KR20080046436A - Apparatus for baking a layer on a substrate - Google Patents

Abstract

A baking apparatus is provided to maintain exhaust pressure at a constant level and consistently transfer heat over the surface of a substrate by forming a plurality of exhaust portions for discharging process byproducts. A baking apparatus(100) comprises a stage(112), a cover(122), a plurality of exhaust lines(136,138), a plurality of exhaust adjusters(134), a pump(140), a purge gas supply unit(142), and a shower plate. The stage holds a substrate(W) having a layer formed thereon, comprising a heater for baking the layer, wherein a plurality of holes(132) connecting with the exhaust lines are formed on the stage, arranged in regular intervals along the periphery of the stage. The cover is disposed on the stage and defines a space for baking the layer. The exhaust lines is connected to the stage, for discharging gas containing process byproducts produced during a baking process. The exhaust adjusters, each in connection with the exhaust line, are configured to adjust the amount of gas exhausted via the exhaust lines at constant level. The pump is connected to the exhaust lines. The purge gas supply unit is connected to the cover to supply purge gas to the space. The shower plate is assembled to the cover to consistently supply the purge gas to the space.

Description

Apparatus for baking a layer on a substrate}

1 is a schematic plan view for explaining an exhaust of a baking apparatus according to the prior art.

2 is a schematic cross-sectional view illustrating a baking apparatus according to an embodiment of the present invention.

FIG. 3 is a schematic plan view for describing the exhaust unit illustrated in FIG. 2.

Explanation of symbols on the main parts of the drawings

100: baking device 112: stage

130: exhaust part 132: exhaust hole

134: exhaust control unit 136, 138: first and second exhaust line

140: pump 142: purge gas supply unit

The present invention relates to a baking apparatus, and more particularly, to an apparatus for baking a photoresist coated on a semiconductor substrate, such as a silicon wafer.

In general, a semiconductor device includes a fabrication (fab) process for forming an electrical circuit on a silicon wafer used as a semiconductor substrate, and an electrical die sorting (EDS) process for inspecting electrical characteristics of the semiconductor devices formed in the fabrication process. And a package process for encapsulating and individualizing the semiconductor devices with an epoxy resin, respectively.

The fab process includes various unit processes, and among the unit processes, the photolithography process includes forming a photoresist pattern used in an etching process for forming a film formed on a semiconductor substrate through a deposition process into a pattern having electrical characteristics. To form a phase.

The photolithography process includes a photoresist coating process for forming a photoresist film on a semiconductor substrate, volatilization of a solvent contained in the photoresist film, and a soft bake for solidification of the photoresist film. An exposure process for transferring a photo mask pattern onto the photoresist film solidified through the soft bake process, and resolution due to scattering of light irradiated onto the semiconductor substrate during the exposure process. A post exposure bake process to prevent degradation, a development process for forming a photoresist pattern by partially removing the exposed photoresist film, and the developed photoresist It may include a hard bake process for strengthening the pattern.

Such baking processes may be performed by heating the semiconductor substrate. For example, the soft bake process may be performed by heating the semiconductor substrate at about 80 ° C. to 120 ° C., and the PEB process may be performed by heating the semiconductor substrate at about 80 ° C. to 150 ° C. The hard bake process may be performed by heating the semiconductor substrate to about 150 ° C to 200 ° C.

The conventional baking apparatus for performing the baking process includes a bake stage for supporting a substrate and having a heater therein for baking a film formed on the substrate, and being disposed to be movable above the bake stage to bake the film. The cover may include a space, and an exhaust unit for discharging gas remaining in the space between the stage and the cover.

1 is a schematic plan view for explaining the exhaust 12 of the baking apparatus according to the prior art.

Referring to FIG. 1, the exhaust part 12 is disposed at an edge of the stage 10 for supporting the substrate W, and a space in which a bake process is performed on a fume generated during the bake process. Used to discharge from the outside. Specifically, the exhaust part 12 includes a hole 14 formed on the stage 10 for supporting the substrate W, a pump 16 providing exhaust pressure, and the exhaust pressure hole 14. And an exhaust line 18 for delivery.

However, the exhaust part 12 disposed as described above is disposed on both sides of the stage, so that the exhaust pressure delivered into the space may not be uniform. That is, when exhausting the fume through the exhaust part, a deviation of the exhaust pressure of the portion adjacent to the exhaust portion and the portion not adjacent to the exhaust portion occurs.

The baking process may depend on the temperature transferred from the stage 10 to the substrate W, and uniform heat may not be transferred to the entire surface of the substrate W due to the variation in the exhaust pressure. In addition, heat in the space may be exhausted together with the fume to lower the temperature in the space. As a result, local failure of the pattern formed after the baking process may occur.

An object of the present invention for solving the above problems is to provide a baking apparatus that can maintain a uniform temperature of the substrate during the baking process of the substrate.

In order to achieve the object of the present invention, the present invention supports a substrate on which a film is formed, and a cover having a built-in heater for baking the film and an upper portion of the stage, the cover defining a space for baking the film and the A plurality of exhaust lines connected to a stage and connected to the exhaust lines to discharge gas including process by-products generated during the baking process, and the flow rate of the gas exhausted through the exhaust lines And adjusting portions for constantly adjusting the flow rate.

