CN1847986A - Thin film transistor, integrated circuit, liquid crystal display, method of producing thin film transistor, and method of exposure using attenuated type mask - Google Patents
Thin film transistor, integrated circuit, liquid crystal display, method of producing thin film transistor, and method of exposure using attenuated type mask Download PDFInfo
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- CN1847986A CN1847986A CN 200610071921 CN200610071921A CN1847986A CN 1847986 A CN1847986 A CN 1847986A CN 200610071921 CN200610071921 CN 200610071921 CN 200610071921 A CN200610071921 A CN 200610071921A CN 1847986 A CN1847986 A CN 1847986A
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Abstract
A method of producing a thin film transistor comprises irradiating a resist on a glass base plate with a ray from a light source through a mask and, thereafter, developing the resist to form contact holes, using an i-ray as the ray.
Description
Technical field
The present invention relates in the method that forms the effective method of film crystal on the glass substrate and use attenuated type mask (half-tone mask) that the photoresist on the glass substrate is exposed.
Background technology
Studied the method that makes TFT realize miniaturization in order to improve serviceability in the crystallinity thin film transistor (TFT) that on the glass substrate that the such display panel of display panels is used, forms (hereinafter referred to as " TFT ").
Glass substrate its thickness deviation in face that forms TFT is compared big significantly with the thickness deviation of semiconductor wafer.There is the so big thickness deviation of about 9 μ m (the about 9 μ m/100mm) thickness of slab of surfaceness or substrate itself (result from distribute) in this glass substrate in each limit is the foursquare area of 100mm.
When on glass substrate as described above, forming TFT, in the exposure of the photoresist on this glass substrate, and the exposure of the semiconductor devices manufacturing usefulness on the semiconductor wafer substrate is compared, needed dark depth of focus.That is, when making TFT realize that miniaturization is made,, then simultaneously must make the resolution of the exposure device that depth of focus does not shoal, TFT uses be about 1.5 μ m or 3 μ m now if improve the resolution of the exposure device that uses this moment.If this exposure device plans to make resolution than above-mentioned value height, then depth of focus shoals.
If resolution for example becomes the high image resolution that surpasses 0.8 μ m, then its depth of focus likens thickness deviation into the glass of the substrate that forms TFT to, promptly 9 μ m/100mm are shallow, can not form desirable resist pattern with the photoresist on the glass substrate.Under the situation that the photoresist on the glass substrate with big thickness deviation is exposed, because the difference of height of this photoresist face is big, so the optical system of exposure device is required darker focus.In the exposure process of making TFT, the formation operation of the contact hole that needs dark depth of focus is arranged.In the thickness of photoresist in this case, because usually the depth of focus during exposure is more shallow than the situation of line class pattern, so must work hard aspect not making that it shoals.
For example, the depth of focus of situation that forms the contact hole of 0.5 μ m is ± 0.9 μ m, and is very shallow.If form such contact hole for the manufacturing of the TFT that utilizes exposure device to carry out on glass substrate, to form,,, can not open the hole that connects photoresist so stay photoresist in the bottom of contact hole then owing to do not meet the regional wide of depth of focus.Its result for example can not obtain and the contacting of source region or drain region.
The contact hole of the exposure usefulness when in addition, forming TFT generally has foursquare shape.By the expose bight of the contact hole that the TFT that forms uses of photoresist is become circle in photoresist, become circular through such mask.Its result in above-mentioned exposure method, is difficult to form the hole that connects photoresist.
In exposure technique, put down in writing the situation that the phase shift mask (simply being called in this manual, " attenuated type mask ") of attenuated type improves resolution and depth of focus in to 40 pages the 39th page of non-patent literature 1.
In addition, put down in writing the technology that the resist that is used in the manufacturing procedure of using semiconductor wafer that the attenuated type mask uses semiconductor element or the semiconductive thin film that forms etc. on the glass substrate that display panel is used exposes at patent documentation 1.
[non-patent literature 1] puts down into ォ on February 25th, 9-system society distribution " ultra tiny process technology "
[patent documentation 1] spy opens the 2003-234285 communique
The numerical aperture NA that has put down in writing exposure device in the 40th page of non-patent literature 1 is 0.5, and coherence factor σ is 0.2.These values are the values of integrated circuit (LSI) usefulness as record in the non-patent literature 1.
