JP2004319833A - Baking apparatus, and heat treatment method of substrate used therefor and manufacturing method of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a baking apparatus capable of detecting an unbalanced rise of a substrate on a heating plate and defective heat treatment caused thereby with high accuracy at a low cost. <P>SOLUTION: The baking apparatus related to one embodiment is provided with: the heating plate for applying heat treatment to the substrate placed thereon; a stand placed movably in vertical directions having at least three support pins penetrated through through-holes opened to the heating plate to support the substrate on the heating plate from its rear side; and a plurality of sensors respectively located at the tip of each support pin so as to sense contact between each pin and the substrate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a baking apparatus used for heat treatment of a substrate in a process of manufacturing various substrates such as a semiconductor substrate for a semiconductor device, a glass substrate for a photomask, and a glass substrate for a liquid crystal display device, and a heat treatment method for a substrate using the same. And a method for manufacturing a semiconductor device.
[0002]
[Prior art]
A baking apparatus that performs heat treatment on a semiconductor substrate in a manufacturing process of a semiconductor device is often used particularly in a lithography process.
[0003]
Specific applications of the baking apparatus include, for example, a drying process after forming a photoresist film on a semiconductor substrate by a spin coating method, and a photo-decomposed photosensitive agent in the resist film after transferring a pattern to the photoresist film. (Post Exposure Bake: post-exposure bake) processing to diffuse the GaN and make the concentration distribution uniform. More recently, the semiconductor substrate is heated by heating after developing, forming a pattern, and forming a pattern. A baking apparatus is also used in a flow baking process for arbitrarily changing a pattern dimension by thermally deforming.
[0004]
In addition to the lithography process, a quenching process for rapidly cooling the semiconductor substrate temperature from a temperature equal to or higher than the melting point of copper to about room temperature in order to make the distribution of copper in the aluminum-copper (Al-Cu) film uniform. Baking equipment is also used.
[0005]
In any of the processes, temperature uniformity over the entire semiconductor substrate is very important together with accuracy of the temperature applied to the semiconductor substrate.
[0006]
Regarding the temperature accuracy of the baking apparatus, for example, a temperature accuracy of about ± 0.2 ° C. has already been realized in a hot plate provided in a baking apparatus for processing a semiconductor substrate having a diameter of 8 inches.
[0007]
However, regarding the uniformity of the processing temperature in the baking apparatus, a sufficiently accurate apparatus including means for confirming whether or not the semiconductor substrate has been processed at a uniform processing temperature over the whole is not necessarily realized. This problem will be described, including measures for accurately placing the semiconductor substrate on the center of the hot plate.
[0008]
FIG. 8 is a plan view (FIG. 8 (a)) and a side view (FIG. 8 (b)) showing a state where the semiconductor substrate is placed at the center on the hot plate of the baking apparatus. FIG. 9A is a plan view (FIG. 9A) and FIG. 9B is a side view (FIG. 9B) showing a state in which the substrate is placed on a hot plate of the baking apparatus so as to be shifted from a central portion thereof.
[0009]
As shown in FIGS. 8A and 8B, when the semiconductor substrate is placed at the center without protruding from the hot plate and subjected to heat treatment, uniformity of the processing temperature is ensured, and There is no problem with the quality of the product.
[0010]
However, as shown in FIGS. 9A and 9B, the semiconductor substrate may be placed with a part thereof protruding from the hot plate.
[0011]
Such a displacement is due to a coordinate displacement of a robot arm for transferring a semiconductor substrate onto a hot plate, and is caused by insufficient adjustment of the robot arm, deterioration over time, or sudden noise.
[0012]
When the degree of displacement is large, when the robot arm takes out the semiconductor substrate from the baking device, the arm and the semiconductor substrate collide at an unscheduled place, and one or both of the arm and the semiconductor substrate may be damaged. .
[0013]
Therefore, the baking apparatus is usually provided with a mechanism for preventing the semiconductor substrate from being displaced.
