JPS6120323A - Exposure method of semiconductor wafer material using mercury lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of exposing a copper conductor material using a mercury lamp.

[Background of the invention]

Generally IC, LS1. In the manufacture of semiconductor devices such as VLSIs, it is necessary to completely bake a pattern onto a conductive wafer material made of silicon or the like through a photomask. Baking of such a pattern is necessarily carried out by light, for example, to form a resist layer for etching, and in this case, it is usually done using an ultraviolet green-sensitive and photosensitive material formed on the conductor wire. A widely used method is to expose the resist layer to light from a mercury lamp through a photomask.

The conductor wafer is usually circular and its entire surface is divided into micro-areas arranged vertically and horizontally, and these micro-areas are later divided into chips, each forming a conductor device. The size of a single semiconductor conductor is generally about 3 inches, 5 inches, or 6 inches in diameter, but as the manufacturing technology of the conductor 9-inch progresses, it tends to become larger. I'm in the middle of the day.

In the nine method of exposing the entire surface of one conductor wafer material at the same time and applying Vcm to all the minute areas at once, it is 5.
In order to cover a large area at once, a high-output mercury lamp is required, which means that the exposure equipment must be large.
Since the exposed area is large at the same time, problems such as the need for highly sophisticated technology to uniformize the illuminance across the exposed portion of the conductor wafer material have arisen, leading to a trend toward larger H-channel semiconductor wafers. Difficult to adapt.

[Prior art]

For this reason, an exposure method (hereinafter simply referred to as "step exposure method") in which a single semiconductor wafer material is exposed one by one in each of micro areas arranged vertically and horizontally to sequentially print a pattern has been developed. ) was proposed.

According to such a step exposure method, one exposure requires g
In this case, it is only necessary to expose the surface of one minute area 8I, which makes it possible to use a small output mercury lamp sound.
The main advantages are that the original equipment can be made smaller, and since the area exposed per time is small, it is easier to equalize the illuminance of the exposed area of the semiconductor wafer. Baking can be performed.

When the mercury lamp is turned off, the mercury gas contained in it condenses, so it is not possible to repeat blinking in a short cycle, so it is used in a state where it is kept on continuously. A shutter is used to limit the total exposure time in order to use a predetermined amount of light exposure, and while this shutter is closed, the next exposure of the semiconductor wafer material VC8 is carried out at the exposure position where the source from the mercury lamp is irradiated. It is necessary to move the semiconductor wafer material in full steps (hereinafter also simply referred to as "step movement") so that the desired minute area is located.

However, with this conventional exposure method KS, the amount of exposure from the mercury lamp is not utilized while the shutter is closed, which wastes a lot of power (in addition, since the shutter is exposed to high temperatures, the shunter is not used). The problem is that the damage is large.

For this reason, a method can be considered in which the mercury lamp is turned on in such a way that the power consumption of the mercury lamp during the period when the shutter is closed is lower than the power consumption during the exposure period when the shutter is open.

However, there are new problems with this g-element method. It turned out that it has. That is, as the speed of JT processing of semiconductor wafer materials increases.

Mercury lamp? If you repeatedly turn on the light many times in a row so that the power consumption changes at short time intervals.

As the mercury lamp lighting time elapses,! The wear of the poles becomes extremely thick, which reduces the amount of light emitted by the mercury lamp, and as a result, there is a problem in that it is not possible to maintain a stable g source for a long period of time at the initial exposure amount.

[Purpose of the invention]

The present invention has been made based on the above-mentioned vO@ circumstances.The seventh object is to completely prevent wear of the electrodes of a mercury lamp at a low cost, and to provide a method over the entire period of exposure that is repeated at short time intervals. The object of the present invention is to provide a method for exposing semiconductor materials using a mercury lamp, which can be carried out stably.

