JPH0533139A - Method for attaching and detaching wafer to and from wafer holder - Google Patents

Abstract

PURPOSE:To stably attach and detach a wafer to and from a wafer holder used in a film forming device, etc., with tight adhesion without depositing dust on the wafer. CONSTITUTION:A film 8a contg. a magnetic substance is formed on the rear of a wafer 7 to be treated, then one magnetic charge is induced by an electromagnet 11 embedded in a wafer holder 10 consisting of a nonmagnetic material to magnetically fix the wafer 7 to the wafer carrying surface of the holder 10, and the wafer 7 is treated and then detached from the wafer carrying surface by inducing an opposing magnetic charge with the electromagnet 11.

Description

Detailed Description of the Invention

(Table of contents) ・ Industrial applications ・ Conventional technology (Fig. 6) ・ Problems to be solved by the invention ・ Means for solving problems ・ Action ·Example (1) First embodiment (FIGS. 1 and 2) (2) Second and third embodiments (FIGS. 3, 4, and 5) ·The invention's effect

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for holding a wafer, and more particularly to a method for attaching / detaching a wafer to / from a wafer holder used in a film forming apparatus or the like.

[0003]

2. Description of the Related Art Conventionally, in a film forming apparatus such as a CVD apparatus, a typical method for holding a wafer on which a film is formed is as shown below. That is, (1) a method of leaning a wafer by leaning it against a wall and holding it obliquely, (2) physically fixing the peripheral portion of the wafer 3 with a claw 2 formed on the wafer mounting surface of the wafer holding table 1 A method of holding the wafer on the wafer mounting surface of the holder (FIG. 6A), (3) Applying a DC voltage supplied from a DC power supply 6 to the electrodes embedded in the wafer holder 4, thereby attracting the Coulomb There is an electrostatic chuck method (FIG. 6B) in which the wafer 3 is held on the wafer mounting surface of the wafer holding table 4 by utilizing the.

Among the above wafer holding methods, (2),
The method (3) is capable of holding the wafer with the film forming surface facing downward, that is, so-called face-down holding, and is therefore an effective method for preventing dust from adhering during film formation.

[0005]

Each of the above methods has the following problems. That is, (1) in the method of leaning a wafer by leaning it against a wall and holding it obliquely, the holding itself is unstable and the wafer cannot be rotated because uniform processing such as film formation is performed. . (2) Further, in the method of physically holding the peripheral portion of the wafer 3 with the wafer holder with the claw 2 shown in FIG. 6A, the portion of the wafer 3 that is pressed against the wafer mounting surface by the claw 2. Is in sufficient contact with the wafer mounting surface, but the other portions of the wafer 3 are not sufficiently in contact with the wafer mounting surface, and, for example, the bias for ionizing the reaction gas is not uniformly applied to the wafer 3. Therefore, the film thickness of the film formed on the surface of the wafer 3 is not uniform. (3) Further, in the electrostatic chuck method shown in FIG. 6B in which the wafer 3 is held by using the Coulomb attractive force, the wafer 3
When dust or the like floats around the periphery of the wafer, the dust electrostatically adheres to the surface of the wafer 3 and a film is formed as it is, which leads to the occurrence of defects in the formed film.

The present invention has been made in view of the above conventional problems, and it is possible to hold a wafer on a wafer holder with stability and good adhesion and prevent dust from adhering to the wafer. An object of the present invention is to provide a method of attaching and detaching a wafer to and from a holder.

[0007]

The above-mentioned problems are as follows. First, after forming a film containing a magnetic material on the back surface of a wafer to be processed,
An electromagnet embedded inside a wafer holder made of a non-magnetic material generates a magnetic field that attracts the wafer by interaction with the film containing the magnetic material, and fixes the wafer on the wafer mounting surface. And a second method for holding a wafer on a wafer holder, characterized in that
A magnetic field for fixing the wafer on the wafer mounting surface of the wafer holder by the wafer holding method according to the first aspect of the present invention to process the wafer, and then separating the wafer by interaction with the film containing the magnetic substance. Is generated by the electromagnet, or the magnetic field from the electromagnet is extinguished, and the wafer is detached from the wafer mounting surface.
Thirdly, after forming a film containing a magnetic material on the back surface of the wafer to be processed, a heater made of a magnetic material is embedded,
On the wafer mounting surface of the wafer holder made of non-magnetic material,
A wafer holding method for a wafer holder, characterized in that the wafer is attracted and fixed by a magnetic interaction between the film containing the magnetic material and the heater. Fourthly, a wafer to be processed After a film containing a magnetic substance is formed on the back surface of the wafer, a heater is embedded and a wafer holding surface of a wafer holding table made of a magnetic material has a film containing the magnetic substance and the wafer mounting surface. A wafer holding method for a wafer holder, characterized in that the wafer is attracted and fixed by magnetic interaction with a mounting surface, and the wafer according to the fifth, third or fourth invention is achieved. After the wafer is magnetically fixed to the wafer mounting surface of the wafer holder by the holding method to process the wafer, the wafer holder and the wafer are heated by the heater to weaken the magnetization and the wafer mounting surface. Is achieved by the wafer attaching and detaching method of the wafer holder, characterized in that disengaging the Luo wafer.