[0014]
FIG. 10 is a plan view (FIG. 10 (a)) and a side view (FIG. 10 (b)) of a hot plate of a baking apparatus provided with a mechanism for preventing displacement of a semiconductor substrate.
[0015]
In the baking apparatus shown in FIG. 10, four guide members 2 for preventing the semiconductor substrate 6 from being displaced are provided on the peripheral portion of the hot plate 1. Such a guide member 2 is generally used as a mechanism for preventing displacement of a semiconductor substrate. For example, like a guide member 2 shown in FIG. By providing a guide member processed into an inclined surface having a lower central part side on a part or all of the peripheral part of the hot plate 1, even if the end of the semiconductor substrate 6 rides on the guide member 2 due to displacement. The misalignment of the semiconductor substrate 6 is corrected by sliding down to the center of the hot plate 1, thereby preventing a transport trouble due to the misalignment of the semiconductor substrate.
[0016]
However, even if the guide member 2 as described above is provided on the peripheral edge of the hot plate 1, the end of the semiconductor substrate 6 that has ridden on the guide member 2 due to positional displacement slides completely toward the center of the hot plate 1. A phenomenon of one-sided movement that stops halfway without falling may occur.
[0017]
FIG. 11 is a side view of the semiconductor substrate and the hot plate showing a one-sided state in which the semiconductor substrate rides on the guide member and stops.
[0018]
As shown in FIG. 11, when the semiconductor substrate 6 is subjected to a heat treatment while the semiconductor substrate 6 is in an upside-down state, especially between the semiconductor substrate 6 and the hot plate 1 at a portion surrounded by a dotted line shown in FIG. Non-uniform air gaps are generated, resulting in a difference in the amount of heat directly or indirectly applied from the hot plate 1 depending on the location of the semiconductor substrate 6, and a uniform heat treatment over the entire semiconductor substrate is not performed.
[0019]
When a non-uniform heat treatment is performed on a semiconductor substrate, a non-uniform resist film thickness occurs in a drying process after application of the resist, and a dimensional defect occurs in a PEB process or a flow bake process.
[0020]
Usually, in the lithography process, the pattern size of the semiconductor substrate after pattern formation is measured using a scanning electron microscope (SEM) or the like, and if it is outside the allowable range, rework is performed.
[0021]
However, the dimensional variation or dimensional defect due to the displacement of the semiconductor substrate occurs in which part of the semiconductor substrate, and in which semiconductor substrate, it is a completely irregular phenomenon. It is extremely difficult to reliably detect a dimensional defect of a semiconductor substrate without overlooking it even if dimensional measurement sampling is performed at several locations.
[0022]
Therefore, conventionally, as a means for detecting the upward movement of the semiconductor substrate on the hot plate, a detection mechanism utilizing the temperature characteristics of the hot plate has been provided in the baking apparatus.
[0023]
The detection mechanism uses the temperature characteristics of the hot plate when the semiconductor substrate is normally placed on the hot plate and comes into contact with it, as a comparison model, and when the semiconductor substrate to be detected is placed on the hot plate. By measuring the temperature characteristics of the hot plate and comparing the measured temperature characteristics with the comparison model, it is determined whether or not the difference in the temperature characteristics is within a range of an allowable value, and the upward movement of the semiconductor substrate is detected.
[0024]
FIG. 12 is a graph showing temperature characteristics of the hot plate measured by the semiconductor substrate tilt detection mechanism. Curve 1 among the curves shown in the graph of FIG. 12 is a temperature characteristic of the hot plate when the semiconductor substrate is normally placed on the hot plate set at a temperature of 160 ° C. and comes into contact with the semiconductor substrate, and curve 2 is And temperature characteristics of the hot plate when the semiconductor substrate is placed on the hot plate set at a temperature of 160 ° C. in a one-sided state.
