JPS6120322A - Method for exposing material of semiconductor wafer by mercury lamp - Google Patents

Abstract

PURPOSE:To restrain the decrease in a quantity of light emission with time by repeating the first step in which electric power consumption of a mercury lamp becomes a high level under the condition that the power consumption increases gradually according to the passage of lighting time of the mercury lamp. CONSTITUTION:In the first step A in which an electric power consumption becomes a high level, a shutter 4 is open for the predetermined time under the condition that a mercury lamp 1 has been lighted. In the second step B in which the power consumption becomes a low level, the condition is shifted to one that the mercury lamp 1 is lighted, during which the shutter 4 is closed. The exposure is effected by relatively combining the first and second steps A and B, opening and closing operations of the shutter 4, and a step shift of a semiconductor material 2. Under such condition that the power consumption in the first step A increases gradually according to the passage of lighting time of the mercury lamp 1 straight, curvedly or stepwise the first step A is repeated so as to prevent a decrease in a quantity of exposing light during the respective step A.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of exposing semiconductor sea urchin material using a mercury lamp.

[Background of the invention]

When manufacturing semiconductor devices such as general 1cIc, LSI, and ultra-LSI'rL, it is safe to print a pattern on a semiconductor wafer material such as silicon through a photomask. Baking of such a pattern is carried out, for example, to form a resist layer for etching, and in this case, an ultraviolet green-sensitive resist layer pressure photomask formed on a semiconductor wafer is usually used. A widely used method is to expose the material to light using a mercury lamp.

A semiconductor wafer is usually circular in shape and its entire surface is divided into micro-areas arranged vertically and horizontally, and these micro-areas are divided under pressure to form chips that each constitute an entire semiconductor device. Large mackerel of one semiconductor wafer (generally about 3 inches, 5 inches, or 6 inches in diameter,
As semiconductor 9ever manufacturing technology advances, there is a trend toward larger sizes.

Simultaneously VcII on the entire surface of one semiconductor 9ever material! In the exposure method where Vc@ is applied once to all the microscopic areas at one time, a human-powered mercury lamp is required to expose a large 8 surface 8Wr at once, and the exposure equipment becomes large due to its slow nature.
Moreover, since one II element surface ejection is large, there are problems such as the need for considerably advanced technology to uniformize the illuminance at the exposed area where the semiconductor wafer material is exposed, resulting in larger semiconductor wafers. Trend VC: 1Ili is difficult to respond to.

[Prior art]

For this reason, recently, an exposure method (hereinafter referred to as "kFI") in which one piece of conductor material [jcI, each of the microscopic areas arranged vertically and horizontally is sequentially exposed and printed as a pattern kFI11 (hereinafter referred to as A single IC (also referred to as the "step wL element method") was proposed. According to the step exposure method as shown in C, it is only necessary to expose the area of one minute area at a time, and for this reason, it is necessary to use a small output mercury lamp.
This makes it possible to reduce the size of the exposure equipment, and because the area exposed at one time is small, it is easy to equalize the illumination intensity at the exposed area of the semiconductor 9 ever, which brings many benefits to many people. 5. As a result, it is possible to print a turn with high accuracy.

When the mercury lamp is turned off, the mercury gas sealed in K condenses, so it is not possible to repeat blinking in a short period of time. In order to carry out the exposure with a predetermined amount of exposure, a shutter is used to limit the exposure time, and while this shutter is closed, the next exposure of the semiconductor wafer material is carried out at the exposure position where the source from the mercury lamp is irradiated. Where should the conductor material be located so that the micro-areas should be located? It is necessary to move in steps (hereinafter also simply referred to as "step movement").

However simply due to traditional exposure methods like this? However, when the shutter is closed, the mercury lamp is not used for exposure, which wastes a lot of power, and the shutter is exposed to high-temperature VC, which causes serious damage to the white of the eye shutter.

For this reason, it is conceivable to consider a method in which the mercury lamp is fully turned on in such a manner that the power consumption of the mercury lamp during the period when the shutter is closed is smaller than the power consumption during the exposure period when the shunter is open.

