JPH09160219A - Optical element and exposure device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical element capable of forming a pattern with high resolution and high contrast and an exposure device using the same by forming a periodic pattern having period near to exposure wavelength in the longitudinal direction of the pattern with respect to the pattern. SOLUTION: A reticle 19 is provided with the periodic fine pattern 2 having the period nearly the same as that of the exposure wavelength in the longitudinal direction of the circuit pattern 1 of an LSI performing image formation. Since the pattern 2 is formed in a direction crossing at a right angle with the longitudinal direction of the pattern 1, the mainly polarizing direction of light passing through the pattern 2 coincides with the longitudinal direction of the pattern 1. By making use of the characteristic of the pattern 2 of the exposure wavelength order, optimum polarizing condition can be obtained for the individual circuit pattern 1 on the reticle 19. As a result, the contrast in the case of image forming is improved, and the improvement of depth of focus and limit image performance can be attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element in the formation of a pattern forming a circuit such as an IC or LSI and an exposure apparatus using the same, and particularly to a fine wafer on a wafer (substrate) for manufacturing a semiconductor element. It is suitable for forming a pattern.

[0002]

2. Description of the Related Art With the progress of miniaturization of semiconductor devices, new image forming techniques such as phase shift and modified illumination have been developed, and the results of the new image forming techniques have been successively introduced on the exposure apparatus side. Against this background, since the limit of the resolution in the conventional simple optical system has become clear, it has become necessary to seek new possibilities such as handling the phase.

Polarization has been known as a parameter which has been known to be effective in an exposure apparatus for manufacturing semiconductor devices but has not been actively used. A lot of literature has been written about the effect of polarization, and Y.Unno: "Pola is one example.
rization effect of illumination light ", Proc.SPIE
1927 "Optical / Laser Microlithography VI" (1993) pp.
There are 879-891. It has also been clarified from analysis and experimental results that the effect of polarization is great especially when the angle between the image forming lights is large, for example, for an oblique incidence optical system or a Levenson type phase shift mask.

[0004]

With the demand for a new imaging technique as described above, how to incorporate a new parameter into the apparatus in a practical form has become a major issue. However, with respect to polarized light, there is a problem in that there is no good polarizing element in the ultraviolet region where exposure is actually performed. Also,
The patterns that make up the actual LSI circuit are often formed mainly in the X and Y directions, which are parallel to the reticle outline, but some patterns include ± 45 ° directions. is there. Since the patterns in these various directions are complicatedly arranged in the reticle, it is necessary to easily create the polarization state in any direction according to the direction of the pattern. Conventionally, there has been a problem that it is difficult to obtain an optimum illumination state at a place or place depending on the directionality and fineness of each pattern. An object of the present invention is to provide an optical element capable of forming a pattern with high resolution and high contrast, and an exposure apparatus using the same.

[0005]

SUMMARY OF THE INVENTION The present invention controls the state of light that forms an image corresponding to the actual LSI circuit pattern.
Therefore, the feature is that a periodic fine pattern having a fine structure is applied to the pattern itself or its equivalent surface. As a result, the light incident on the reticle (optical element) on which the circuit pattern is formed can have its polarization state optimized, and can form an image with higher contrast. In addition, by arranging the fine pattern on the reticle or on the equivalent surface of the reticle, it is possible to select the polarization depending on the pattern and the illumination method depending on the configuration, thereby improving the imaging performance. ing.

Specifically, the optical element of the present invention comprises: (1-1) In an optical element having a pattern to be transferred, in the vicinity of the exposure wavelength in the longitudinal direction of the pattern. The feature is that a periodic pattern having a period of is formed.

The exposure apparatus of the present invention is: (2-1) In the exposure apparatus for transferring the pattern onto a substrate by using an optical element having a pattern to be transferred, the illumination optical of the exposure apparatus. An optical member having a fine periodic pattern having a period near the exposure wavelength used in the exposure apparatus in a direction equivalent to the longitudinal direction of the pattern in the vicinity of the conjugate plane of the optical element existing in the system. It is characterized by having placed.

(2-2) In an exposure apparatus for transferring the pattern onto a substrate by using an optical element on which a pattern to be transferred is formed, the optical device existing in an illumination optical system of the exposure apparatus A function of controlling the illumination state of the optical element and an optical member having an alignment mark for alignment can be arranged in the vicinity of the conjugate plane of the element, and the alignment mark of the optical member is provided in the illumination system. Is equipped with a reference mark and an observation system corresponding to, and a position adjusting system of the optical member.

