate surface. As the diluent gas, an inert gas such as an Ar gas or a gas having a low reactivity such as a nitrogen gas is used.

Reference numeral 10 denotes a mounting portion made of an aluminum plate disposed at a front portion of the opening 2, and a lid member 11 of the opening 2 is attached to a rear portion thereof. The lid member 11 is supported by a bracket 14 erected on the nut 12. Reference numeral 13 denotes a feed screw into which the nut portion 12 is screwed, and reference numeral 15 denotes a drive motor.
Is driven, the nut portion 12 moves in the Y direction along the feed screw 13, and the mounting portion 10 enters and exits the casing 1 through the opening 2. That is, nut 12, feed screw 13, motor
Reference numerals 15 and the like denote forward / backward retreating means for moving the mounting portion 10 forward and backward with respect to the casing 1 so as to move the mounting portion 10 into and out of the casing 1 through the opening 2. Further, the lid member 11 moves integrally with the placing portion 10 and opens and closes the opening 2.

In FIG. 1, reference numerals 17 and 18 denote conveyors arranged in a direction intersecting the mounting portion 10 with the mounting portion 10 interposed therebetween. Is conveyed in the X direction that intersects the Y direction that is the moving direction of. 19 is the substrate 20
Is a stopper for stopping the operation.

2 and 4, reference numeral 21 denotes a transfer means for the substrate 20, which is provided between the conveyor 17 and the mounting portion 10 and between the conveyor 17 and the mounting portion 10.
And the conveyor 18 reciprocate in the X direction, and suck and transfer the substrate 20 to the suction pad 22. The substrate 20 is ceramic,
It is formed of glass, glass epoxy, or the like, and a circuit pattern is formed on its surface. The circuit pattern is formed of a copper foil or the like, and generates an oxide film when exposed to air.

This plasma cleaning apparatus has the above configuration, and the operation will be described next.

The substrate 20 transported by the conveyor 17 hits the stopper 19 and stops. Then, the transfer unit 21 sucks up the substrate 20 to take it up and transfers it to the mounting unit 10.
At this time, the mounting unit 10 is driven by the motor 15,
The sheet is pitch-fed toward the casing 1 and enters the casing 1 from the opening 2. In synchronization with the pitch feeding, the transfer means 21 reciprocates between the conveyor 17 and the mounting section 10 to transfer the substrate 20. By transferring the substrate 20 to the receiver 10, the substrates 20 are mounted on the receiver 10 in order one by one.

The lid member 11 closes the opening 2 in a state in which the transfer of the large number of substrates 20 to the mounting portion 10 is completed and the mounting portion 10 has completely entered the casing 1 in this manner (see FIG. (See the chain line in FIG. 1).

Next, the vacuum pump 6 is operated, the pressure in the casing 1 is reduced, a mixed gas of hydrogen gas and a diluent gas is supplied into the casing 1, and then a high-frequency AC voltage is applied to the electrode unit 3, whereby plasma is generated. Occur. At this time, part of the mixed gas is ionized, and the oxide film on the surface of the substrate 20 is reduced and removed by hydrogen gas molecules and ionized hydrogen ions. Ar gas molecules, ionized Ar +,
The minus electrons move violently at high speed in the casing 1 and collide with the surface of the substrate 20 to remove impurities attached to the surface. The removed impurities are sucked by the vacuum pump 6.
Examples of such impurities include hand grease adhered by an operator handling the substrate 20 and gasified oil floating in the air.

After removing the oxide film and impurities in this manner, the valve 9 of the vacuum pump 6 is closed and the valve 7 is opened to return the inside of the casing 1 to normal pressure. Next, the mounting portion 10 is pitch-fed in the direction opposite to the previous direction and is pulled out of the casing 1. At this time, in synchronization with the pitch feed, the transfer means 21 reciprocates between the placement unit 10 and the conveyor 18, transfers the substrate 20 to the conveyor 18, and transports the substrate 20 to the next step.

As described above, the present means performs the transfer of the substrate 20 to the mounting portion 10 and the unloading of the substrate 20 while the mounting portion 10 is pitch-fed in the Y direction and put in and out of the casing 1. Therefore, the workability is extremely good, and since the opening 2 can be opened and closed by the lid member 11 while the loading / unloading section 10 is being taken in and out, there is an advantage such as easy operation management. The object to be cleaned may be a wafer, or may be applied to a means for improving wettability by removing an oxide film on the surface of solder particles, which is a material for cream solder.

(Effects of the Invention) As described above, according to the present invention, the cleaning target is transferred to the mounting portion by the transfer means while the mounting portion is inserted into the casing from the opening, so that the cleaning target is moved. When the transfer to the mounting portion is completed and the mounting portion completely enters the casing, the opening is automatically and reliably closed by the lid member integrated with the mounting portion, so that a large number of It is possible to collectively perform the plasma cleaning processing of the individual cleaning objects with good workability.

[Brief description of the drawings]

1 shows an embodiment of the present invention. FIG. 1 is a plan view of a plasma cleaning apparatus, FIG. 2 is a side view, and FIG.
The figure is a sectional view, and FIG. 4 is a side view during transfer. DESCRIPTION OF SYMBOLS 1 ... Casing 2 ... Opening 3 ... Electrode part 6 ... Vacuum pump 10,12,13 ... Accessing means 20 ... Body to be cleaned

Claims (1)

(57) [Claims] 1. A casing to which a gas for plasma discharge is supplied, an electrode section for applying a high voltage to generate plasma inside the casing, a vacuum pump for sucking a gas inside the casing, and a casing for the casing A plasma cleaning apparatus using a mixed gas of a hydrogen gas and a diluent gas as the plasma discharge gas, comprising: The taking-out means,
A mounting portion for mounting a plurality of the objects to be cleaned, a lid member attached to the rear of the mounting portion, and the mounting portion is moved forward and backward with respect to the casing, and the mounting portion is A conveyor configured to advance and retreat from the opening into and out of the casing, and to convey the object to be cleaned to the mounting unit; and to deliver the object to be cleaned conveyed by the conveyor to the mounting unit. Means for moving the object to be cleaned, which has been conveyed by the conveyor by the transfer means, sequentially onto the mounting part, while allowing the mounting part to enter the casing from the opening by the advance and retreat means. The plasma cleaning apparatus is characterized in that the cover member closes the opening in a state where the transfer is completed and the mounting portion has completely entered the casing.