[0008]

In the method for holding a wafer on the wafer holder according to the present invention, firstly, a film containing a magnetic material is formed on the back surface of the wafer, and a magnetic field for attracting the wafer is generated by interaction with the film containing the magnetic material. The wafer is fixed to the wafer mounting surface by being generated by an electromagnet embedded in the wafer holder.

Secondly, due to the magnetic interaction between the film containing a magnetic material and the heater on the wafer mounting surface of the wafer holder made of a non-magnetic material in which the heater made of a magnetic material is embedded. The wafer is adsorbed and fixed.

Thirdly, on the wafer mounting surface of the wafer holder in which the heater is embedded and the wafer mounting surface is made of a magnetic material, the film containing the magnetic material and the wafer mounting surface are magnetically interacted with each other. The action attracts and fixes the wafer.

Therefore, (1) the wafer holding is stable like an electrostatic chuck, and the wafer holder can be rotated to rotate. (2) The back surface of the wafer can evenly contact the wafer mounting surface. (3) Since magnetic force is used to fix the wafer, it is possible to prevent dust and the like from electrostatically adhering to the wafer surface.

Further, while maintaining the advantages of the above holding method, the wafer placed on the wafer holding table is detached from the wafer placing surface. That is, first, the magnetic field that causes the wafer to be separated by the interaction with the film containing the magnetic substance on the back surface of the wafer is generated by the electromagnet, or the magnetic field from the electromagnet is extinguished, so that the wafer is separated from the wafer mounting surface. I am letting you.

Secondly, the heater is used to heat the wafer holder and the wafer to weaken the magnetization and separate the wafer from the wafer mounting surface.

Therefore, the wafer can be easily detached from the wafer holder.

[0015]

【Example】

(1) First Embodiment FIGS. 1 (a) to 1 (c), 2 (d) and 2 (e) are sectional views for explaining a wafer attaching / detaching method of the first embodiment of the present invention. An example applied when forming a film on the wafer surface by the atmospheric pressure CVD method is shown.

First, a ferrite / yttrium powder as a magnetic material and an epoxy resin are mixed with an organic solvent to prepare a viscous solution, and the solution 8 containing the magnetic material is formed on the back surface of the wafer 7 on which a film is to be formed. After dripping on (Fig. 1
(A)), is applied by a spin coating method (FIG. 1 (a)), and is further dried to form a film 8a containing a magnetic material.

Next, a current is applied to the coil 12a of the electromagnet 11 embedded in the wafer holder 10 made of ceramic, and a magnetic charge (for example, S) such that the film 8a containing the magnetic substance on the back surface of the wafer 7 is attracted is applied to the electromagnet 10. Of the core 7b, the wafer 7 is held on the wafer mounting surface of the wafer holder 10, and is set in a chamber (not shown) so that the film forming surface of the surface of the wafer 7 faces downward (face down). (FIG. 1 (c)).

Next, while the wafer holder 10 is being rotated, a reaction gas is introduced into the chamber to form a film 13 on the surface of the wafer 7 so that the film is uniformly formed (see FIG. 2 (d)). )).

Next, after forming the film 13, the electromagnet 11 is formed.
The current 12 is applied to the coil 12a of the electromagnet 11 in the opposite direction to that of the case where the wafer 7 is held, and the opposite magnetic charge (for example, N) is applied to the core 12b of the electromagnet 11.
Then, the wafer 7 is detached from the wafer holder 10 (FIG. 2E). It is also possible to remove the magnetic field by cutting off the current flowing through the coil 12a of the electromagnet 11 to separate the wafer 7 from the wafer holder 10.

In this way, the film formation is completed.

As described above, in the wafer holding method for the wafer holder according to the first embodiment of the present invention, a current is caused to flow through the coil 12a of the electromagnet 11 embedded in the wafer holding table 10 to cause the core of the electromagnet 11 to move. A magnetic charge is induced in 12b, and the wafer 7 is attracted and fixed to the wafer mounting surface by the interaction of the magnetic charge in the film 8a containing the magnetic substance on the back surface of the wafer 7 with the magnetic charge.