Forming on the glass substrate that display base plate is used under the situation of TFT, consider that yield of unit time decides the per 1 time exposure area to the photoresist on the glass substrate, because this exposure area is big, so though resolution also is important, what more pay attention to is depth of focus.This is because as mentioned above, the thickness deviation of glass substrate is more a lot of greatly with the thickness deviation of Si wafer than LSI.
But, in non-patent literature 1, be not documented in the kind of the exposure optical system that makes depth of focus become darker usefulness in the exposure when forming TFT on the glass substrate that display base plate uses, the concrete numerical value of numerical aperture NA, coherence factor σ etc.
Also mainly contain the record with the Si wafer in the patent documentation 1, but be not documented in the concrete numerical value of kind, numerical aperture NA or the coherence factor σ etc. that obtain the exposure optical system that necessary depth of focus uses in the exposure when forming TFT on the glass substrate that display base plate uses about LSI.
As mentioned above, also do not know for the exposure of the resist that carries out on the glass substrate that display base plate is used, forming, particularly for the manufacturing of carrying out the contact hole that crystallinity TFT uses and obtain the kind of kind, the coherence factor σ of the such exposure light source of darker depth of focus, employed exposure optical system and numerical aperture NA etc.
Summary of the invention
The object of the present invention is to provide the method for manufacturing thin film transistor that can form the contact hole that connects resist fully.
Another object of the present invention is to provide the exposure method of phase shift mask of the attenuated type of the depth of focus that obtains appropriate depth in the exposure of having used the TFT that on being manufactured on the big substrate of the such thickness deviation of glass substrate that display base plate uses, forms to use.
It will be the operation that forms contact hole on the photoresist on this photoresist to the photosensitive material sheet on the uncompleted TFT that is forming on the glass substrate from the irradiate light of light source that the 1st to the 3rd manufacture method of the thin film transistor (TFT) relevant with the present invention all comprises through mask, use the i line as above-mentioned light.
In 1st manufacture method relevant with the present invention, aforementioned mask has a certain side's who is included in a plurality of transparent regions that formed the effective rectangle (comprising Long Circle and ellipse) of film crystal on the above-mentioned glass substrate and zone of opacity contact hole pattern, and the length dimension that a certain side of above-mentioned light transmissive region and light shaded areas has a long side direction is 1.4 times shape more than or equal to the length dimension of short side direction.
In 2nd manufacture method relevant with the present invention, aforementioned mask is the chrome mask of light-proofness, has a certain side's who is included in a plurality of light transmissive region that formed the effective rectangle (comprising Long Circle and ellipse) of film crystal on the above-mentioned glass substrate and light shaded areas contact hole pattern in addition.Multiplying power projection optical systems such as above-mentioned optical system is in addition, when k1 being decided to be coefficient with value of 0.40 to 0.43 and R is decided to be the length dimension of above-mentioned rectangular short side direction, have the numerical aperture NA that utilizes following formula (1) to obtain:
NA2＝k1×0.365/R……(1)
In 3rd manufacture method relevant with the present invention, aforementioned mask is the attenuated type mask, has a certain side's who is included in a plurality of light transmissive region that formed the effective rectangle (comprising Long Circle and ellipse) of film crystal on the above-mentioned glass substrate and light shaded areas contact hole pattern in addition.Multiplying power projection optical systems such as above-mentioned optical system is in addition, when k1 being decided to be coefficient with value of 0.34 to 0.41 and R is decided to be the length dimension of above-mentioned rectangular short side direction, have the numerical aperture NA that utilizes above-mentioned formula (1) to obtain.
In 1st manufacture method relevant, be that the contact hole that forms on the photoresist can have the rectangular flat shape that makes each bight become arcuation at least at above-mentioned photosensitive material sheet with the present invention.
In 2nd manufacture method relevant with the present invention, above-mentioned contact hole pattern is that the spacing of above-mentioned rectangular long side direction is 3 times a periodic pattern more than or equal to the length dimension of minor face for the spacing more than or equal to the length dimension sum of the size of the length on long limit and minor face and short side direction, and is configurable on a certain side of above-mentioned light transmissive region and light shaded areas.