[0025]
When a relatively low-temperature semiconductor substrate is placed on a hot plate heated to a high temperature, the temperature of the hot plate temporarily drops due to a temperature difference between the two. Here, assuming that the temperature drop when the semiconductor substrate is normally placed and contacts the hot plate on the entire surface is ΔT, when the semiconductor substrate is placed in a one-sided state and only a part contacts the hot plate. The temperature drop is ΔT ′ (<ΔT), and as shown in FIG. 12, the temperature drop ΔT ′ of the hot plate when the semiconductor substrate is placed in a one-sided state and the temperature drop when the semiconductor substrate is normal It can be seen that it is smaller than ΔT.
[0026]
Therefore, in this detection mechanism, an allowable threshold value is set in advance for the temperature decrease amount ΔT, and the temperature characteristic of the hot plate when the semiconductor substrate is actually mounted on the hot plate is measured. Is larger than the permissible threshold, it is determined that the semiconductor substrate has been properly placed on the hot plate and normal processing has been performed. It is determined that the processing has been performed at an uneven processing temperature without being placed properly.
[0027]
As described above, a method and an apparatus for judging whether or not a substrate is normally placed on a hot plate by using the temperature characteristics of the hot plate when the substrate is placed on the hot plate have been described. (For example, see Patent Literature 1 and Patent Literature 2).
[0028]
In addition, a method and apparatus for providing a thermocouple inside the support pins for supporting the substrate when transferring the substrate onto or from the hot plate and directly detecting the temperature of the substrate have also been proposed. (For example, see Patent Document 3).
[0029]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-050557 [Patent Document 2]
Japanese Patent Application Laid-Open No. 2000-306825 [Patent Document 3]
JP 11-272342 A
[Problems to be solved by the invention]
However, the setting of the permissible threshold value of the temperature decrease amount ΔT requires very strict fine adjustment. If the permissible threshold value is too small, the defective process is overlooked even though the semiconductor substrate is tilted. On the other hand, if the permissible threshold is too large, it will be detected as a defective process in spite of the normal process, and at present, sufficient accuracy is not always obtained in actual defect detection.
[0031]
In addition, the temperature characteristics of the hot plate when the semiconductor substrate is normally placed on the hot plate and brought into contact therewith, that is, the amount of temperature decrease ΔT differs depending on the temperature setting of the hot plate.
[0032]
FIG. 13 is a graph showing, for each set temperature of the hot plate, a temperature decrease ΔT of the hot plate when the semiconductor substrate is normally placed on the hot plate and brought into contact with the semiconductor substrate.
[0033]
As shown in the graph of FIG. 13, the temporary temperature decrease ΔT of the hot plate when the semiconductor substrate is normally placed on the hot plate and brought into contact with the semiconductor substrate increases as the set temperature of the hot plate increases. You can see that.
[0034]
However, using one hot plate with a plurality of temperature settings and changing the setting of the allowable threshold value of the temperature decrease amount ΔT while using it requires extremely complicated and difficult work. A plurality of baking devices must be prepared for each temperature, which causes an increase in equipment cost.
[0035]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a baking apparatus capable of detecting, at a low cost and with high accuracy, a rise of a substrate on a hot plate and a heat treatment defect resulting therefrom. That is.
[0036]
[Means for Solving the Problems]
According to the baking device according to one embodiment of the present invention,
A hot plate for performing heat treatment on the mounted substrate,
A pedestal that penetrates through holes formed in the hot plate, has at least three support pins for supporting the substrate on the hot plate from the back surface, and is installed to be vertically movable;
A plurality of sensors disposed at the tip of each of the support pins, respectively, for detecting contact with the substrate,
It is characterized by having.
[0037]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a baking apparatus according to an embodiment of the present invention will be described with reference to the drawings.
[0038]
FIG. 1 is a plan view (FIG. 1 (a)) and a side view (FIG. 1 (b)) showing a hot plate and its peripheral portion of a baking apparatus according to one embodiment of the present invention.