(2-3) The optical member has a fine periodic pattern having a period in the vicinity of the exposure wavelength used in the exposure apparatus in a direction equivalent to the longitudinal direction of the pattern to be transferred.

(2-4) In an exposure apparatus for transferring the pattern onto a substrate by using an optical element on which a pattern to be transferred is formed, the optical element existing in an illumination optical system of the exposure apparatus. A fine periodic pattern having a period near the exposure wavelength in a direction equivalent to the longitudinal direction of the pattern in the vicinity of the conjugate plane of the element, and a direction parallel to the longitudinal direction of the pattern. It is characterized by arranging an optical member in which the periodic pattern (1) is arranged.

(2-5) Scan type exposure for exposing while scanning the optical element and the substrate when the pattern is transferred onto the substrate by using the optical element on which the pattern to be transferred is formed. In the apparatus, an optical member for controlling an illumination state of the optical element is arranged in the vicinity of a conjugate plane of the optical element existing in the illumination optical system of the exposure apparatus, and the optical element and the substrate are synchronized with each other in synchronization with scanning. It is characterized by scanning the optical member.

(2-6) A scanning type exposure apparatus for exposing and transferring the pattern on the optical element having the pattern to be transferred onto the substrate while scanning the optical element and the substrate. In, in the vicinity of the conjugate plane of the optical element existing in the illumination optical system of the exposure apparatus, an alignment mark for alignment and an optical member having a function of controlling the illumination state of the optical element are arranged. In addition, a reference mark corresponding to the alignment mark of the optical member, an observation system, a position adjusting system for the optical member, and a mechanism for scanning the optical member in synchronization with the scanning of the optical element and the substrate are provided. It is characterized by having done.

(2-7) In an exposure apparatus that uses a linearly polarized light source as a light source for exposure, a polarization-selective optical member exists in the exposure apparatus, and the light source is the light source with respect to the optical member. It is characterized in that the light from is incident as non-linearly polarized light.

In the exposure method of the present invention, (3-1) a fine periodic pattern having a cycle near the exposure wavelength used by the exposure apparatus in a direction equivalent to the longitudinal direction of the pattern to be transferred by the optical member is formed. It is characterized by having.

(3-2) When an optical device having a pattern to be transferred is used to transfer the pattern onto a substrate by an exposure device, the pattern exists in the illumination optical system of the exposure device. It is characterized in that an optical member for controlling the illumination state of the optical element is arranged in the vicinity of the conjugate surface of the optical element to perform exposure.

(3-3) When an optical device having a pattern to be transferred is used to transfer the pattern onto a substrate by an exposure device, the pattern exists in the illumination optical system of the exposure device. In the vicinity of the conjugate plane of the optical element, a fine periodic pattern having a period in the vicinity of the exposure wavelength in a direction equivalent to the longitudinal direction of the pattern, and a parallel pattern equivalent to the longitudinal direction of the pattern. It is characterized in that an optical member having a directional periodic pattern is arranged.

(3-4) The pattern on the optical element on which the pattern to be transferred is formed is exposed on the substrate while scanning the optical element and the substrate using a scanning type exposure device. At the time of transfer, an optical member for controlling the illumination state of the optical element is arranged in the vicinity of the conjugate surface of the optical element in the illumination optical system of the exposure device, and the optical element is synchronized with the scanning of the optical element and the substrate. The feature is that the member is scanned.

(3-5) In an exposure method for transferring a pattern onto a substrate by using an exposure apparatus that uses a light source for exposure having linear polarization, a polarization-selective optical member is provided in the exposure apparatus. Light existing from the light source is incident on the optical member as non-linearly polarized light.

The semiconductor device manufacturing method of the present invention is either the exposure apparatus having the above-mentioned constitutions (2-1) to (2-7) or the exposure method having the constitutions (3-1) to (3-5). It is characterized by being manufactured using one.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view of the essential portions of Embodiment 1 of the optical element of the present invention, showing an example in which a fine structure is applied to a reticle. In the figure, 19 is a reticle (optical element), 1 is a circuit pattern (pattern), and 2 is a periodic fine pattern. It is generally known that as the pattern becomes finer, more complicated light control is required, and in particular, polarized light plays an important role. For that purpose, it is desirable that the imaging light has an electric field vector in a direction parallel to the longitudinal direction of the pattern. The direction of the electric field vector is customarily defined as the polarization direction. In the present embodiment, the circuit pattern 1 itself on the reticle 19 is provided with the fine structure 2 to control the polarized light and increase the polarization component desirable for image formation to improve the image formation performance.

