JP2006049724A - Exposure mask and aligner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exposure mask and an aligner which can expose inexpensively and accurately. <P>SOLUTION: A temperature detection means for detecting the temperature of the mask 10 is provided in an exposure light irradiation region at the periphery of a fine opening pattern formed on an exposure mask 10. A control means 51, on the basis of the temperature information from the temperature detection means, controls exposure conditions (exposure quantity, exposure time) of an exposure means 7 for applying exposure light onto the mask 10, and keeps the temperature of the mask 10 at a predetermined temperature. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an exposure mask and an exposure apparatus, and more particularly to an apparatus that performs exposure using near-field light.

  In recent years, further miniaturization of photolithography has become indispensable as the capacity of semiconductor memories has increased and the speed and integration of CPU processors have increased. Here, in general, the limit of microfabrication in the photolithography technology is about the wavelength of light to be used. Therefore, in order to further miniaturize, the wavelength of light used in an optical lithography apparatus has been shortened, and at present, Fine processing of about 0.1 μm with an ultraviolet laser is possible.

  However, optical lithography is progressing in this way, but in order to carry out microfabrication of 0.1 μm or less, there is a need to solve problems such as further shortening the laser wavelength and developing an optical lens in that wavelength range. There are many issues that must be solved.

  On the other hand, an exposure apparatus using the principle of a near-field optical microscope (SNOM) using near-field light has been proposed as means for enabling fine processing of 0.1 μm or less with light. As such an exposure apparatus, for example, the exposure mask is made of an elastic body, and the exposure mask is elastically deformed so as to follow the resist surface shape of the object to be exposed. A structure is proposed in which pattern exposure is performed on an object to be exposed that exceeds the wavelength limit of light using near-field light that exudes from a minute aperture pattern having a size of 100 nm or less formed on an exposure mask. (See Patent Documents 1 and 2.)

  By the way, in such an exposure apparatus, if exposure light is continuously irradiated to the exposure mask, thermal energy is accumulated in the exposure mask. If thermal energy is accumulated in the exposure mask in this way, the heat accumulation and heat release of the exposure mask depend on the exposure sequence and illumination conditions of the photosensitive substrate that is the object to be exposed. An error occurs in the dimension of the pattern image transferred to the surface. That is, when heat accumulation occurs in the exposure mask, the exposure mask expands and a transfer error occurs.

  Therefore, in order to prevent thermal energy from being accumulated in the exposure mask in this way, conventionally, for example, an exposure mask or a temperature control clean unit that blows air over the entire exposure unit including the exposure mask is provided, and this Attach a resistance temperature detector to the air outlet of the temperature control clean unit and measure the temperature at the outlet, or detect the temperature of the exposure mask with a non-contact temperature sensor, or connect the resistance temperature detector to the exposure mask. By mounting outside the exposure effective irradiation area, measure the temperature outside the exposure effective irradiation area, feed back the measurement result, and adjust the temperature to supply the exposure mask or the entire exposure area. The temperature control of the entire part and exposure mask was performed.

Japanese Patent Laid-Open No. 11-145051 JP-A-11-184094

  However, in the conventional exposure apparatus in which the exposure mask itself is air-cooled in this way to suppress the thermal expansion of the exposure mask accompanying exposure and correct the magnification error in pattern transfer, the temperature control is actually performed. Since it is difficult to control the temperature of the exposure mask that is the target of the exposure, the expansion of the exposure mask cannot be effectively suppressed, and an active countermeasure is taken against the transfer accuracy of the minute aperture pattern of the exposure mask. I couldn't take it.

  In addition, when cooling is performed by blowing air, there is a possibility that mist generated by the blowing of air may occur in the vicinity of the exposure mask. Further, when the temperature sensor unit is attached to the exposure apparatus side, or when it is attempted to manage the temperature of the exposure mask or the entire exposure unit, installation costs and running costs increase.

  Accordingly, the present invention has been made in view of such a current situation, and an object of the present invention is to provide an exposure mask and an exposure apparatus that are inexpensive and can perform exposure with good accuracy.

  The present invention provides an exposure mask composed of an elastic body and having a minute aperture pattern, and provided with a temperature detection means for detecting the temperature of the exposure mask in an exposure light irradiation region around the minute aperture pattern. It is characterized by.

  The present invention also provides an exposure apparatus that performs exposure in a state in which an exposure mask made of an elastic body and having a minute aperture pattern is elastically deformed and in contact with an object to be exposed. An exposure means for irradiating, a temperature detection means for detecting the temperature of the exposure mask disposed at the periphery of the minute aperture pattern, and a temperature of the exposure mask based on temperature information from the temperature detection means And a control means for controlling the exposure conditions of the exposure means so as to keep the temperature at a predetermined temperature.