Therefore, (1) the wafer holding is stable like an electrostatic chuck, and the wafer holder can be rotated to rotate. (2) The back surface of the wafer 7 can evenly contact the wafer mounting surface. (3) Since magnetic force is used to fix the wafer 7, it is possible to prevent dust and the like from electrostatically adhering to the surface of the wafer 7.

In addition, a reverse current is applied to the coil of the electromagnet 11 to induce a reverse magnetic charge in the core 12b of the electromagnet 11, or the current applied to the coil of the electromagnet 11 is cut off to eliminate the magnetic field. As a result, the wafer 7 is detached from the wafer mounting surface, so that the wafer 7 can be easily detached from the wafer holder.

(2) Second and Third Embodiments FIG.
FIGS. 4C, 4D, and 4E are views for explaining a method of attaching / detaching a wafer to / from a wafer holder according to the second embodiment of the present invention. An example applied when a film is formed on the wafer surface by the CVD method is shown.

First, a ferrite / yttrium powder as a magnetic material and an epoxy resin are mixed with an organic solvent to prepare a viscous solution, and the solution 8 containing the magnetic material is applied to the back surface of the wafer 7 on which a film is to be formed. After dropping (Fig. 3
(A)), coating by spin coating method and further drying to form a film 8a containing a magnetic material (FIG. 3 (b)).

Then, nichrome (N
The wafer 7 is mounted on the wafer mounting surface of the wafer holding base 14 made of ceramic as a non-magnetic material in which the heater 15 made of iCr) is embedded. At this time, a magnetic charge (for example, S) is induced in the heater 15 by the magnetic substance in the film 8a containing the magnetic substance on the back surface of the wafer, and the wafer 7 is magnetically attracted and fixed to the wafer mounting surface of the wafer holding table 14. It Further, the wafer 7 is set in a chamber (not shown) so that the film forming surface of the wafer 7 faces downward (face down) (FIG. 3C).

Then, while rotating the wafer holder, a reaction gas is introduced into the chamber to form a film 13 on the surface of the wafer 7 so that the film can be uniformly formed (FIG. 4).
(D)).

Next, after forming the film, an electric current is supplied to the heater 15 to heat the heater 15 and the wafer 7. as a result,
The magnetic force of the magnetic substance in the film 8 a containing the magnetic substance on the back surface of the wafer 7 and the magnetization of the heater 15 are weakened, and the wafer 7 can be easily detached from the wafer holding table 14.

When the wafer 7 is separated from the wafer holder in this way, film formation is completed (FIG. 4 (e)).

As described above, in the wafer holding method for the wafer holder according to the second embodiment of the present invention, the magnetic material in the film 8a containing the magnetic material formed on the back surface of the wafer 7 is made of the magnetic material. By inducing a magnetic charge in the heater 15 consisting of, the wafer 7 is magnetically attracted and fixed to the wafer mounting surface of the wafer holder 14 in which the heater 15 is embedded.

Therefore, as in the case of the first embodiment, (1) the wafer holding is stable, and the rotating operation is possible by the rotation of the wafer holder. (2) The back surface of the wafer 7 can evenly contact the wafer mounting surface. (3) Since magnetic force is used to fix the wafer 7, it is possible to prevent dust and the like from electrostatically adhering to the surface of the wafer 7.

Further, since the heater 15 and the wafer 7 are heated by supplying an electric current to the heater 15 to weaken the magnetization and detach the wafer 7 from the wafer mounting surface, the wafer 7 is easily detached from the wafer holder. Can be made.

In the second embodiment, the wafer holding base 14 in which the heater 15 made of a magnetic material is embedded and the wafer mounting surface is made of a non-magnetic material is used, but the third embodiment is used. As shown in FIG. 5, the heater 17 made of a non-magnetic material or the heater 15 made of a magnetic material.
It is also possible to use the wafer holding table 16 in which the wafer mounting surface 16a is embedded and the wafer mounting surface 16a is made of a magnetic material. As a result, the film 8a containing the magnetic material formed on the back surface of the wafer 7
A magnetic substance is induced in the wafer mounting surface 16a or the heater 17 by the magnetic substance therein, and the wafer 7 is magnetically mounted on the wafer mounting surface 16a.
Can be adsorbed and fixed. Further, the wafer mounting surface 16
It is possible to easily separate the wafer 7 from the wafer holder 16 by heating the a and the wafer 7 by the heater 17, or by heating the heater 17 itself.

Further, although ferrite / yttrium powder is used as the magnetic substance in the film including the magnetic substance on the back surface of the wafer 7, other magnetic substances can be used.