In 3rd manufacture method relevant with the present invention, above-mentioned contact hole pattern is that the spacing of above-mentioned rectangular long side direction is 3 times a periodic pattern more than or equal to the length dimension of minor face for the spacing more than or equal to the length dimension sum of the size of the length on long limit and minor face and short side direction, and is configurable on a certain side of above-mentioned light transmissive region and light shaded areas.
1st to 3rd manufacture method relevant with the present invention also can comprise the operation of handling above-mentioned resist, form contact hole on above-mentioned resist.
The contact hole that forms on the above-mentioned resist of photosensitive material sheet can have the rectangular flat shape that makes each bight become arcuation at least.
The length dimension that the contact hole that forms on above-mentioned resist can have a long side direction is 1.4 times rectangular flat shape more than or equal to the length dimension of short side direction.
1st to 3rd exposure method relevant with the present invention all comprises through irradiate light that the attenuated type mask will incide on the optical system and will pass through above-mentioned optical system from the light of the exposure light source operation to the resist layer that is made of the photosensitive material on the glass substrate, use the i line as above-mentioned light, use in addition have utilize numerical aperture NA that above-mentioned formula (1) obtains etc. the multiplying power projection optical system.
In 1st exposure method relevant with the present invention, above-mentioned attenuated type mask has the line image that should form on above-mentioned resist layer.In addition, in formula (1), k1 is the coefficient with value of 0.41 to 0.44, and R is the width of the line that forms on above-mentioned resist layer.
In 2nd exposure method relevant with the present invention, above-mentioned attenuated type mask has the contact hole that should form on the above-mentioned resist layer on the above-mentioned glass substrate.In addition, in formula (1), k1 is the coefficient with value of 0.48 to 0.5, and R is the bore (or major diameter) in the hole that forms on above-mentioned resist layer.
In 3rd exposure method relevant with the present invention, above-mentioned attenuated type mask has the contact hole pattern that should form on the above-mentioned resist layer on the above-mentioned glass substrate, this contact hole pattern has 4 times contact hole arrangement pitches more than or equal to the diameter of contact hole.In addition, in formula (1), k1 is the coefficient with value of 0.48 to 0.5, and R is the aperture that forms on above-mentioned resist layer.
According to 1st to 3rd manufacture method relevant with the present invention, even also can obtain enforceable depth of focus in exposure process in the photosensitive material sheet that on the big substrate of thickness deviation, forms, can on photosensitive material sheet, form the fine contact hole that connects this photosensitive material sheet fully.
According to 1st to 3rd exposure method relevant, can obtain having used the exposure method of phase shift mask of the attenuated type of the depth of focus that can obtain appropriate depth on being manufactured on the big substrate of the such thickness deviation of glass substrate that display panel uses in the exposure of the resist layer that the TFT that forms uses with the present invention.
Description of drawings
Fig. 1 is the structural drawing that is illustrated in an embodiment of exposure device suitable in the enforcement of manufacture method relevant with the present invention and exposure method.
Fig. 2 is the figure that is illustrated in an embodiment of the attenuated type mask that is used in the exposure process used of the explanation manufacture method relevant with the present invention, and A is the planimetric map of attenuated type mask, and B is the sectional view of the attenuated type mask that obtains along the 2B-2B line among the A.
Fig. 3 is when the length that has changed the long limit that utilizes the square configuration mask pattern that the 1st embodiment of the present invention obtains is shown, the chrome mask of the relation of the depth of focus of this long limit and projection optical system and the performance diagram of attenuated type mask.
Fig. 4 be illustrate the exposure device that utilizes Fig. 1 that the 2nd embodiment of the present invention obtains etc. the performance diagram of relation of the numerical aperture of multiplying power projection optical system 26 and depth of focus.
Fig. 5 be illustrate the exposure device that utilizes Fig. 1 that the 3rd embodiment of the present invention obtains etc. the performance diagram of relation of the coherence factor of multiplying power projection optical system 26 and depth of focus.
Fig. 6 be illustrate the exposure device that utilizes Fig. 1 that the 4th embodiment of the present invention obtains etc. the performance diagram of relation of the numerical aperture of multiplying power projection optical system 26 and depth of focus.
Fig. 7 be illustrate the exposure device that utilizes Fig. 1 that the 5th embodiment of the present invention obtains etc. the performance diagram of relation of the coherence factor of multiplying power projection optical system 26 and depth of focus.