The reticle 19 shown in FIG. 1 is provided with a fine grating (periodic fine pattern) 2 having a period about the same as the exposure wavelength in the longitudinal direction of a circuit pattern 1 of an LSI for forming an image. It is AKWong e that the transmittance of the pattern differs depending on the polarization direction in a fine pattern similar to the exposure wavelength.
t al .: "Polarization Effects in Mask Transmission",
Proc.SPIE 1674 "Optical / Laser Microlithography V
(1992) pp.193-200. In the conventional approximation theory called the scalar theory, the transmittance of the pattern is independent of the polarization direction. However, the pattern is miniaturized to the same extent as the exposure wavelength, and the behavior of light is strictly controlled.
Returning to Maxwell's electromagnetic field equation, it is revealed that the transmittance of the pattern differs depending on the polarization direction. For example, if one rectangular pattern is considered and its width direction is made smaller, it is understood that the light in the polarization direction parallel to the longitudinal direction has a low transmittance and the light in the orthogonal polarization direction has a good transmittance. There is.

On the other hand, in the image formation of the pattern through the projection optical system, it is desirable that the polarization direction is parallel to the longitudinal direction of the circuit pattern of each LSI. The reticle shown in FIG. 1 is characterized in that a fine pattern 2 having a cycle similar to the exposure wavelength is periodically formed in the longitudinal direction 1a of an LSI circuit pattern 1. Since the fine pattern 2 is formed in a direction orthogonal to the longitudinal direction of the circuit pattern 1, the main polarization direction of the light passing through the fine pattern 2 is orthogonal to the direction of the fine pattern. It means that it coincides with the direction, that is, the longitudinal direction of the circuit pattern 1. As described above, the polarization direction parallel to the longitudinal direction of the circuit pattern matches the polarization direction advantageous for pattern formation on the wafer.
Therefore, as shown in FIG. 1, a fine pattern 2 having the same wavelength as the exposure wavelength is provided in conformity with the circuit pattern 1 on the reticle to improve the image contrast on the wafer. The fine pattern 2 is too fine to be transferred onto the wafer.
In this embodiment, half of the exposure wavelength is set for lithography using light from a KrF excimer laser having a wavelength of 248 nm.
A 0.12 μm line and space is used as the fine pattern 2 on the reticle.

In many cases, the actual LSI circuit pattern is mainly formed with patterns in the X and Y directions parallel to the outer shape of the reticle, but in order to increase the degree of integration, it may be in any direction such as ± 45 °. Pattern may also be included. In the reticle of this embodiment, by setting the fine patterns individually at right angles to the longitudinal direction of each circuit pattern, the optimum polarization state can be selected for any pattern, and Even if the patterns in various directions are mixed, it is possible to cope with them by selecting the direction of the fine pattern for each pattern.

Further, the fine pattern as in this embodiment is set to L
If it is provided for the SI circuit pattern, the transmittance of the transmission part of the pattern is reduced as compared with the case where no fine pattern is provided. The effect of polarization is remarkable for fine patterns near the resolution limit, and is less effective for coarse patterns, but the effect of polarization is small in the reticle plane. In order to keep the transmittance of the
The fine pattern is applied to all the patterns on the reticle while maintaining the same periodicity, regardless of the fineness of the line width of the pattern. In FIG. 1, a periodic pattern having a line width around the exposure wavelength is arranged even for a rough pattern.

Although FIG. 1 shows application to a normal amplitude type reticle, if the optical element of the present invention is applied to a phase shift type reticle, a larger effect can be obtained. The effect of polarization becomes more significant as the angle formed by the diffracted lights that contribute to image formation on the wafer surface increases. In the Levenson type, the 0th-order light disappears and images of ± 1st-order rays are formed, so that the effect of polarization appears more greatly in the region where the expected fine pattern is resolved than in the amplitude type. The present invention is most effective when applied to a reticle.

FIG. 2 is a schematic view of a main part of a Levenson type phase shift reticle. In FIG. 2, 201 is a phase shift film.

