KR20050099879A - Bake apparatus used in manufacturing semiconductor devices - Google Patents

Abstract

The present invention relates to a baking device, wherein the device has a heating plate disposed in the chamber. The heating plate has a seating portion on which the wafer is placed and a ring-shaped auxiliary portion projecting upward from the edge of the seating portion. The controllable heaters are disposed in the seating portion and the auxiliary portion, respectively.

Description

BAKE APPARATUS USED IN MANUFACTURING SEMICONDUCTOR DEVICES

The present invention relates to a device used for manufacturing a semiconductor device, and more particularly, to a baking device for performing a step of heating the semiconductor substrate to a constant temperature.

Recently, as semiconductor devices have been highly integrated, the chip unit area has been reduced and the circuit dimension has been reduced, so the importance of a photolithography process for implementing a pattern on a wafer has emerged. The photolithography process consists of various processes such as coating process, exposure process, developing process, and baking process, among which baking process heats the wafer to a certain temperature, and moisture adsorbed onto the wafer before applying the photoresist. There is a pre-baking process for removing the photoresist, a soft bake process for alleviating the shear stress generated during photoresist coating, and a post-exposure bake process for restoring the instability of the chemical structure of the post-exposure exposure site.

A general apparatus for performing the baking process described above has a heating plate in which a heater is installed. The heating plate has a flat upper surface, and a heating wire formed in a coil shape is mainly used as a heater. During the process, the heating plate on which the wafer is placed is surrounded by a chamber and sealed from the outside. If the wafer is not heated uniformly throughout the baking process, there is a problem that the line width formed on the wafer is different depending on the area of the wafer. To this end, attempts have been made to diversify the arrangement of heaters so that the entire upper surface of the heating plate is uniformly heated. However, even though the heating plate is maintained at a uniform temperature during the process, the flow of hot air (radiation heat, conduction heat, convection heat) is different according to the position of each wafer area, so the wafer is not heated uniformly as a whole. The line width is different depending on the center region and the edge region of the wafer.

An object of the present invention is to provide a baking apparatus capable of minimizing the line width difference according to the area of the wafer by providing uniform heat throughout the wafer.

In order to achieve the above object, the baking apparatus of the present invention includes a process chamber and a heating plate disposed therein to heat the semiconductor substrate, wherein the heating plate receives heat from the heater unit. The heating plate has a seating portion and an auxiliary portion. The seat portion receives heat from a seat heater disposed therein as a portion where the semiconductor substrate is placed. The auxiliary part is disposed on the seating part so as to be positioned around the semiconductor substrate placed on the seating part, and receives heat from the auxiliary part heater disposed therein.

The auxiliary part may be formed in an annular ring shape to surround the circumference of the semiconductor substrate, and may be disposed perpendicularly to the seating part. In addition, the seat heater and the auxiliary heater is preferably controlled independently.

According to the present invention, the hot air flow is formed in the upper portion of the wafer center and the upper edge of the wafer to reduce the difference in line width in the entire region of the wafer, and the heat provided to the wafer edge region can be effectively controlled.

Hereinafter, an embodiment of the present invention will be described in more detail with reference to FIGS. 1 to 2. The embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Therefore, the shape of the elements in the drawings are exaggerated to emphasize a clearer description.

The present invention relates to a baking apparatus 1 that performs a step of heating a wafer to a constant temperature. The baking apparatus may be a baking apparatus used for a photolithography process or a baking apparatus used for wafer heating in other processes.

1 is a view schematically showing a baking device 1 according to a preferred embodiment of the present invention. Referring to FIG. 1, the baking device 1 includes a chamber 100, a hot plate 200, a lift pin assembly 300, and a heater 400. ) The chamber 100 has a body 120 and a cover 140 to provide a space in which the baking process is performed. The body 120 has a cylindrical shape with an open top, and the cover 140 opens and closes the open top of the body. The driving unit 142 is coupled to the cover 140 to move the cover 140 up and down or left and right. When the wafer is transferred to / from the chamber 100, the lid 140 is separated from the body 120 so that the top of the body 120 is opened, and a baking process is performed on the wafer within the chamber 100. When proceeding, the cover 140 is coupled to the body 120 to seal the inside of the chamber 100 from the outside.

In the lower portion of the chamber 100, a heating plate 200 supporting the wafer and heating the wafer is disposed. Referring to FIG. 2, which is a plan view of the heating plate 200, the heating plate 200 has a seating portion 220, an auxiliary portion 240, and a guide block 260. The seating portion 220 has a disc shape having a generally flat top surface. During the process, the heating plate 200 is maintained at a high temperature by the heater unit 400 to be described later. Although not shown, spacers may be installed to protrude from the upper surface of the mounting portion 220 to prevent the wafer from directly contacting the high temperature mounting portion 220 during the process. The guide block 260 guides the wafer to be placed in position on the heating plate 200 and is installed on the seating portion 220. The guide blocks 260 may be arranged approximately equally spaced so that they provide space for placing the wafer thereon.