  As in the present invention, a temperature detecting means for detecting the temperature of the exposure mask is provided at the periphery of the minute opening pattern of the exposure mask, and the exposure conditions are controlled based on the temperature information from the temperature detecting means. By keeping the temperature of the mask at a predetermined temperature, it is possible to perform exposure with low cost and good accuracy.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a view showing the schematic arrangement of an exposure apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 50 denotes a near-field exposure apparatus. The near-field exposure apparatus 50 adjusts the pressure in the pressure adjustment chamber 2, the exposure light source 7 as an exposure means, the stage 5, and the pressure adjustment chamber 2. A pressure adjusting device 6 having a drive cylinder 6a is provided.

  Further, in FIG. 1, reference numeral 10 denotes an exposure mask attached to the bottom surface of the pressure adjusting chamber 2. This exposure mask 10 includes a mask support 12, a mask base material 11, a light shield as shown in FIG. It is composed of a film 13. Here, the light shielding film 13 is formed so as to be held on the mask base material 11, which is a thin film made of an elastic material and having a thickness of about 0.1 μm to 100 μm. A desired exposure pattern 14 which is a pattern is formed.

  Further, at least a central portion of the exposure mask 10 that is removed from the mask support 12 is an elastically deformable thin film portion 17. In the following description, the surface of the exposure mask 10 shown in FIG. 2A, that is, the surface provided with the light shielding film 13 is referred to as the front surface, and the opposite side is referred to as the back surface. The exposure mask 10 is attached to the bottom surface of the pressure adjusting chamber 2 via the mask support 12.

  In FIG. 1, W is a substrate that is an object to be exposed mounted on a stage 5 that is a moving means that can move in a two-dimensional direction in the mask plane and in a normal direction of the mask plane. A resist R is formed on the substrate. Then, the substrate W is mounted on the stage 5 and the stage 5 is driven to perform relative alignment in the two-dimensional direction in the mask surface of the substrate W with respect to the exposure mask 10, and thereafter in the normal direction of the mask surface. I try to move it.

  In FIG. 1, reference numeral 8 denotes a collimator lens for making the exposure light L emitted from the exposure light source 7 parallel light. The exposure light L converted into parallel light by the collimator lens 8 is stored in the pressure adjustment chamber 2. It is introduced into the pressure adjusting chamber 2 through a glass window 2b provided on the upper surface.

  Next, an exposure method of the near-field exposure apparatus 50 configured as described above will be described.

  First, the exposure mask 10 is arranged on the bottom surface of the pressure adjustment chamber 2 with the back side, that is, the mask support 12 faces the mask chuck 3 of the pressure adjustment chamber 2, and is then adsorbed by the exhaust means 4. Then, the deflection of the exposure mask 10 is adjusted by adjusting the pressure.

  Next, the substrate W is mounted on the stage 5 and the stage 5 is driven to perform relative alignment in the two-dimensional direction in the mask plane of the substrate W with respect to the exposure mask 10. The mask surface is moved in the normal direction until the distance reaches a predetermined set distance. The set distance is preferably close enough that the thin film portion 17 of the exposure mask 10 and the surface of the resist R do not contact each other within 100 μm.

  Next, in order to make the pressure in the pressure adjustment chamber 2 higher than that outside the pressure adjustment chamber 2, the gas is fed into the pressure adjustment chamber 2 by driving the drive cylinder 6 a of the pressure adjustment means 6. When the pressure in the pressure adjusting chamber 2 becomes higher than the outside air, the pressure is applied to the exposure mask 10 from the back surface to the front surface. As a result, as shown in FIG. The thin film portion 17, that is, the exposure pattern 14 and the peripheral region outside thereof are elastically deformed (bent) toward the substrate side, and the exposure mask 10 and the resist R on the substrate W are in close contact with each other.

  A pressure sensor 2 a is installed in the pressure adjustment chamber 2, and a control device 51 provided outside or at a predetermined position of the near-field exposure apparatus 50 monitors the pressure sensor 2 a to adjust the pressure adjustment means 6. The drive is controlled. When the control means 51 determines from the pressure information output from the pressure sensor 2a that the exposure mask surface and the resist R have reached a predetermined contact state, the control means 51 stops driving the pressure adjusting means 6.