[0035]

As described above, in the method of attaching and detaching a wafer to and from the wafer holder according to the present invention, firstly, a film containing a magnetic material formed on the back surface of the wafer by the electromagnet embedded in the wafer holder. A magnetic field for adsorbing the wafer is generated by the interaction with and to fix the wafer on the wafer mounting surface. Further, by causing the electromagnet to generate a magnetic field that causes the wafer to be detached by the interaction with the film containing the magnetic substance on the back surface of the wafer or extinguishing the magnetic field from the electromagnet, the wafer held as described above is mounted on the wafer. It is detached from the surface.

Secondly, a wafer having a film containing a magnetic material formed on its back surface is provided on the wafer mounting surface of a wafer holder in which a heater made of a magnetic material is embedded. It is adsorbed and fixed by magnetic interaction.
Alternatively, a wafer having a film containing a magnetic substance formed on the back surface is magnetically separated from the film containing the magnetic substance and the wafer mounting face on the wafer mounting face of the wafer holding table whose wafer mounting face is made of a magnetic material. It is adsorbed and fixed by various interactions. Further, by heating the wafer holder and the wafer with a heater to weaken the magnetization, the wafer held as described above is separated from the wafer mounting surface.

Therefore, (1) the wafer is held stably, and the wafer holder can be rotated to rotate. (2) The back surface of the wafer can evenly contact the wafer mounting surface. (3) Since magnetic force is used to fix the wafer, it is possible to prevent dust and the like from electrostatically adhering to the wafer surface.

Further, the wafer mounted on the wafer holder can be easily detached from the wafer holder while ensuring the advantages of the above holding method.

[Brief description of drawings]

FIG. 1 is a diagram (No. 1) for explaining a method of attaching and detaching a wafer to and from a wafer holder according to the first embodiment of the present invention.

FIG. 2 is a diagram (No. 2) for explaining the method of attaching and detaching a wafer to and from the wafer holder according to the first embodiment of the present invention.

FIG. 3 is a diagram (No. 1) for explaining a method of attaching / detaching a wafer to / from a wafer holder according to the second embodiment of the present invention.

FIG. 4 is a diagram (No. 2) explaining a method of attaching and detaching a wafer to and from the wafer holder according to the second embodiment of the present invention.

FIG. 5 is a diagram illustrating a method of attaching / detaching a wafer to / from a wafer holder according to a third embodiment of the present invention.

FIG. 6 is a diagram illustrating a method of attaching and detaching a wafer to and from a conventional wafer holder.

[Explanation of symbols]

1, 4, 10, 14, 16 Wafer holder, 2 nails, 3,7 wafers, 5 electrodes, 6 DC power supply, 8 Solution containing magnetic material, 8a a film containing a magnetic material, 9 Spinner, 11 electromagnets, 12a coil, 12b core, 13 membranes, 15,17 heater, 16a Wafer mounting surface.

Claims (5)

[Claims] 1. A film containing a magnetic material on the back surface of the wafer is formed by an electromagnet embedded inside a wafer holder made of a non-magnetic material after forming a film containing a magnetic material on the back surface of the wafer to be processed. A method for holding a wafer on a wafer holder, characterized in that a magnetic field for attracting the wafer is generated by an interaction with the wafer holder to fix the wafer on the wafer mounting surface. 2. The wafer holding method according to claim 1, wherein the wafer is fixed on the wafer mounting surface of the wafer holding table to process the wafer, and then the wafer is removed by an interaction with a film containing the magnetic material. A method of attaching / detaching a wafer to / from a wafer holder, wherein a magnetic field to be detached is generated by the electromagnet or a magnetic field from the electromagnet is extinguished to detach the wafer from the wafer mounting surface. 3. After forming a film containing a magnetic material on the back surface of a wafer to be processed, a wafer holding surface made of a non-magnetic material, in which a heater made of a magnetic material is embedded, is provided on the wafer mounting surface. A method of holding a wafer on a wafer holder, wherein the wafer is attracted and fixed by a magnetic interaction between a film containing a magnetic material and the heater. 4. After forming a film containing a magnetic material on the back surface of a wafer to be processed, a heater is embedded, and the wafer mounting surface of a wafer holding table made of a magnetic material is attached to the wafer mounting surface. A method for holding a wafer on a wafer holder, wherein the wafer is attracted and fixed by a magnetic interaction between a film containing a magnetic material and the wafer mounting surface. 5. The wafer holding base and the wafer after the wafer is magnetically fixed to the wafer mounting surface of the wafer holding base by the wafer holding method according to claim 3 or 4 to process the wafer. A method of attaching and detaching a wafer to and from a wafer holder, wherein the magnetization is weakened by heating the wafer by the heater, and the wafer is detached from the wafer mounting surface.