FIG. 3 is a schematic view of the essential portions of Embodiment 2 of the exposure apparatus of the present invention. This figure shows an example in which polarization control is performed on the optical conjugate plane of the reticle. Forming a fine pattern on the reticle itself requires a lot of time for inspection and the like as well as the production of the reticle, and is costly. Therefore, in this embodiment, the same effect is realized by inserting an optical member for controlling polarized light in a position conjugate with the reticle, specifically, in the illumination system. In the figure, 10 is an ultra-high pressure mercury lamp as a light source, 11 is an elliptical mirror for collecting light, and 12 is a shutter. Reference numeral 12 'is a shutter drive motor, 13 is a condenser, 14 is a wavelength selection filter, and 15 is an optical integrator. Reference numeral 16 is a condenser for condensing the light emitted from the integrator 15, and 17 is a masking blade arranged on the conjugate plane with the reticle 19. The light that has passed through the masking blade 17 receives the subsequent condenser system 18, 1
The reticle 19 is illuminated by 8 '. The circuit pattern on the illuminated reticle 19 is imaged on the wafer 52 held by the wafer chuck 53 by the projection optical system 51.
It is applicable to this embodiment that the condenser 13 is replaced or zoomed to adjust the amount of light, the condenser 16 is adjusted to adjust the illuminance distribution, and the like.

As described above, the effect of polarization becomes more remarkable when the angles of the lights that contribute to image formation are large. Therefore, when an amplitude reticle is used as the reticle 19, polarized light is most effective when modified illumination, that is, oblique incidence illumination is performed. Here, optical integrator 1
A case in which a replaceable diaphragm 21 is provided after 5 and quadrupole illumination is performed will be described. Reference numeral 21 'is a drive system for replacing the diaphragm. The following description is the same even when different apertures are selected and annular illumination is performed.

In this embodiment, the polarization selection element (optical member) 22 is inserted at the position of the conjugate plane 17 of the reticle in the illumination system. The polarization selecting element 22 corresponds to the circuit pattern on the reticle 19 and transmits the optimum polarized light for the pattern. FIG. 4 shows the reticle 19 used in FIG. 3 and the polarization selection element 22 corresponding to the reticle 19. For the sake of simplicity, both have the same size and the inversion relationship of the image is also written, but
Actually, the relative relationship between the two patterns is capacitor system 1
8,18 'magnification, reticle 19 and masking blur
It is determined from the inversion relationship of the image by the mirror arranged between the dots 17.

For example, it is assumed that there is a vertical LSI circuit pattern 31 in the area A on the reticle 19. In this case, in the area A1 on the polarization selection element 22 corresponding to the area A, a fine periodic pattern 31 'having an exposure wavelength order is formed in the lateral direction orthogonal to the circuit pattern 31. As the pattern 31 ′, for example, i-line exposure (365n
In the case of m), a line and space of 0.18 μm, which is half the wavelength, is used. That is, the cycle of the fine pattern matches the exposure wavelength. If there is a horizontal circuit pattern 32 in another region B of the reticle 19, a pattern 31 'is formed in the region B1 on the polarization selection element 22 corresponding to the region B.
Fine periodic pattern 32 'with exposure wavelength order similar to
Are formed in the vertical direction orthogonal to the circuit pattern 32. The polarization selectivity of the fine periodic pattern with the exposure wavelength order is as described above. The fine periodic pattern of the exposure wavelength is too fine for the optical system to resolve,
Therefore, it is not transferred onto the wafer 52 as a pattern. In FIG. 4, an example is shown in which the fine periodic pattern of the area A1 corresponding to the portion without a pattern at the lower right of the area A is omitted, but in the area A1 only the polarized light is selected. The fine periodic pattern may not be omitted.

In the drawing, the vertical and horizontal patterns are explained, but +
For a 45-degree pattern, a -45-degree pattern may be used.For example, a fine periodic pattern with a wavelength order should be formed in the direction orthogonal to the pattern at any angle. Good.

Since the pattern 31 'may be formed continuously over the entire area corresponding to the pattern 31, as in the first embodiment, the pattern is formed for each circuit pattern of each LSI.
It is easier to create than creating Further, in the case where the polarization selection element 22 is in a contracted relationship with the reticle,
Since the area of the region for forming the pattern of the exposure wavelength order is smaller than that in the case where the fine pattern is directly written on the reticle, it becomes a factor of reducing the cost. In this case, the line width of the fine periodic pattern that selects the polarized light is determined by the relationship with the exposure wavelength, so even if the area is reduced, the same reduction ratio is not applied and the line width or period is always close to the exposure wavelength. is there.