[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 with mercury 0 continuously lit, and the In the first step, the original LD conductor wafer material tII that is emitted from the mercury lamp is exposed to the discharge current waveform of the mercury lamp. Thickness of overshoot and undershoot g1r10%
One method of exposing a semiconductor wafer material using a mercury lamp is characterized in that switching between the first step and the second step is carried out under the conditions defined below.

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

An embodiment of the present invention? For example, as shown in Fig. wJ1, power is constantly supplied to the mercury lamp 1 housed in the exposure device for the conductor material 1, so that it is in a continuous lighting state, and then the second As shown in the figure, an example of the power consumption waveform, by controlling the power supplied to the mercury lamp l,
The first step A and 7Xf [J] where the power consumption of the mercury lamp is at a high level, e.g., about L3 to 2.5 times the rated power consumption, and the power consumption of the mercury lamp is at a low level, e.g. The second step B and t are at a similar level.
Repeating the first step A [in periodic intervals of 9 times], the semiconductor wafer material z is exposed to light emitted from the mercury lamp l.
v1 yuan. In FIG. 1, 3 is a power supply circuit for driving the mercury lamp 1, 4 is a shutter for cutting off the source of the mercury lamp 1, 5, 6.7 are reflectors, 8 is an integrator, 9 is a filter, Lot! Condenser lens, 1lfl photomask, 12txa small lens, reduction degree is normal] ~
It can be pronounced as T.

For regulation of exposure amount? In this case, by setting the shutter 4 open time appropriately, the conductor wafer material #+
The exposure amount applied to the baseless portion of the plate in step 2 is adjusted to the required specified value. That is, the first step A where the power consumption is at a high level
Therefore, it is assumed that the mercury lamp 1 is turned on (114), and the shutter 4 is left open for a set time, so that the total amount of exposure is regulated. Then, in the second step B in which the power consumption is reduced to a low level, the mercury lamp is turned on, and the shutter 4 is closed throughout this period.

The repetition of the first step A and the second step B is
The conductors 9 are interlocked with each other in relation to the stepwise movement of the material 2.

That is, as shown in FIG. 3, the exposed part of the conductor 1 - material 2 It is divided into a large number of micro-areas P arranged in rows and columns, and each of these micro-areas P is sequentially moved in a stepwise manner to an exposure position and exposed while being held still at that position. By opening and closing the shutter 4, one exposure is completed and one minute area PI of the conductor wafer material is exposed.
The C pattern is printed. Then, while the shutter 4 is closed, the micro area Pi to be exposed next is moved by 1 step to the exposure source position, and the exposure is repeated in the same manner.

In this way the first steps A and #! Exposure is performed in conjunction with step B of step 2, the opening/closing operation of the shutter 4, and the step movement of the conductor wafer material 2. However, the switching between step A of step A and step B of step 20 is performed by the driving power supply circuit section. 3, as shown in WL4 Figure 9, the mercury lamp l
The discharge current waveform is set such that the magnitude of overshoot 11 and undershoot I2 in 8 is not more than klO%.

However, the magnitude of the overshoot 11 is 9 VC when the discharge current rises from the low level to the high V pel in FIG. The size H of the portion hl that protrudes upward from the flat portion 11 at the high level from the low level to the high level.
The large undershoot I2 is good in terms of the ratio to
As a specific means for specifying the size of the low level (f flat, large ′@gh2 of the portion protruding downward from S+2 to 10% or less), there is no particular limitation, and known power sources may be used. It is sufficient if the circuit configuration is adopted.The large bias of the overshoot 11 and undershoot 12 is 10.
If it exceeds %, the tm wear of the mercury lamp will be large and the usable time of the mercury lamp will be considerably shortened.

FIG. 5 shows an example of a specific configuration of the mercury lamp l.

101 is a quartz glass enclosure, 102A and 102B are caps, and 103 and 104 are each 1! Other rod, 105°10
6 is an anode body and @pole body, respectively. Mercury is sealed inside the envelope 101, and the amount of mercury sealed is determined to be such that the mercury does not condense when the mercury lamp 1 is turned on in the second step BKg.