[0039]
A baking apparatus according to one embodiment of the present invention includes a hot plate 1 for performing a heat treatment on a mounted semiconductor substrate, and a semiconductor substrate on the hot plate 1 that passes through a through hole formed in the hot plate 1. Has at least three support pins 3 for supporting the heat plate 1 from the back surface, and a pedestal 4 installed vertically movably, and an inclined surface where the center side of the hot plate 1 becomes lower, and the upper surface is machined. The semiconductor device includes a guide member 2 provided partially or entirely, and a plurality of sensors 5A, 5B, and 5C provided at the distal ends of the support pins 3 and detecting contact with the semiconductor substrate.
[0040]
The diameter of the hot plate 1 is, for example, 210 mm. Here, the specific shape of the guide member 2 is a prismatic member in which the upper surface is machined on an inclined surface in which the center portion side of the hot plate 1 is lowered, and the guide member 2 is provided at four positions on the peripheral portion of the hot plate 1. It is arranged. In addition, for example, the guide member 2 is formed by processing the upper surface of a columnar member having a diameter of 2 mm and a height of 3 mm into an inclined surface in which the central portion of the hot plate 1 becomes lower, and a peripheral portion of, for example, 102 mm from the center of the hot plate 1. The guide member 2 may be disposed at four positions, and the specific shape of the guide member 2 and the position at which the guide member 2 is disposed at the peripheral portion of the hot plate 1 are arbitrary.
[0041]
The at least three support pins 3 need only be disposed on the pedestal 4 so that a single horizontal plane is formed by their ends and the semiconductor substrate can be supported from the back surface. Are arranged in a regular triangular shape having a side of 150 mm. The number of support pins 3 may be four or more.
[0042]
The pedestal 4 is provided with a mechanism for moving the pedestal 4 up and down. By moving the pedestal 4 up and down, the semiconductor substrate supported from the back surface by the support pins 3 can be moved up and down on the hot plate 1. . The mechanism for moving the semiconductor substrate up and down operates when the semiconductor substrate is transferred between the robot arm and the baking device.
[0043]
In the baking apparatus according to one embodiment of the present invention, sensors 5A, 5B, and 5C for detecting contact with the semiconductor substrate 6 are provided at the tips of the support pins 3, respectively. Each of the sensors 5A, 5B, and 5C independently detects contact with the semiconductor substrate 6. The sensor 5 only needs to have a function of detecting contact with the semiconductor substrate. Here, for example, a piezoelectric element using ZPT (lead zirconate titanate) is used. In addition, a capacitance element or the like can be used as the sensor 5.
[0044]
Based on the configuration of the baking apparatus according to the embodiment of the present invention described above, its operation and functions will be described.
[0045]
2 to 6 are side views showing a series of operations of the baking apparatus according to one embodiment of the present invention. FIG. 7 is a side view showing a state in which the semiconductor substrate has been lifted in the baking apparatus according to the embodiment of the present invention.
[0046]
First, as shown in FIG. 2, a semiconductor substrate 6 to be subjected to a heat treatment is carried by a robot arm 7 into a space on a hot plate 1 in a baking apparatus. At this time, the pedestal 4 is adjusted so that the tip of the support pin 3 protrudes from the upper surface of the hot plate 1 and the support pin 3 does not contact the semiconductor substrate 6 on the robot arm 7.
[0047]
Next, as shown in FIG. 3, the robot arm 7 moves downward so that the semiconductor substrate 6 is supported by the support pins 3. After the semiconductor substrate 6 is transferred onto the support pins 3, the robot arm 7 moves out of the baking apparatus as shown in FIG.
[0048]
After the robot arm 7 moves out of the baking apparatus, the pedestal 4 is moved downward as shown in FIG. 5 so that the semiconductor substrate 6 is placed on the hot plate 1 and heat treatment is performed. Is placed at a height lower than the upper surface of the hot plate 1, the semiconductor substrate 6 is placed on the hot plate 1, and heat treatment is performed on the semiconductor substrate 6.