Since the polarization selection element 22 for determining the polarization is formed corresponding to the reticle 19 and arranged near the position of the masking 17, the individual patterns 3 on the reticle 19 are arranged.
1 is illuminated with an optimal polarization state according to its directionality.
Therefore, there is an alignment relationship between the reticle 19 and the polarization selection element 22. A reticle alignment mark 33 is originally formed on the reticle to be attached to the stepper, and the alignment mark 33 is attached to a reference mark 34 which is attached in the vicinity of the reticle or on the wafer stage in advance. Aligned to. The reticle alignment mark 33 and the reference mark 34 are observed by the observation system 39, and the reticle 19 is set on the reference mark 34 by an adjusting mechanism (not shown). On the other hand, the polarization selection element 22
Similarly, the alignment mark 35 is attached. The polarization selection element 22 is aligned by aligning the alignment mark 35 with a reference mark 36 in the illumination system. Therefore, the alignment mark 3 is placed in the illumination system.
5 and a reference mark observation system 37 for observing the reference mark 36, and a position adjusting mechanism 38 for aligning the polarization selection element 22. Each time the reticle 19 is exchanged by a transport system (not shown), the polarization selection element 22 is also exchanged by a transport system (not shown), and the position adjustment mechanism 38 adjusts the position based on the observation result of the reference mark observation system 37. There is.

FIG. 5 is a schematic view of the essential portions of Embodiment 3 of the present invention. In the present embodiment, an example in which the illumination method and the polarization method are selected at the same time is shown. The specific system configuration is shown in FIG.
The second embodiment is almost the same as the second embodiment, and the same components are designated by the same reference numerals. The difference between FIG. 5 and FIG. 3 is that the diaphragm 21 behind the optical integrator 15 has a condition that σ indicating the coherence of the illumination system is small, and an optical member installed in the masking blade portion. The difference is that 22 'has other structures in addition to the fine periodic pattern of the exposure wavelength order. As the structure of the optical member 22 ', there is a structure provided with a phase shift film or a structure provided with amplitude type grating. The newly added pattern plays the role of controlling the angle at which the reticle is illuminated. Here, as a typical example, the one in which the phase shift type grating is arranged will be described.
The optical mark 22 'is also provided with the alignment mark 35 as in the previous example.

FIG. 6 shows the relationship between the reticle 19 and the corresponding optical member 22 'as in FIG. The circuit pattern 3 of the vertical LSI in the area A on the reticle 19
1 is present, in the area A2 on the optical member 22 'corresponding to the area A, a fine periodic pattern 31' having an exposure wavelength order is formed in the lateral direction orthogonal to the circuit pattern 31. At the same time, a phase grating 41 is formed in the vertical direction. The vertical grating 41, which is parallel to the longitudinal direction of the circuit pattern 31, acts to eliminate the 0th order light and generate ± 1st order diffracted light as shown in FIG. 7, and as a result, on the reticle. The pattern area A is illuminated so as to satisfy the optimum illumination condition of the modified illumination. That is, the pitch of the phase grating 41 is set so as to obtain the optimum illumination condition.

Lateral LS in another area B of the reticle 19
When there is a circuit pattern 32 of I, in the area B2 on the optical member 22 'corresponding to the area B, a fine periodic pattern 32' of the exposure wavelength order is perpendicular to the circuit pattern 32 in the vertical direction. And the phase grating 42 is formed in the lateral direction orthogonal to the above. The lateral grading 42 also produces diffracted light as schematically shown in FIG. 7, and also illuminates the pattern area B on the reticle so that the optimum illumination condition in the modified illumination is obtained. The phase type gratings 41 and 42 have the periodic patterns 31 ′ and 3
Since the period may be rougher than 2'and transferred onto the wafer, it may be placed at a position slightly defocused from the conjugate surface of the reticle and arranged so as not to be transferred.

The phase gratings 41 and 42 shown in FIG.
Is a cross-sectional view of the reticle, showing a phase shift film formed on the glass surface of the reticle.