According to one embodiment of the invention, the stage is formed with a plurality of holes in communication with the exhaust lines, the holes may be arranged at regular intervals along the edge of the stage.

According to an embodiment of the present invention, the pump may further include a pump connected to the exhaust lines, and the pump and the exhaust lines may be connected through a second exhaust line.

According to one embodiment of the invention, it is connected to the cover, may further include a purge gas supply unit for supplying a purge gas to the space, is coupled to the cover, uniformly supply the purge gas to the space It may further include a shower plate for.

The baking apparatus according to the present invention configured as described above has a plurality of exhaust parts for discharging the process by-products at regular intervals, thereby making the exhaust pressure in the space where the baking process is performed constant.

In addition, the exhaust pressure of the baking apparatus can be kept constant by the adjusting unit. In particular, process by-products such as fumes generated during the baking process may be properly exhausted according to the baking process step. Therefore, the baking process may be more stabilized by allowing uniform heat to be transferred to the entire surface of the substrate.

Hereinafter, a baking apparatus according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the following examples, and those skilled in the art may implement the present invention in various other forms without departing from the technical spirit of the present invention. In the accompanying drawings, the dimensions of the substrate, layer (film), region, opening, electrode, pattern or structure are shown to be larger than the actual for clarity of the invention. In the present invention, each layer (film), region, opening, electrode, pattern or structure is "on", "upper" or "bottom" of the substrate, each layer (film), region, electrode, opening or pattern. When referred to as being formed in, it means that each layer (film), region, electrode, opening, pattern or structure is directly formed on or below the substrate, each layer (film), region, opening or pattern, or Other layers (films), other regions, different electrodes, different patterns or other structures may additionally be formed on the substrate.

FIG. 2 is a schematic cross-sectional view illustrating a baking apparatus according to an exemplary embodiment of the present invention, and FIG. 3 is a schematic plan view illustrating the exhaust unit illustrated in FIG. 2.

2 and 3, the baking apparatus 100 according to an embodiment of the present invention includes a chamber 100, an exhaust unit 130, and a purge gas supply unit 142.

The baking device 110 having the above-described configuration is used to bake a film formed on the substrate W. As shown in FIG. For example, it may be used to bake a photosensitive resin film or a photosensitive resin pattern formed on a semiconductor substrate W such as a silicon wafer.

Specifically, the chamber 100 may have a circular cap shape. The chamber 100 supports a substrate W having a film formed therein, and heats the substrate W to bake the film. A stage 112 and a cover 122 defining a process space in which the baking process for the film is performed.

The stage 112 is disposed on the lower surface of the chamber 110, and the stage 112 serves to stably support the baking plate 114 for uniformly baking the substrate W. That is, the stage 112 may be disposed to surround the bake plate 114 at the outside of the bake plate 114.

At this time, the surface of the stage 112 is coated with Teflon so that the convection phenomenon does not occur inside the chamber 110 due to a temperature difference from the outside of the chamber 110, the inside of the chamber 110 Insulating layer may be formed to block the heat to be retained to the outside.

The baking plate 114 has a disk shape as a whole, and the substrate W is placed in the horizontal direction on the baking plate 114. A heating wire 116 is provided inside the baking plate 114 to heat the entire surface of the baking plate 114.

The heating wire 116 is provided in a concentric shape with respect to the center of the bake plate 114 and uniformly heat the baking plate 114, otherwise the heating wire 116 is in the form of a spiral, lattice, etc. It may be provided in various forms.

In addition, a temperature sensor 118 for detecting the temperature of the baking plate 114 is provided, and when the temperature detected by the temperature sensor 118 is lower or higher than the set temperature, the set temperature to be The hot wire 116 is driven.

In addition, a plurality of support pins 120 may be installed on an upper surface of the baking plate 114 to support the substrate W so as to be placed in a horizontal direction. The substrate W is disposed on the upper surfaces of the support pins 120 so that the substrate W does not directly contact the upper surface of the baking plate 114.

 The cover 122 may have the same circular cap shape as the chamber, and may function to seal the inside of the chamber 110 or open the inside of the chamber 110. The cover 122 is disposed to be movable above the stage 110 and may be opened and closed for loading and unloading of the substrate W. In addition, although not shown, the cover 122 may be connected to a driving unit for opening and closing. During the baking process, the cover 122 is lowered by the driving unit (not shown) to be coupled with the upper portion of the chamber 110, and the lower portion of the cover 122 has an inner portion where the baking process is performed. A sealing member 124 is mounted to seal the space from the outside.

The cover 122 is connected to a purge gas supply unit 142 for supplying a purge gas to a space where the baking process is performed. Specifically, the purge gas supply unit 142 is provided to supply a purge gas while the loading and unloading of the substrate W is performed, the purge gas supply unit 144 for supplying an inert gas such as nitrogen gas and It includes a purge gas supply line 146 for delivering the purge gas from the purge gas supply unit 144 into the space.