  Next, after the exposure mask 10 is brought into close contact with the resist R in this way, the exposure light L emitted from the exposure light source 7 is collimated by the collimator lens 8, and then passed through the glass window 2b to pass through the pressure adjustment chamber 2. Then, the exposure mask 10 is irradiated from the back surface. Thereby, near-field light oozes out from the minute opening pattern 14 formed in the light shielding film 13 on the mask base material 11 of the exposure mask 10, and the resist R on the substrate W is exposed by this near-field light. .

  Next, after such an exposure process is completed, the gas in the pressure adjustment chamber 2 is exhausted to be equal to the atmospheric pressure outside the pressure adjustment container. Thereby, the bending of the exposure mask 10 is eliminated, and the exposure mask 10 is peeled from the substrate W. At this time, if there is an adsorption force between the exposure mask 10 and the substrate W, the exposure mask 10 may not be peeled from the substrate W even if the pressure inside and outside the pressure adjustment container is equalized. In this case, the exposure mask 10 is bent upward in the figure by lowering the atmospheric pressure inside the pressure adjusting container to be lower than the outside atmospheric pressure so as to increase the peeling force.

  By performing the above steps, the exposure process is completed and a desired pattern can be exposed on the substrate W. In the present embodiment, a pressure application method for applying pressure to the exposure mask 10 is used as a method for bending the exposure mask 10, but in addition, for example, between the exposure mask 10 and the substrate W. Although there is a method in which an electrostatic force is generated and the exposure mask 10 is bent toward the substrate W by the electrostatic force, the present invention is not limited to any method of bending the exposure mask 10.

  In FIG. 2, reference numeral 15 denotes a thin film resistance thermometer which is a temperature detecting means for detecting the temperature of the exposure mask 10, and the thin film resistance thermometer 15 is an exposure light irradiation (effective) region of the exposure mask 10. The center portion of the exposure pattern 14 is deposited and formed in the peripheral region between the exposure pattern portion 14A where the mask support 12 is formed. Further, electrodes 16a and 16b for inputting signals to the control device 51 (see FIG. 1) are disposed on the thin film resistance thermometer 15 disposed around the exposure pattern portion 14A.

  When the temperature information from the thin film resistance thermometer 15 is input via the electrodes 16a and 16b, the control device 51 detects the temperature, exposure time, and exposure of the exposure mask 10 previously obtained through experiments and the like. The exposure conditions are adjusted based on the reference data indicating the relationship with the exposure conditions such as the amount and the temperature information, and thereby the temperature of the exposure pattern portion 14A of the exposure mask 10 can be accurately adjusted. it can.

  Here, since the thin film resistance thermometer 15 is composed of a thin film such as platinum, and has high-speed response and a small heat capacity, the controller 51 determines the temperature of the exposure pattern portion 14A. Can be grasped at high speed and with high accuracy.

  The exposure mask 10 is manufactured by the following steps.

  First, as shown in FIG. 3A, a mask base material 11 is formed on both surfaces of a mask support base material 12a to be the mask support 12, and thereafter, as shown in FIG. 3B. Then, the mask base material 11 on one side of the mask support base material 12a is aligned and patterned so as to be an etching mask when the exposure mask 10 is manufactured.

  Next, as shown in FIG. 3 (c), a light shielding film 13 is formed on the mask base material 11 on the non-patterned side, and thereafter, as shown in FIG. 3 (d), the light shielding film is formed. 13 is processed to produce an exposure pattern 14 that is a fine pattern. At this time, the light shielding film 13 is removed at the same time as the electrodes 16a and 16b, which are the output ends of the thin film resistance thermometer 15.

  Next, as shown in FIG. 4A, a thin film resistance thermometer 15 made of, for example, a platinum thin film is formed by vacuum deposition using a metal mask, and thereafter, as shown in FIG. As shown in FIG. 3A, the mask support base material 12a on the patterned side in FIG. 3B is etched to produce the exposure mask 10. The step of etching the mask support base material 12a may be performed before the light shielding film 13 or the exposure pattern 14 is formed.

  Next, the temperature control operation of the exposure mask 10 in the near-field exposure apparatus 50 configured as described above will be described.

  First, as shown in FIG. 5A, the temperature of the exposure pattern portion 14A when the exposure mask 10 is separated from the resist R of the substrate W, that is, in the state before exposure, is measured by thin film measurement before the exposure starts. It is detected by the temperature resistor 15.

  Next, as shown in FIG. 5B, the exposure mask 10 is bent and brought into close contact with the entire surface of the resist R. When the exposure mask 10 is in close contact with the entire surface of the resist R in this way, the thin film resistance thermometer 15 is also in close contact with the resist R. Thereafter, when the exposure light is irradiated, the thin film resistance thermometer 15 A detection value proportional to the temperature is obtained by the temperature-resistivity characteristic of the film resistance thermometer 15.