Fig. 8 is the planimetric map through the manufactured TFT of the exposure device that has used Fig. 1.
Fig. 9 is the sectional view that the 9-9 line along Fig. 8 obtains.
Figure 10 is the figure that an embodiment of the attenuated type mask that is used in the exposure process used of the explanation exposure method relevant with the present invention of explanation and the contact hole pattern that exposes-develop through light that utilizes this attenuated type mask uses, A is the planimetric map of attenuated type mask, and B is the sectional view that the processed substrate of using with the state that the mask pattern that obtains along the 10B-10B line among the A is exposed relatedly is described.
Figure 11 is the figure that an embodiment of the attenuated type mask that is used in the exposure process used of the explanation exposure method relevant with the present invention of explanation and the contact hole pattern that exposes-develop through light that utilizes this attenuated type mask uses, A is the planimetric map of attenuated type mask, and B is the sectional view that the processed substrate of using with the state that the mask pattern that obtains along the 11B-11B line among the A is exposed relatedly is described.
Figure 12 be illustrate the exposure device that utilizes Fig. 1 that the 6th embodiment of the present invention obtains etc. the performance diagram of relation of the numerical aperture of multiplying power projection optical system 26 and depth of focus.
Figure 13 be illustrate the exposure device that utilizes Fig. 1 that the 7th embodiment of the present invention obtains etc. the performance diagram of relation of the coherence factor of multiplying power projection optical system 26 and depth of focus.
Figure 14 be illustrate the exposure device that utilizes Fig. 1 that the 8th embodiment of the present invention obtains etc. the performance diagram of relation of the numerical aperture of multiplying power projection optical system 26 and depth of focus.
Figure 15 be illustrate the exposure device that utilizes Fig. 1 that the 9th embodiment of the present invention obtains etc. the performance diagram of relation of the coherence factor of multiplying power projection optical system 26 and depth of focus.
Figure 16 be when the light transmissive portion that changed the attenuated type mask that utilizes Figure 11 that the 10th embodiment of the present invention obtains equidistant is shown, with the performance diagram of the relation of depth of focus.
Figure 17 be illustrate the exposure device that utilizes Fig. 1 that the 11st embodiment of the present invention obtains etc. the performance diagram of relation of the numerical aperture of multiplying power projection optical system 26 and depth of focus.
Figure 18 be illustrate the exposure device that utilizes Fig. 1 that the 12nd embodiment of the present invention obtains etc. the performance diagram of relation of the coherence factor of multiplying power projection optical system 26 and depth of focus.
Embodiment
(definition of term)
In the present invention, so-called " rectangle " comprises Long Circle and ellipse.So-called contact hole is in order to be used for being electrically connected across insulation course between the conductor layer that is provided with on the surperficial back side, between electric conductor and source region or the drain region or the electric conductor between the gate electrode and in hole that above-mentioned insulation course is provided with so that wire is embedding.In this manual, also will be defined as contact hole utilizing etching to be processed to form the hole that is provided with in the photosensitive material sheet of using in this hole.
At first be described in the exposure device that method of manufacturing thin film transistor of the present invention and exposure method are used in the two, then narrate method of manufacturing thin film transistor of the present invention.
(embodiment of exposure device)
With reference to Fig. 1, exposure device 10 is made of following part except the light source 12 of exposure usefulness: catoptron 14, be configured on the light path from light source 12, and make the light reflection of penetrating from light source 12; 2 kinds of intermediate lenses 16 and 18 make the light pack of mirror 14 reflections that are reflected; Catoptron 20 makes the light from intermediate lens 18 reflect towards attenuated type mask 24; Condenser lens 22 makes the light pack of mirror 20 reflections that are reflected and shines attenuated type mask 24; And projection optical system 26, the light that will pass through attenuated type mask 24 for example shines on the photosensitive material layer that forms on the such processed substrate of glass substrate 28, for example resist film 30.
Projection optical system 26 be with the picture of mask 24 for example with etc. multiplying power project on the resist film 30 etc. the multiplying power projection optical system, in illustrated embodiment, possess NA diaphragm 32, pupil face 34 and a plurality of lens 36 etc.The light that has passed through attenuated type mask 24 through projection optical system 26 with etc. multiplying power incide on the resist film 30.