[0049]
After the heat treatment, as shown in FIG. 6, the pedestal 4 is moved upward so that the tips of the support pins 3 protrude from the upper surface of the hot plate 1, and the semiconductor substrate 6 is supported by the support pins 3 and Lift from the top. At this time, if the sensors 5A, 5B, and 5C disposed at the tips of the three support pins detect the contact with the semiconductor substrate 6 at the same timing, the semiconductor substrate 6 is normally placed on the hot plate 1, In other words, it is placed horizontally, and it can be determined that the heat treatment has been performed normally at a uniform temperature over the entire semiconductor substrate 6.
[0050]
On the other hand, as shown in FIG. 7, when the edge of the semiconductor substrate 6 rides on the guide member 2 and the one-sided movement occurs, the sensors 5A, 5B, and 5C contact the semiconductor substrate 6 at different timings. Is detected. For example, as shown in FIG. 7, the semiconductor substrate 6 rises up, and the angle between the semiconductor substrate 6 and the hot plate 1 becomes 1 ° due to the rise, and the pedestal 4 rises at a speed of 5 mm / sec. If there is, the sensor 5C first contacts the semiconductor substrate 6, the sensor 5B contacts the semiconductor substrate 6 0.26 seconds later, and the sensor 5A contacts the semiconductor substrate 6 0.26 seconds later.
[0051]
Therefore, by monitoring the contact timing of each of the sensors 5A, 5B, 5C with the semiconductor substrate 6, the semiconductor substrate 6 is normally placed on the hot plate 1, or the semiconductor substrate 6 is raised. Can be detected.
[0052]
Specifically, an arbitrary allowable value is set in advance for the time difference between the contact timings of the sensors 5A, 5B, and 5C with the semiconductor substrate 6, and when the actually measured time difference is smaller than the allowable value, the normal processing is performed. If the measured time difference exceeds the allowable value, it may be determined that the processing is defective. When a defective process is detected, a visual or audible alarm may be issued by the alarm device. Further, the operation of the baking device may be interrupted. Alternatively, when a defective process is detected, the semiconductor substrate to be processed may be automatically excluded from the manufacturing process.
[0053]
In addition, if the pedestal 4 is configured so that the ascending speed and the descending speed, at least the ascending speed, can be adjusted, the detection sensitivity can be adjusted by adjusting the ascending speed of the pedestal 4.
[0054]
Also, as shown in FIG. 3, when the semiconductor substrate 6 is transferred from the robot arm 7 onto the support pins 3, the timing of contact between the sensors 5A, 5B, and 5C with the semiconductor substrate 6 is similarly monitored. Thereby, the time difference of the contact timing caused by the distortion of the semiconductor substrate 6 itself, the inclination of the pedestal 4, and the variation of the height of the support pin 3 is measured, and the time difference of the contact timing is used to detect the contact timing after the heat treatment. If used as a correction value at this time, the occurrence of one-sided up of the semiconductor substrate 6 can be detected with higher accuracy.
[0055]
The baking apparatus according to one embodiment of the present invention has been described as being used for heat treatment of a substrate in a process of manufacturing a semiconductor substrate for a semiconductor device, but the baking apparatus according to one embodiment of the present invention has been described. In addition, the apparatus can be used for heat treatment of a substrate in a process of manufacturing various substrates such as a glass substrate for a photomask and a glass substrate for a liquid crystal display device.
[0056]
Further, in the baking apparatus according to the embodiment of the present invention, the guide member 2 has been described as being provided on a part or all of the peripheral portion of the hot plate 1, but the guide member 2 is provided. However, the configuration of the present invention can be applied even when it is not performed.
[0057]
Further, as is clear from the above description, the present invention also relates to a substrate heat treatment method including performing a heat treatment on a substrate using the baking apparatus according to one embodiment of the present invention, and a semiconductor substrate manufacturing method. It is about.
[0058]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the baking apparatus which concerns on one Embodiment of this invention, the rise of the board | substrate on a hot plate and the heat processing defect resulting from it can be detected at low cost with high precision, and generation | occurrence | production of a defective product is minimized. It can be suppressed.
[Brief description of the drawings]
FIG. 1 is a plan view (FIG. 1 (a)) and a side view (FIG. 1 (b)) showing a hot plate and its peripheral portion of a baking apparatus according to one embodiment of the present invention.