When the seating unit 220 is heated to a high temperature by the heater unit 400, different hot air flows (radiation heat, conduction heat, convection heat, etc.) are formed in the upper portion of the wafer depending on the region. That is, the hot air flows formed on the central region of the wafer and the upper edge region of the wafer are different from each other. As a result, the line width of the pattern formed on the wafer varies depending on the area of the wafer. The auxiliary part 240 allows the hot air flow over the edge region of the wafer to be the same as the hot air flow over the central region of the wafer. The auxiliary part 240 is disposed on an edge of the seating part 220 to surround the wafer placed on the seating part 220 and has an annular ring shape. The auxiliary part 240 may be manufactured integrally with the seating part 220 to protrude from the seating part 220. Optionally, after the auxiliary part 240 and the seating part 220 are manufactured, the auxiliary part 240 may be installed on the seating part 220. The auxiliary part 240 is disposed vertically from the seating part 220. Optionally, the auxiliary unit 240 may simultaneously perform the function of the guide block 260 without separately installing the guide block 260.

The lift pin assembly 300 positions the wafer transferred by the arm into the chamber 100 onto the seating portion 220. Referring again to FIG. 1, the lift pin assembly 300 has lift pins 320, a support plate 340, and a lift 360. The lift pins 320 are portions that take over a wafer from an arm (not shown) and are coupled on the support plate 340 in an equilateral triangle arrangement. A lifting part 360, such as a hydraulic cylinder, is connected to the lower part of the support plate 340, and the support plate 340 is vertically moved up and down by the lifting part 360. Each lift pin 320 is inserted into a hole 222 formed to penetrate the seat 220 up and down, and is moved up and down along the hole 222. In the state where the lift pins 320 protrude above the seat 220, the wafer transferred to the seat 220 above the arm is turned over to the lift pins 320. When the lift pins 320 are moved below the upper surface of the seating part 220 along the hole formed in the seating part 220, the wafer is placed on the seating part 220.

The heater unit 400 is disposed inside the heating plate 200 and provides heat to the heating plate 200. The cover of the chamber 100 is provided with a sensor 520 for measuring the temperature inside the chamber 100 during the process, the control unit 500 may control the heater unit 400 in consideration of the temperature measured from the sensor. . The heater unit 400 is disposed in the seating unit 220 to provide heat to the seating unit 220 and the auxiliary heater unit disposed in the auxiliary unit 240 to provide heat to the auxiliary unit 240 ( 440). For example, the seat heater 420 may be a hot wire having a shape in which the radius gradually increases from the center to the outside. The heating wires may be disposed in accordance with the regions and may be controlled independently of each other to provide the same heat to the center portion and the edge portion of the seating portion 220. Optionally, the heating wires may have different radiuses depending on the regions, and may be densified toward the edges.

The auxiliary heater 440 allows the heating of the wafer edge to be precisely controlled. The auxiliary heater 440 is controlled independently of the seat heater 420. Optionally, the auxiliary heater 440 may extend from the seat heater 420 and be controlled with the seat heater 420. The auxiliary part 240 heated by the auxiliary heater 440 may provide heat to directly heat the edge of the wafer, or shape the hot air flow formed on the edge of the wafer. As described above, when the auxiliary part 240 is formed of a ring, the auxiliary heater 440 may be formed of a circular hot wire disposed in the ring along the ring or may be formed of a rod-shaped hot wire evenly spaced at regular intervals. Can be. In addition, the auxiliary part 240 may be spaced apart from each other at equal intervals on the edge of the seating part 220, in which case the auxiliary heater 440 is a rod-shaped hot wire disposed inside each auxiliary part 240 Can be formed.

According to the present invention, since the heating plate includes an auxiliary portion projecting upward from the edge of the seating portion on which the wafer is seated, hot air flow is formed on the upper portion of the center of the wafer and on the upper edge portion of the wafer, and the heating plate is formed on the wafer during the baking process. There is an effect that the line width of the formed pattern is the same.

In addition, according to the present invention, since the heater is independently controlled in the auxiliary portion disposed on the side of the wafer, there is an effect that the heating of the wafer edge portion can be more precisely adjusted.

1 shows schematically a baking apparatus according to a preferred embodiment of the present invention; And

FIG. 2 is a plan view of the heating plate of FIG. 1.

Explanation of symbols on the main parts of the drawings

100 chamber 200 heating plate

220: seating part 240: auxiliary part

260: guide block 300: lift pin assembly

400: heater 420: seat heater

440: auxiliary heater 500: control unit

Claims (5)

In the baking apparatus which heats a semiconductor substrate, A process chamber; A heating plate disposed in the process chamber to heat the semiconductor substrate; And Including a heater unit for providing heat to the heating plate, The heating plate has a seating portion on which the semiconductor substrate is placed and an auxiliary portion disposed on the seating portion so as to be positioned around the semiconductor substrate placed on the seating portion, And the heater part comprises a seat heater providing heat to the seating part and an auxiliary heater providing heat to the auxiliary part. The method of claim 1, The seating unit heater and the auxiliary heater is a baking device, characterized in that independently controlled. The method of claim 1, The seat heater is a heating wire disposed in the seat, The auxiliary heater is a baking device, characterized in that the hot wire inserted into the auxiliary portion. The method of claim 1, And the auxiliary part is formed in a ring shape so as to surround a circumference of the semiconductor substrate. The method of claim 4, wherein And the auxiliary portion is disposed perpendicularly to the seating portion.