However, like this! It has been discovered that the llll method has new problems. (Immediately) With the speeding up of the exposure process for cow conductor wafer materials, continuous points 1. When the mercury lamp is turned on, the amount of light emitted by the mercury lamp decreases due to factors such as wear on the tt@ and a decrease in the original transmittance due to the adhesion of the electrode@ material to the tube wall, and the amount of light emitted from the mercury lamp decreases as the lighting time of the mercury lamp increases. This is a problem that makes it impossible to perform exposure with a certain amount of light.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and its purpose is to suppress the decrease in the amount of emitted light from a mercury lamp over time at a low cost, and to prevent exposure that is repeatedly performed at short time intervals for a long period of time. It is an object of the present invention to provide a method for exposing a semiconductor wafer material using a mercury lamp, which can be stably performed over a period of time.

[Structure of the invention]

The above purpose is to alternately repeat the first step in which the power consumption of the mercury lamp is at a high level and the second step in which the power consumption of the mercury lamp is at a low level while the mercury lamp is lit continuously at Vc, and In step 1, an exposure method is used in which the semiconductor material is exposed to light emitted from the mercury lamp.

This is achieved by a method of exposing a conductive wafer material using a mercury lamp, which is characterized in that the first step t is repeated with the power consumption gradually increasing 1 as the illumination time of the mercury lamp passes.

The present invention will be described in detail below with reference to the drawings.

In one embodiment of the invention, for example, as shown in FIG.
After constantly supplying power to the mercury lamp lt to keep it in a continuous lighting state, the power supplied to the mercury lamp 1 is fully controlled as shown in Figure 2, an example of the power consumption waveform. The first step A is when the power consumption is high, for example, about 13 to 2.5 times the rated power consumption.
Then, the power consumption of the mercury lamp 1 is at a low level, for example, the rated power consumption or a level close to this, and the second step B and t are periodically alternately repeated, and the source radiated from the mercury lamp 1 in step AK3 of the tail 1 is L-shaped semiconductor wafer material 2'
It costs 1 yuan. In Figure 1, 3 is a power supply circuit for driving the mercury lamp l, 4 is a shutter for driving the mercury lamp l, 5, 6.7 are reflectors, 8 is an integrator, 9 is a filter, and 1 Otl condenser lens. , II
It is an H photomask and a 12 tl reduction lens, and the ia degree is usually 10''=5.

In regulating the exposure amount, the opening time of the shutter 4 should be set appropriately.℃, semiconductor wafer material 2
The amount of exposure applied to the exposed part of the body is adjusted to a safe prescribed value. That is, the first step AK where the power consumption is at a high level
It is assumed that the amount of exposure is regulated by keeping the shutter 41i-B open for the time period in which the mercury lamp 1 is lit. Then, in the second step B&C, in which the power consumption is at a low level, the mercury lamp is turned on, and during this time the shutter remains on.
is closed.

The repetition of the first step A and the second step B is
Relationship with the mode of step movement of semiconductor 9 ever material 2 V
cX and interlock with each other.

P) As shown in FIG. 3, the exposed area of the semiconductor 9 material 2 is divided into a large number of micro-areas P arranged vertically and horizontally, and one of these micro-areas P is sequentially placed at the exposure position in a stepwise manner. Is it possible to move the camera to a position and then expose it while it is still at that position? Let's do it. One exposure is completed by opening and closing the shutter 4, and a turn is printed on one minute area P of the semiconductor material 9. Then, while the shutter 4 is closed, the minute area to be exposed next is moved step by step to the original position of phgK, and in the same manner M is repeated nine times.

With this pressure, the first step A and the second step B
, the opening/closing operation of the shutter 4, and the semiconductor wafer material 2
Exposure is performed in conjunction with the step movement of the mercury lamp 1, but as the lighting time of the mercury lamp 1 elapses, the power consumption of the 1st Q step AVcg gradually increases as shown in FIG. The first step At- is repeated so that a decrease in the exposure amount in each step A of il is prevented with a gradual or stepwise increase. The degree of increase in power consumption may be determined empirically based on the baking results of the semiconductor material, or the radiation source of the mercury lamp may be directly detected using a source sensor and based on this detected value. Alternatively, the piezoelectric power circuit section 3iC may control the amount of emitted light to be constant.

FIG. 5 shows an example of a specific configuration of a mercury lamp l, 101
is a quartz glass enclosure, 102A and 102B are caps, 1
03 and 104 are electrode rods, respectively, and 105 and 106 are an anode body and a cathode body, respectively. The inside of the envelope 101 is filled with mercury, and the amount of mercury sealed is such that the mercury does not condense when the mercury lamp 1 is turned on in step B of WJ2.