Resist film 30 for example is made of with the chemically amplified corrosion-resisitng agent material the i line.For example the photoresist material is coated on the surface of glass substrate 28, thereafter, makes its drying, form resist film 30 with the such suitable method of spin coated.
When the open angle with incident light is decided to be 2 φ, can from following formula (2) obtain as comprise condenser lens 22 lamp optical system 23 numerical aperture so that be the NA1 that incides the numerical aperture of the light on the attenuated type mask 24 from condenser lens 22.
NA1＝sinφ…(2)
Equally, when the open angle with incident light is decided to be 2 θ, can obtains as the numerical aperture of projection optical system 26 and then be the NA2 that incides the numerical aperture of the light on the resist film 30 from projection optical system 26 from following formula (3).
NA2＝sinθ...(3)
(embodiment of mask)
In the attenuated type mask 24 shown in Fig. 2 A and the B, if the sensitometric characteristic of resist film 30 is positivities, then zone 40 forms light transmissive region, and zone 42 forms the semipermeability light shaded areas with certain transmissivity.Different therewith, if the sensitometric characteristic of resist film 30 is negativity, then zone 40 forms the light shaded areas with certain transmissivity conversely, and zone 42 forms light transmissive region.
Can use as the chrome mask 124 with common shadow mask of contact hole pattern as described above to replace attenuated type mask 24, can be phase shift mask (attenuated type mask) 24 a certain of this chrome mask and attenuated type.
Be under the latter's the situation of attenuated type mask at attenuated type mask 24, can use by half light shaded areas with transmissivity of 6～8% and make the phase place Rotate 180 ° of light, simultaneously have roughly mask that the light transmissive region of 100% transmissivity constitutes or by have 6～8% transmissivity, simultaneously make light phase place Rotate 180 ° half light shaded areas and have roughly mask that the light transmissive region of 100% transmissivity constitutes as such mask 24.
The material of light shaded areas 42 usefulness is according to being the mask of above-mentioned any type and difference, but can use known material, for example MoSiO, MoSiON, the Cr that sells on the market.State in the use under the situation of any attenuated type mask 24, before the exposure of resist film 30, make mask 24 with such contact hole pattern.
(embodiment of TFT)
Fig. 8 and Fig. 9 illustrate the embodiment of the TFT52 that is made of the crystalline semiconductor that forms on the glass substrate of using at the such display panel of display panels 50.
With reference to Fig. 8 and Fig. 9, for example have the basalis 54 that has formed transparent electrical insulating property on the face of OBL glass substrate 50 in shape, on this basalis 54, formed the rectangular crystalline silicon layer 56 that each TFT element is separated into island.On silicon layer 56, source region S and drain region D on separated preposition, have been formed.Between source region S and drain region D, formed channel region C.Moreover, on this silicon layer 56, formed gate insulation layer 58.On gate insulation layer 58, formed the gate electrode layer.This gate electrode of mask pattern etching that uses gate electrode 60 forms gate electrode 60 thus with layer.On this gate electrode 60, gate insulation layer 58, basalis 54, form interlayer dielectric 66.On this interlayer dielectric 66, form resist film 30.To form glass substrate 28 location of resist film 30 and transport on the preposition of X-Y-Z-θ platform (not shown) of the exposure device 10 shown in Fig. 1.The light that sees through of the attenuated type mask 24 of the contact hole shown in Fig. 2 is incided on the resist film 30 and exposes.The resist film 30 that is exposed is carried out development treatment, on resist film 30, form the mask pattern of contact hole.The resist film 30 of mask pattern that formed this contact hole as mask, by carrying out the etching of the interlayer dielectric 66 shown in Fig. 9, is formed contact hole 68.Meanwhile, on the surface that becomes channel region of silicon layer 56, form gate insulation layer 58.
On gate insulation layer 58, form gate electrode 60, make it the central portion of the length direction of transversal silicon layer 56 on the Width of silicon layer 56 and extend.
By through predetermined foreign ion being injected in the silicon layer 56 that exposes in the bottom, in silicon layer 56, form source region S and drain region D at the contact hole 68 that forms on the interlayer dielectric 66.Secondly, form the material layer that is used for forming source electrode and drain electrode, formation source electrode 62 and drain electrode 64 in contact hole 68 thus on the silicon layer 56 that exposes the bottom by for example sputtering at.