The irradiation angle can be selected not only by the phase grating but also by using the phase gratings 41 and 42 with the amplitude grating. Also in this case, the polarization direction is selected by the fine periodic patterns 31 'and 32', and the illumination angle is selected by the phase type gratings 41 and 42. Therefore, illumination according to the reticle area can be performed. it can.

FIG. 8 is a schematic view of the essential portions of a fourth embodiment in which the present invention is applied to a scanning type exposure apparatus. In the case of the scanning type, the reticle 19 and the wafer 52 move relative to the light of the illumination system. Specifically, the illumination system is fixed and the reticle 19 and the wafer 52 scan. The present invention can be similarly applied to this case.

Also in FIG. 8, the same members as those described above are designated by the same reference numerals. The apparatus has an illumination system, a reticle system, a projection optical system, and a wafer system. The illumination system and the projection optical system 51 are fixed, and the reticle 19 and the wafer 52 are synchronized in a speed relationship according to the reduction ratio of the projection system. Scanning.
The reticle 19 is placed on the reticle scanning stage 54 and the wafer 5
2 is mounted on a wafer scanning stage 55, and both scanning stages are precisely position-controlled by a laser interferometer.

In order to apply the illumination light having the desired polarization state or the desired illumination angle to each part of the reticle to be scanned, the optical member 22 described so far.
The feature of this embodiment is that (22 ′) is scanned in synchronization with the scanning of the reticle. 56 is the optical member 22 (2
2 ') is a scanning stage for mounting. Scanning stage 56
Can also be used to scan the masking blade 17 during exposure. Reticle 19 and optical member 22 (2
If scanning is performed while maintaining the relative relationship between 2 '), desired illumination light can be applied to the reticle 19, and the imaging performance can be improved. As in the present embodiment, the optical element that is synchronously scanned with the reticle 19 or the wafer 52 is not limited to the selection of the polarization state of the illumination light but also to an optical member having other characteristics, for example, an optical member for controlling the angle characteristic. Is also applicable. In this embodiment, the reference mark 34 for setting the reticle in the apparatus is arranged on the wafer scanning stage. The alignment of the optical member 22 (22 ′) with respect to the device is the same as in the previous embodiment.

Although an example in which an ultra-high pressure mercury lamp is used as a light source has been shown so far, the present invention can be similarly applied to a light source having linear polarization such as an excimer laser. When using a linearly polarized light source, in order to be generally compatible with patterns having various directivities, it is necessary to reach a fine periodic pattern that determines the main direction of polarized light. It is necessary to make the polarization direction non-linear. Therefore, regardless of whether it is on the reticle or in the vicinity of the conjugate plane with the reticle, the position and the rarity of the fine periodic pattern exist.
An optical member such as a λ / 4 plate that controls the polarization state is placed between the light sources, or the laser beam is split by a beam splitter and the polarization direction is rotated to integrate the beam again. It is necessary to have a configuration.

FIG. 9 shows a flow of manufacturing a semiconductor device (a semiconductor chip such as an IC or an LSI, or a liquid crystal panel or a CCD).

In step 1 (circuit design), a semiconductor device circuit is designed. Step 2 is a process for making a mask on the basis of the circuit pattern design.

On the other hand, in step 3 (wafer manufacturing), a wafer is manufactured using a material such as silicon. Step 4
The (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the prepared mask and wafer.

The next step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer produced in step 4, and includes an assembly process (dicing and bonding) and a packaging process (chip encapsulation). And the like.

In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 10 shows a detailed flow of the wafer process. Step 11 (oxidation) oxidizes the wafer's surface. Step 12 (CVD) forms an insulating film on the wafer surface.

In step 13 (electrode formation), electrodes are formed on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. Step 15
In (resist processing), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the above-described exposure apparatus to print and expose the circuit pattern of the mask onto the wafer.

In step 17 (development), the exposed wafer is developed. In step 18 (etching), parts other than the developed resist are scraped off. In step 19 (resist stripping), the resist that has become unnecessary after the etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer.

By using the manufacturing method of this embodiment, it is possible to easily manufacture a highly integrated semiconductor device which has been difficult to manufacture in the past.

[0052]

As described above, according to the present invention,
By utilizing the characteristics of the fine periodic pattern of the exposure wavelength order, the optimum polarization state is provided for each individual pattern on the reticle. As a result, the contrast at the time of image formation is improved, the depth of focus is improved, and the marginal image performance is improved.