The anode body 105 is shown enlarged in FIG.
A large diameter cylindrical body portion 51, a tip portion 53 extending from the body portion 51 in a tapered shape and having a flat tip surface 52, and Vc.
The cathode body 106, as shown in FIG. Ru.

An example of a specific design of such a mercury lamp is shown below. Rated Mtt power 500W (50V, 10A)
Outer diameter D of anode body shape body 51 14.0 m Diameter of tip surface 52 D 22.0 Opening angle α of tip 53 90 degrees Outer diameter D5 of cathode body shape columnar part 61 2. Olol Distance between electrodes L 3.0 Pressure inside the envelope when lit at rated power consumption 13 atm Mercury lamp with such a configuration? When we actually carried out binding of semiconductor wafer materials under the following conditions using the method described above, the initial exposure amount was stably obtained at 1 for a long period of about 600 hours, and the semiconductor wafer material We were able to perform an excellent exposure process on the material.

First step A time interval 400m5ec2nd
The initial power consumption in step AK of step B of 400 m5ec compilation was 750 W, and the power consumption was increased to approximately 111 w so that it would reach IKW after 600 hours.

In the second step, 600 hours have passed since the initial power consumption in BICg, and the power consumption was maintained constant at 500WK.

[Function and effect of the invention]

More details Vci! As explained above, the method of the present invention provides the following effects.

The power consumption of the mercury lamp is at a low level during the period when the synchrotron radiation of the mercury lamp is not used for exposure.Since the mercury lamp is turned on in the second step, the power wasted by the mercury lamp can be significantly reduced, and the shutter It can completely prevent overheating damage, and the mercury lamp is
In addition, in the first step, the power consumption of the mercury lamp is at a high level, so in the second step, the necessary exposure amount can be used. exposure of semiconductor wafer materials can therefore be carried out with a smaller mercury lamp,
As a result, the volume occupied by the exposure apparatus becomes smaller, the cost required for maintenance of a clean room, etc. is reduced, and as a result, it becomes possible to significantly reduce the manufacturing cost of semiconductor devices.

(Then, the entire first step is repeated while the power consumption is gradually increased as the lighting time of the mercury lamp passes.) This first step is followed by exposure of the semiconductor wafer material.
Therefore, even if a mercury lamp suffers from wear of the electrodes or a decrease in light transmittance due to electrode material adhering to the tube wall, the lack of light intensity will be compensated for by the increased power consumption VC, so the first step will still be effective. It is possible to maintain the amount of radiation of the mercury lamp at 1'8j as the initial value, and by repeating the first step and the second step at short time intervals, the amount of radiation of the mercury lamp can be maintained stable for a long period of time. Deposition of semiconductor wafer material at 5'1 can be carried out at 0

[Brief explanation of the drawing]

@1 Figure is an explanatory diagram schematically showing an example of an exposure device,
Fig. 2 is an explanatory diagram showing an example of the waveform of the power consumption of a mercury lamp that changes depending on the repetition button of the first step and the second step, and Fig. 3 is an explanatory diagram showing a part of the exposed portion of the semiconductor wafer material. , Figure 4 shows a state in which the power consumption in the first step gradually increases as the lighting time of the mercury lamp passes.
Figure 5 is an explanatory diagram showing an example of a mercury lamp, Figure 6 is an explanatory diagram showing an example of a mercury lamp.
The figure is an explanatory diagram showing an enlarged view of the main parts of the mercury lamp shown in FIG. 5. l...Mercury lamp 2...Semiconductor wafer material 3...Drive power supply circuit section 4...Shutter 5.6.7...Reflector 8...Integrator 9...Filter lO ... Condenser lens 11 ... Photomask 12 ... Reduction lens 101 ... Envelope 102A, 102B 9
1 base 103.104...electrode rod 105...I
II pole body 51...Body part 52...Tip face 53...Tip part 106...Cathode body 61.
...Columnar part 62... Tip part 9p1 figure y2 decoy sheep 3 decoy 4th figure B'faI (hour)

Claims (1)

[Claims] 1) Alternately repeating a first step in which the power consumption of the mercury lamp is at a high level and a second step in which the power consumption of the mercury lamp is at a low level while the mercury lamp is continuously lit;
An exposure method in which a semiconductor wafer material is exposed to light emitted from the mercury lamp in the first step, wherein the first step is performed in a state in which power consumption gradually increases as the lighting time of the mercury lamp passes. A method for exposing a semiconductor wafer material using a mercury lamp, characterized by repeatedly exposing a semiconductor wafer material to