Be mask with gate electrode 60, formed source electrode 62 and drain electrode 64 through contact hole 68 by under the states that are electrically connected respectively on implanting impurity ion forms in silicon layer 56 source region S and the drain region D.
In the part of manufacturing process, use among Fig. 8 and the TFT52 shown in Fig. 9 of the exposure device 10 shown in Fig. 1, perforation interlayer dielectric 66 has formed a plurality of contact holes 68 of source electrode 62 and drain electrode 64 usefulness, makes its bottom become the surface of above-mentioned source region S and drain region D.
On interlayer dielectric 66, form resist film 30, utilize 10 pairs of these resist films 30 of exposure device to expose, developing is formed on the contact hole 68 of formation on the interlayer dielectric 66.In this exposure process, use the attenuated type mask 24 shown in Fig. 2.Utilize this exposure process, be formed on the mask that forms contact hole 68 usefulness on the interlayer dielectric 66 on the resist film 30.By using this mask that interlayer dielectric 66 is carried out for example plasma etching of selective etching, on interlayer dielectric 66, form contact hole 68.If use in attenuated type mask 24 with the OBL pattern shown in Fig. 2 A exposure device 10 shown in Figure 1 resist film 30 is selected exposure and this resist film 30 is carried out development treatment, then as shown in Figure 8, formation is used for forming the mask that the bight is OBL contact hole 68 usefulness of arcuation on resist film 30.
The depth of focus of the situation of rectangular contact hole like this, as shown in Figure 3, along with long limit is elongated and deepen.Because depth of focus is dark, so be suitable for the resist that covers on the big glass substrate of thickness deviation is exposed.
By using this mask that interlayer dielectric 66 is selected exposure, on interlayer dielectric 66, form contact hole 68.By uniformly-spaced and equidistantly to arrange a plurality of contact holes, on resist film 30, form contact hole pattern.
[embodiment 1]
Shown in figure 2 in the attenuated type mask 24, rectangular regional 40 the minor face that for example becomes the light projector zone that will form contact hole 68 usefulness on resist film 30 for example is fixed as 0.5 μ m, make a plurality of attenuated type masks 24 on the long limit that has changed photopermeability zone 40, in order to use these attenuated type masks 24 on resist film 30, to form OBL contact hole, utilize 10 pairs of resist films 30 of the exposure device shown in Fig. 1 to expose.Except these attenuated type masks 24, also used the chrome mask that has a plurality of light-proofnesss of same shape with these attenuated type masks 24 respectively.
For example will wait the coherence factor σ (Sin φ/Sin α) of multiplying power projection optical system 26 to be fixed as 0.8.In addition, used wavelength as the i line of 365nm as the exposure light line, used the i line with the chemically amplified corrosion-resisitng agent material as resist film 30.Moreover, in the hole of the directions X in the zone 40 among Fig. 2 in the heart spacing XP be decided to be long limit and minor face (0.5 μ m) sum, in the hole of Y direction in the heart spacing YP be decided to be 4 times (2 μ m) of minor face (0.5 μ m).
Under the situation of having used chrome mask, the numerical aperture NA2 of the foursquare situation of the length that respectively has 0.5 μ m on one side in photopermeability zone 40 is decided to be 0.37,0.5 the numerical aperture NA2 of the rectangular situation of μ m * 0.7 μ m is decided to be 0.33,0.5 the numerical aperture NA2 of the rectangular situation of μ m * 1 μ m is decided to be the numerical aperture NA2 of the two rectangular situations of 0.29,0.5 μ m * 1.5 μ m and 0.5 μ m * 2 μ m and is decided to be 0.28.
Under the situation of having used the attenuated type mask, the numerical aperture NA2 of the foursquare situation of the length that respectively has 0.5 μ m on one side in photopermeability zone 40 is decided to be 0.35,0.5 the numerical aperture NA2 of the two rectangular situations of μ m * 0.7 μ m and 0.5 μ m * 1 μ m is decided to be the numerical aperture NA2 of the two rectangular situations of 0.25,0.5 μ m * 1.5 μ m and 0.5 μ m * 2 μ m and is decided to be 0.26.