As shown in an enlarged view in FIG. 6, the anode body 105 has a large-diameter cylindrical body 51 and a tapered end surface 52 extending from the C body 51 with a flat tip end. The cathode body 106 is composed of a columnar part 61 and a tip part 62 formed in a cone shape and extending from the columnar part 61, as shown in an enlarged view in FIG. .

An example of the specific design of such a mercury lamp 1 is as shown below.
) Outer diameter D14 of the anode body shape trunk 51. Diameter D2 of CJ tip face 52 2. (1+a+
Opening angle α of tip portion 53 90 degrees Outer diameter D5 of cathode body shape columnar portion 61 2.0Illl
! Distance between electrodes L: 3.0■Pressure inside the enclosure when the lamp is lit at rated power consumption: 13 atm Using a mercury lamp with such a configuration, and based on the method described above, exposure of semiconductor wafer material was carried out under the following conditions: As a result, the initial exposure amount was stably obtained over a long period of about 600 hours, and the semiconductor wafer material was successfully exposed.

Time interval of first step A 400m5ec compilation 2
Time interval of step B: 400 m5ec First step A It was zesty.

Second step BT/C: 500W [undershoe] I from the initial power consumption of F+5 until 600 hours have elapsed
Exposure was carried out in the same manner as above, except that various values were changed as shown in the first surface pressure water of the size of 2 below. As shown in Table 1, in cases where the mercury lamp exceeds this value, the usable time for practical use of the mercury lamp is extremely short.

Table 1 [Operations and Effects of the Invention] As explained in detail above, according to the method of the present invention, the following effects are achieved.

+11 When the radiation source of the mercury lamp is not used for m sources, the mercury lamp is turned on from the second step T/C when the power consumption of the mercury lamp is at a low level, so the power wasted by the mercury lamp is reduced by a large mK. Can the shunter overheat damage? In addition, mercury lamps can be used in the second step with low power consumption (designed accordingly), and in the first step the mercury lamps have a high power consumption. Therefore, the necessary exposure amount can be obtained at this time, and therefore, it can be carried out using a mercury lamp that is smaller than that used for exposure of semiconductor wafer materials. The cost is small, and the manufacturing cost and undershoot of semiconductor devices are ultimately suppressed to below kIO%, while the first step has a high level of power consumption and the second step has a low level of power consumption. Since the switching is performed 7 times, the premature wear of the electrodes that occurs when the overshoot and undershoot exceed 10% does not occur, and therefore the amount of light emitted from the mercury lamp in the first step is maintained at the same level as the initial one. As a result, by repeating the first step and the second step at short time intervals, it is possible to fully expose the semiconductor material with a stable amount of emitted light over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram schematically showing an example of an exposure apparatus;
The second reason is an explanatory diagram showing an example of the waveform of the power consumption of a mercury lamp that changes due to the repetition of the first and second steps, Figure 3 is an explanatory diagram showing a cow conductor erunder chute, and Figure 5 An explanatory diagram showing an example of the lamp mercury illusion, Figure 6 is the 5th
The mercury lamp shown in the figure can be enlarged and shown as an explanation diagram for industrial water. l...Mercury lamp 2...Semiconductor Unino・
-Material 3...Drive power supply circuit section 4...Shutter 5.6.7・Reflector 8...Integrator 9・
Filter 10... Condenser lens 1
1... Photomask 12... Reduction lens 10
1... Enclosure 102A, 102B... Base 103.104... Electrode rod 105... Anode body 5
1...Body part 52...Front end surface 53...Tip part 106...Cathode body 61 -Columnar part
62...Tip #1 Figure Figure 4 B1p (msec)

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 for exposing a semiconductor wafer material with light emitted from the mercury lamp in the first step, wherein the overshoot and undershoot in the discharge current waveform of the mercury lamp are defined to be 10% or less A method for exposing semiconductor wafer material using a mercury lamp, characterized in that a first step and a second step are switched.