Further, according to the present invention, the exposure method and apparatus for performing the illumination compatible with the phase shift technique and the modified illumination technique by selecting the polarization state and creating the optimal illumination condition according to each pattern on the reticle. Are offered.
Further, the present invention can be realized by the reticle itself, or can be realized by a countermeasure on the exposure apparatus side with respect to the conventional reticle. Further, the present invention can be applied equally to a stepper or a scanning type exposure apparatus and has a wide range of applications, and can exert a great effect in the lithographic area where performance is pursued to the limit.

[Brief description of the drawings]

FIG. 1 is a reticle according to a first embodiment of the present invention.

FIG. 2 is a Levenson-type phase shift reticle to which the present invention is applied.

FIG. 3 is an exposure apparatus according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a pattern relationship between the reticle and the optical element of the present invention.

FIG. 5 is an exposure apparatus according to a third embodiment of the present invention.

FIG. 6 is a diagram showing a pattern relationship between the reticle and the optical element of the present invention.

FIG. 7 is a diagram showing angle control by the optical element of the present invention.

FIG. 8 is a scanning exposure apparatus according to a fourth embodiment of the present invention.

FIG. 9 is a flowchart of a method for manufacturing a semiconductor device of the present invention.

FIG. 10 is a flowchart of a method for manufacturing a semiconductor device of the present invention.

[Explanation of symbols]

 1 LSI circuit pattern 2 Periodic fine pattern 10 Ultra-high pressure mercury lamp 11 Elliptical mirror 12 Shutter 12 'Shutter drive system 13 Condenser lens system 14 Wavelength selection filter-15 Optical integrator 16 Condenser lens system 17 Masking blade 18, 18 'Condenser lens system 19 Reticle 21 Aperture 21' Aperture drive system 22 Polarization selection element 22 'Polarization and angle selection element 31 Circuit pattern of LSI on reticle 31' 31 Orthogonal Fine periodic pattern 32 Fine circuit pattern 32 'of the LSI on the reticle 32' Fine pattern 32 orthogonal to the pattern 32 Reticle alignment mark 34 Device side reference mark 35 22 (22 ') alignment mark 36 Reference Mark in Illumination System 37 Reference Mark Observation System 38 22 (22 ' Position adjusting mechanism 39 Observation system 41 Phase grating orthogonal to 31 '42 Phase grating orthogonal to 32' 51 Projection optical system 52 Wafer 53 Wafer chuck 54 Reticle scanning stage 55 Wafer scanning step Scan Stage of 5622 (22 ')

Claims (24)