The relation of the length dimension on the depth of focus of the projection optical system 26 that obtains as the result of the foregoing description 1 shown in Figure 3 and the long limit in the zone 40 in the attenuated type mask 24 shown in Fig. 2.In Fig. 3, have mark ◆ curve 70 expression used result's (depth of focus characteristic of the projection optical system 26 of exposure device 10) of the situation of chrome mask, result's (depth of focus characteristic of the projection optical system 26 of exposure device 10) of the situation of attenuated type mask 24 has been used in curve 72 expressions that have mark ■.The transverse axis of Fig. 3 is the length on the long limit in the zone 40 shown in Fig. 2, and the longitudinal axis is represented the depth of focus of the projection optical system 26 of exposure device 10.Obtained dark depth of focus characteristic during more than or equal to 0.7 μ m in the length on 40 long limit, zone.In other words, in the transverse axis of Fig. 3, the ratio of long limit and minor face is 1.4 times when being 0.7 μ m on long limit, is 2 times when being 1 μ m on long limit, is 3 times when being 1.5 μ m on long limit, is 4 times when being 2 μ m on long limit, is 5 times when being 2.5 μ m on long limit.Shown in figure 2 in the attenuated type mask 24, the length dimension that forms OBL pattern that contact hole uses and be long side direction has obtained dark depth of focus characteristic during more than or equal to the pattern of 1.4 times shape of the length dimension of short side direction.
Under the situation of having used any attenuated type mask 24, on resist film 30, form the contact hole that connects resist film 30 fully, these contact holes have and the corresponding oblong shape in rectangular light permeability zone (40) shown in Fig. 2 A.
As can understanding from Fig. 3, if 40 long limit, zone is longer than minor face (0.5 μ m), then in growing the scope of limit till the 1 μ m, the depth of focus of projection optical system 26 deepens, if it is longer than it to grow the limit, then depth of focus is roughly constant.Its result, in Fig. 3, by rectangularity is made in zone 40, the depth of focus of exposure device 10 deepens.
As can understanding from above-mentioned Fig. 3, if make 1.4 times (the 0.7 μ ms) of the length on 40 long limit, zone more than or equal to minor face 0.5 μ m, then compare for foursquare situation with the either party of light transmissive region with the light shaded areas, the depth of focus of projection optical system 26 deepens.At contact hole pattern is that the spacing of above-mentioned rectangular long side direction is can stably obtain dark depth of focus during more than or equal to 3 times of the length dimension of minor face periodic pattern for the spacing more than or equal to the length dimension sum of the size of the length on long limit and minor face and short side direction.Contact hole can be any zone of light transmissive region and light shaded areas.
The family curve 70 of Fig. 3 has been to use the characteristic of situation of the chrome mask in the zone 40 with photopermeability.As can be known in this case, by contact hole is made oblong-shaped, depth of focus also deepens.Thus, can understand the present invention also is effective to common Cr mask.
Under the situation of having used attenuated type mask 24, judge that depth of focus deepens significantly.Like this,, also can on resist film 30, connect and form the contact hole 28 that connects resist film 30 fully reliably, improve the yield rate that TFT makes even on the big glass substrate of the thickness deviation of the depth of focus that can obtain projection optical system 26.
[embodiment 2]
With the same shape of the attenuated type mask 24 shown in Fig. 2 in, the minor face that makes OBL light transmissive region or light shaded areas is fixed as 0.5 μ m, will grows the chrome mask that the limit is fixed as 1 μ m in addition, for a plurality of contact holes of using this chrome mask to form with arranged in high density on resist film 30 are intensive contact hole, utilize the numerical aperture NA2 of multiplying power projection optical systems 26 such as the exposure device 10 shown in Fig. 1 makes to change resist film 30 is exposed.
In this embodiment, also coherence factor σ is fixed as 0.8.In addition, used wavelength as the i line of 365nm as the exposure light line, used the i line with the chemically amplified corrosion-resisitng agent material as resist film 30.Moreover, in the hole of the directions X in the zone 40 among Fig. 2 in the heart spacing XP be decided to be 1.5 μ m, in the hole of Y direction in the heart spacing YP be decided to be 2 μ m.
Result as the foregoing description 2 shown in Figure 4 obtain etc. multiplying power projection optical system 26 depth of focus with etc. the relation of numerical aperture NA2 of multiplying power projection optical system 26.Form the contact hole 68 that connects resist film 30 fully on resist film 30, these contact holes 68 have rectangular shape as shown in Fig. 2 A.