In addition, although not shown, the purge gas supply unit 142 may be provided with a heating unit for heating the purge gas supplied along the supply line 146 to a predetermined temperature required for the process to be supplied into the chamber 110. . Since the heating unit preheats the gas immediately before the purge gas is introduced into the chamber 110 and directly supplies the gas into the chamber 110, the heating part does not affect the temperature inside the process space while the baking process is performed. Do not.

The cover 122 is installed to be spaced apart from the gas supply plate 148 and the gas supply plate 148, which are connected to the gas supply line 146 and have a plurality of gas injection holes 124 formed in a central portion thereof. And a first buffer plate 126 having a plurality of holes and a second buffer plate 128 having a plurality of holes and installed to be spaced apart from the first buffer plate 126 by a predetermined interval.

The gas supply plate 148 has a plurality of gas inlets formed in the center of the circular plate so that nitrogen gas injected through the gas supply line 146 is injected. That is, nitrogen gas passing through the gas supply unit and the heating unit is injected into the gas inlet of the gas supply plate 148 through the gas supply line.

The first buffer plate 126 has a plurality of holes formed on the front surface of the circular plate. The hole is formed in a circular plate with a uniform diameter. Therefore, the nitrogen gas supplied from the gas supply plate 148 is uniformly dispersed in the inner space of the chamber 110.

The second buffer plate 128 is installed to be spaced apart from the first buffer plate 126 by a predetermined interval, and a plurality of holes are formed in the front surface of the circular plate. The plurality of holes become smaller in diameter from the center to the edge of the circular plate. Therefore, due to the nitrogen gas supplied from the gas supply plate 148 is injected a lot in the center portion to maintain a uniform temperature distribution of the substrate (W), the nitrogen gas injected in the center portion forms a lateral flow to the outer It is blown outward with the nitrogen gas supplied from the small hole.

The exhaust unit 130 is connected to the stage 110 to discharge a gas including a process by-product generated during the baking process, and includes an exhaust hole 132, an exhaust control unit 134, and a first gas. An exhaust line 136 and a second exhaust line 138.

The exhaust hole 132 provides exhaust pressure into the space and is disposed along an edge of the stage 112. Specifically, a plurality of exhaust holes 132 are arranged at regular intervals so that the distribution of exhaust pressure supplied in the space is uniform. A plurality of first exhaust lines 136 are connected to the exhaust hole 132 to discharge process byproducts to the outside of the chamber 110. The first exhaust lines 136 are formed downward from the upper surface of the stage 112 and branched from the second exhaust line 138 connected to the pump 140 for providing the exhaust pressure. . The number, location, arrangement relations of the exhaust holes 132 and the positions of the first exhaust line 136 and the second exhaust line 138 may be variously changed to the extent that the exhaust pressure may be maintained uniformly.

Exhaust control units 134 are provided on the first exhaust lines 136 to adjust the flow rate of the exhaust gas exhausted through the first exhaust lines 136 to a predetermined reference flow rate. The exhaust control unit 134 measures the flow rate of the exhaust gas and compares it with a reference flow rate. As a result of the comparison, when the flow rate is higher or lower than the preset flow rate, the first exhaust lines 136 are opened and closed. Also, although not shown, the exhaust control unit 134 may include a valve for opening and closing the first exhaust lines 136 according to the measured exhaust pressure. The exhaust unit 130 may accurately measure the flow conditions of the exhaust gas. The exhaust control unit 138 may adjust the exhaust pressure by measuring the temperature and pressure change rate of the gas.

As described above, the baking apparatus according to the embodiment of the present invention has a plurality of exhaust parts for discharging the process by-products, thereby making the exhaust pressure in the space where the baking process is performed constant. Thus, uniform heat is transferred to the entire surface of the substrate.

In addition, the exhaust pressure of the baking apparatus can be kept constant by the adjusting unit installed in the exhaust unit. In particular, by appropriately evacuating process by-products such as fumes generated during the baking process according to the baking process step, it is possible to minimize the occurrence of defects in the baking process by minimizing the occurrence of defects during the baking process.

While the foregoing has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

Claims (5)

A stage supporting a substrate on which a film is formed and having a heater built therein for baking the film; A cover disposed above the stage and defining a space for baking the film; A plurality of exhaust lines connected to the stage for discharging gas including process by-products generated during the baking process; And And control units connected to the exhaust lines, respectively, to adjust the flow rate of the gas exhausted through the exhaust lines to a predetermined reference flow rate. The baking apparatus as claimed in claim 1, wherein the stage has a plurality of holes communicating with the exhaust lines, and the holes are arranged at regular intervals along an edge of the stage. The baking apparatus of claim 1, further comprising a pump connected to the exhaust lines, wherein the pump and the exhaust lines are connected through a second exhaust line. The baking apparatus according to claim 1, further comprising a purge gas supply unit connected to the cover and configured to supply purge gas to the space. 5. The baking apparatus according to claim 4, further comprising a shower plate coupled to the cover and configured to uniformly supply the purge gas to the space.

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