[Claims] 1. An optical element in which a pattern to be transferred is formed, wherein a periodic pattern having a period near the exposure wavelength is formed in the longitudinal direction of the pattern with respect to the pattern. And optical element. 2. A pattern transfer method, wherein the pattern of the optical element is transferred onto a predetermined surface by using the optical element of claim 1. 3. A Levenson phase shift type reticle using the optical element according to claim 1. Description: 4. A pattern transfer method, wherein the pattern of the optical element is transferred onto a predetermined surface using the reticle according to claim 3. 5. In an exposure apparatus for transferring the pattern onto a substrate by using an optical element having a pattern to be transferred, a conjugate of the optical element existing in an illumination optical system of the exposure apparatus. An exposure apparatus characterized in that an optical member having a fine periodic pattern having a cycle in the vicinity of the exposure wavelength used in the exposure apparatus in the direction equivalent to the longitudinal direction of the pattern is arranged near the surface. . 6. An optical element existing in an illumination optical system of the exposure apparatus when the pattern is transferred onto a substrate by an exposure apparatus by using an optical element having a pattern to be transferred. An exposure method comprising: arranging an optical member for controlling the illumination state of the optical element in the vicinity of the conjugate plane to perform exposure. 7. The exposure apparatus according to claim 6, wherein the optical member has an alignment mark for alignment. 8. The exposure method, wherein the optical member has a fine periodic pattern having a period near the exposure wavelength used in the exposure apparatus in a direction equivalent to the longitudinal direction of the pattern to be transferred. 9. In an exposure apparatus for transferring the pattern onto a substrate by using an optical element having a pattern to be transferred, a conjugate of the optical element existing in an illumination optical system of the exposure apparatus. A function of controlling the illumination state of the optical element in the vicinity of the surface and an optical member having an alignment mark for alignment can be arranged, and the illumination system corresponds to the alignment mark of the optical member. An exposure apparatus equipped with a reference mark, an observation system, and a position adjustment system for the optical member. 10. The exposure apparatus, wherein the optical member has a fine periodic pattern having a cycle in the vicinity of the exposure wavelength used in the exposure apparatus in a direction equivalent to the longitudinal direction of the pattern to be transferred. 11. An exposure apparatus for transferring the pattern onto a substrate by using an optical element having a pattern to be transferred, the conjugate of the optical element existing in an illumination optical system of the exposure apparatus. A fine periodic pattern having a period near the exposure wavelength in a direction equivalent to the longitudinal direction of the pattern in the vicinity of the surface, and a periodicity in a direction equivalent to the longitudinal direction of the pattern. An exposure apparatus having an optical member having a pattern arranged thereon. 12. An optical element existing in an illumination optical system of the exposure apparatus when the pattern is transferred onto a substrate by an exposure apparatus by using an optical element having a pattern to be transferred. A fine periodic pattern having a period near the exposure wavelength in a direction equivalent to the longitudinal direction of the pattern in the vicinity of the conjugate plane, and a period in a direction equivalent to the longitudinal direction of the pattern. An exposure method characterized in that an optical member having a characteristic pattern is arranged. 13. A scanning type exposure apparatus which exposes while scanning the optical element and the substrate when the pattern is transferred onto a substrate by using the optical element on which the pattern to be transferred is formed. An optical member for controlling the illumination state of the optical element is arranged in the vicinity of the conjugate surface of the optical element existing in the illumination optical system of the exposure apparatus, and the optical member is synchronized with the scanning of the optical element and the substrate. An exposure apparatus characterized by scanning. 14. The exposure apparatus according to claim 13, wherein the optical member controls a polarization state of illumination. 15. The optical member is composed of a fine periodic pattern having a period of the same order as the exposure wavelength used in the exposure apparatus in a direction equivalent to the longitudinal direction of the pattern. 15. The exposure apparatus according to claim 14, wherein: 16. The exposure apparatus according to claim 13, wherein the optical member controls an angular state of illumination. 17. The exposure apparatus according to claim 16, wherein the optical member is constituted by a periodic pattern which is equivalently parallel to the longitudinal direction of the pattern. 18. A fine periodic pattern in which the optical member has a periodicity in the vicinity of the exposure wavelength in a direction equivalent to the longitudinal direction of the pattern, and is equivalently parallel to the longitudinal direction of the pattern. 14. The exposure apparatus according to claim 13, wherein the exposure apparatus is composed of a periodic pattern in different directions. 19. A scanning type exposure apparatus for exposing and transferring the pattern on an optical element having a pattern to be transferred onto a substrate while scanning the optical element and the substrate. In the vicinity of the conjugate plane of the optical element existing in the illumination optical system of the exposure apparatus, an alignment mark for alignment and an optical member having a function of controlling the illumination state of the optical element are arranged, and It is equipped with a reference mark and an observation system corresponding to the alignment mark of the optical member, a position adjusting system of the optical member, and a mechanism for scanning the optical member in synchronization with the scanning of the optical element and the substrate. Characteristic exposure equipment. 20. When exposing and transferring the pattern on an optical element on which a pattern to be transferred is formed on a substrate while scanning the optical element and the substrate by using a scanning type exposure device. An optical member for controlling the illumination state of the optical element is arranged in the vicinity of the conjugate surface of the optical element in the illumination optical system of the exposure apparatus, and the optical member is scanned in synchronization with the scanning of the optical element and the substrate. An exposure method comprising: 21. In an exposure apparatus using a light source having linear polarization as a light source for exposure, a polarization-selective optical member exists in the exposure apparatus, and light from the light source is directed to the optical member. Is incident as non-linearly polarized light. 22. An exposure method for transferring a pattern onto a substrate by using an exposure apparatus using a light source for exposure having linear polarization, wherein a polarization-selective optical member exists in the exposure apparatus. An exposure method, wherein light from the light source is incident on the optical member as non-linearly polarized light. 23. Claims 5, 7, 9, 10, 11, 13
22. A method of manufacturing a semiconductor device, wherein a semiconductor device is manufactured using the exposure apparatus according to claim 19. 24. A method of manufacturing a semiconductor device, wherein a semiconductor device is manufactured by using the exposure method according to any one of claims 6, 12, 20, and 22.