  Here, when there is no temperature change of the exposure pattern 14, there is no output change between the electrodes 16a and 16b of the thin film resistance temperature detector 15. However, a plurality of shots are exposed and thermal energy is accumulated to expose the exposure pattern portion. When the temperature of 14A rises, the resistance of the thin film resistance thermometer 15 changes accordingly, and the output voltage changes according to this resistance change, and is input to the control device 51 as temperature information of the exposure pattern portion 14A.

  Next, when the temperature information is input from the thin film resistance thermometer 15 in accordance with the temperature change of the exposure pattern portion 14A in this way, the control for controlling the exposure conditions so as to keep the temperature of the exposure mask 10 at a predetermined temperature. The control device 51, which is a means, uses the temperature information and the reference data indicating the relationship between the exposure conditions obtained in advance and the temperature of the exposure mask 10, without accumulating thermal energy and at the optimum temperature. Exposure is performed by adjusting (controlling) the exposure amount and the irradiation time of the exposure light source 7 as exposure conditions so that the exposure operation can be performed.

  Then, the thin film resistance thermometer 15 is provided in the exposure light irradiation (effective) region in the peripheral portion of the exposure pattern portion 14A as described above, and the exposure condition (exposure) is based on the temperature information from the thin film resistance thermometer 15. By controlling the exposure amount and exposure time of the light source 7 for exposure, the temperature of the exposure mask 10 can be maintained at a predetermined temperature.

  As a result, it is possible to prevent the exposure mask dimension error from occurring due to the expansion and contraction of the exposure pattern 14 due to the temperature change of the exposure mask 10, thereby performing exposure with good accuracy. Furthermore, by adjusting the exposure conditions in this way so as to keep the temperature of the exposure mask 10 at a predetermined temperature, it is not necessary to control the temperature of the entire exposure apparatus, and the temperature adjustment equipment and the temperature adjustment capacity can be reduced. Is possible. As a result, it is possible to save space for the entire exposure apparatus and to reduce the cost and power consumption required for providing the exposure apparatus.

  Furthermore, as in the present embodiment, the temperature of the exposure pattern portion 14A is accurately detected by directly detecting (measuring) the temperature of the exposure pattern portion 14A during exposure using the thin film resistance thermometer 15 and controlling the exposure. And can be managed in a short time.

  In the above description, the case where the exposure amount and the exposure time of the exposure light source 7 are controlled based on the temperature information from the thin film resistance thermometer 15 has been described. However, the present invention is not limited to this, and the exposure light source is not limited thereto. 7 may be controlled at least one of the exposure amount and the exposure time.

1 is a view showing a schematic configuration of an exposure apparatus according to an embodiment of the present invention. The figure explaining the structure of the mask for exposure used for the said exposure apparatus. The 1st figure which shows the manufacturing process of the said mask for exposure. The 2nd figure which shows the manufacturing process of the said mask for exposure. The figure explaining the temperature control operation | movement of the mask for exposure in the said exposure apparatus.

Explanation of symbols

2 Pressure adjustment chamber 7 Exposure light source 10 Exposure mask 12 Mask support 13 Light shielding film 14 Exposure pattern 14A Exposure pattern portion 15 Thin film resistance temperature detector 17 Thin film portion 50 Near field exposure device 51 Control device L Exposure light R Resist W Substrate

Claims (5)

In an exposure mask composed of an elastic body and having a fine aperture pattern,
An exposure mask comprising temperature detecting means for detecting a temperature of the exposure mask in an exposure light irradiation region in a peripheral portion of the minute aperture pattern.   2. The exposure mask according to claim 1, wherein the temperature detecting means uses a thin film resistance thermometer. In an exposure apparatus that is composed of an elastic body, elastically deforms an exposure mask having a minute aperture pattern, and performs exposure in a state where the exposure mask is in contact with an object to be exposed.
Exposure means for irradiating exposure light to the exposure mask;
A temperature detecting means disposed on the periphery of the microscopic aperture pattern for detecting the temperature of the exposure mask;
Control means for controlling exposure conditions of the exposure means so as to keep the temperature of the exposure mask at a predetermined temperature based on temperature information from the temperature detection means;
An exposure apparatus comprising:   4. The exposure apparatus according to claim 3, wherein the exposure condition is at least one of an exposure amount and an exposure time of the exposure means. 5. The exposure apparatus according to claim 3, wherein the temperature detecting means is a thin film resistance thermometer and is disposed in an exposure light irradiation region in a peripheral portion of the minute aperture pattern.

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