FIG. 2 is a side view showing one process in a series of operations of the baking apparatus according to one embodiment of the present invention.
FIG. 3 is a side view showing one process in a series of operations of the baking apparatus according to the embodiment of the present invention.
FIG. 4 is a side view showing one process in a series of operations of the baking apparatus according to one embodiment of the present invention.
FIG. 5 is a side view showing one process in a series of operations of the baking apparatus according to one embodiment of the present invention.
FIG. 6 is a side view showing one process in a series of operations of the baking apparatus according to one embodiment of the present invention.
FIG. 7 is a side view showing a state in which the semiconductor substrate is lifted in the baking apparatus according to one embodiment of the present invention.
8A and 8B are a plan view (FIG. 8A) and a side view (FIG. 8B) showing a state in which the semiconductor substrate is placed at the center on the hot plate of the baking apparatus.
9 is a plan view (FIG. 9 (a)) and a side view (FIG. 9 (b)) showing a state in which the semiconductor substrate is placed on a hot plate of the baking apparatus so as to be shifted from a central portion thereof.
FIGS. 10A and 10B are a plan view (FIG. 10A) and a side view (FIG. 10B) of a hot plate of a baking apparatus provided with a mechanism for preventing displacement of a semiconductor substrate.
FIG. 11 is a side view of the semiconductor substrate and the hot plate showing a one-sided state in which the semiconductor substrate is stopped while riding on the guide member.
FIG. 12 is a graph showing temperature characteristics of a hot plate measured by a semiconductor substrate tilting detection mechanism.
FIG. 13 is a graph showing, for each set temperature of the hot plate, a temperature decrease amount ΔT of the hot plate when the semiconductor substrate is normally placed on the hot plate and brought into contact with the semiconductor substrate.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hot plate 2 Guide member 3 Support pin 4 Pedestal 5A, 5B, 5C Sensor 6 Semiconductor substrate 7 Robot arm

Claims (13)

A hot plate for performing heat treatment on the mounted substrate,
A pedestal, which passes through a through-hole opened in the hot plate, has at least three support pins for supporting a substrate on the hot plate from the back surface, and is movably installed;
A plurality of sensors arranged at the tip of each of the support pins and detecting contact with the substrate,
A baking device comprising: The baking device according to claim 1, wherein the plurality of sensors independently detect contact with a substrate. The baking device according to claim 1, wherein each of the sensors is a piezoelectric element. The said each sensor is a capacitance element, The baking apparatus of Claim 1 or 2 characterized by the above-mentioned. When the time difference between the contact timings of the sensors and the substrate when the substrate is supported by the support pins after the heat treatment is arbitrarily set in advance and the measured time difference exceeds the time difference, it is determined that the defective process is detected. The baking apparatus according to any one of claims 1 to 4, wherein: The baking device according to claim 5, further comprising an alarm device that issues a visual or audible alarm when a defective process is detected. 7. The baking apparatus according to claim 5, wherein the operation is interrupted when a defective process is detected. The baking apparatus according to claim 5, wherein when a defective process is detected, a substrate to be processed is excluded from a manufacturing process. Before the heat treatment, a time difference between the contact timings of the sensors and the substrate when the substrate is transferred onto the support pins is measured, and the time difference is used as a correction value for the time difference measured after the heat treatment. The baking device according to any one of claims 5 to 8, wherein The baking apparatus according to any one of claims 1 to 9, wherein the pedestal has an adjustable rising speed. 11. The heating plate according to claim 1, wherein an upper surface is machined on an inclined surface in which a center portion side of the heating plate is lowered, and a guide member is further provided on a part or all of a peripheral portion of the heating plate. The baking device according to any one of the above. A heat treatment method for a substrate, comprising: performing a heat treatment on a substrate using the baking apparatus according to claim 1. A method for manufacturing a semiconductor device, comprising: performing a heat treatment on a semiconductor substrate using the baking apparatus according to claim 1.

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