As can understanding from Fig. 4, be 0.29 o'clock at the numerical aperture NA2 that waits multiplying power projection optical system 26, depth of focus is the darkest.At numerical aperture NA2 is 0.287 to 0.315 o'clock, has obtained dark depth of focus.In addition, if according to Fig. 3, light transmissive region or light shaded areas 40 are rectangles, then compare with foursquare zone, and depth of focus is integrally dark more than or equal to ± 1.7 μ m.
In Fig. 4 about embodiment 2, be 0.28 o'clock and 0.3 o'clock at the numerical aperture NA2 that waits multiplying power projection optical system 26, become roughly the same depth of focus.But, if consider lens aberration, then since etc. the numerical aperture NA2 of multiplying power projection optical system 26 be that 0.28 o'clock depth of focus is more shallow, so the scope of numerical aperture NA2 is 0.29～0.315th, best.
Obtain the scope 0.40～0.43 of the k1 corresponding with it from the scope of the numerical aperture NA2 of multiplying power projection optical system 26 such as described above.As following, obtain the scope of this k1.
In above-mentioned formula (1), if supposition R is 0.5, numerical aperture NA2 is 0.29, then k1 is 0.40.Equally, if supposition R is 0.5, numerical aperture NA2 is 0.315, then k1 is 0.43.
[embodiment 3]
Be fixed as 0.5 μ m, will grow the chrome mask that the limit is fixed as 1 μ m in addition with the minor face that has made rectangular light transmissive region or light shaded areas with the same shape of the attenuated type mask 24 shown in Fig. 2.In order to use the chrome mask that has been made on resist film 30, to form intensive contact hole, utilize the coherence factor σ variation of multiplying power projection optical systems 26 such as the exposure device 10 shown in Fig. 1 makes that resist film 30 is exposed.
At this moment, with etc. the numerical aperture NA2 of multiplying power projection optical system 26 be fixed as 0.29.In addition, used wavelength as the i line of 365nm as the exposure light line, used the i line with chemically amplified corrosion-resisitng agent as resist film 30.Moreover, the directions X spacing XP of light transmissive region among Fig. 2 or light shaded areas 40 is decided to be 1.5 μ m, YP is decided to be 2 μ m with Y direction spacing.
Result as the foregoing description 3 shown in Figure 5 obtain etc. multiplying power projection optical system 26 depth of focus with etc. the relation of coherence factor σ of multiplying power projection optical system 26.Under any situation, all on resist film 30, form the hole (contact hole) that connects resist film 30 fully, these contact holes have and the corresponding oblong shape of rectangle (40) shown in Fig. 2 A.
As can understanding from Fig. 5, be 0.5 o'clock at coherence factor σ, demonstrating depth of focus is minimum trend.In Fig. 5, at coherence factor σ more than or equal to 0.5 with demonstrated depth of focus smaller or equal to 0.5 o'clock and deepen.
In addition, light transmissive region or light shaded areas 40 compared for foursquare situation for rectangular situation and light transmissive region or light shaded areas 40, and depth of focus deepens in Zone Full, can understand to there is no need to limit coherence factor σ in chrome mask.
[embodiment 4]
Shown in figure 2 in the attenuated type mask 24, the minor face that makes OBL light transmissive region or light shaded areas is fixed as 0.5 μ m, will grows the attenuated type mask that the limit is fixed as 1 μ m in addition, in order to use this attenuated type mask on resist film 30, to form intensive contact hole, utilize the numerical aperture NA2 variation of multiplying power projection optical systems 26 such as the exposure device 10 shown in Fig. 1 makes that resist film 30 is exposed.
σ is fixed as 0.8 with coherence factor.In addition, used wavelength as the i line of 365nm as the exposure light line, used the i line with the chemically amplified corrosion-resisitng agent material as resist film 30.Moreover, the directions X spacing XP of light transmissive region among Fig. 2 or light shaded areas 40 is decided to be 1.5 μ m, YP is decided to be 2 μ m with Y direction spacing.
Result as the foregoing description 4 shown in Figure 6 obtain etc. the depth of focus of multiplying power projection optical system 26 and the relation of numerical aperture NA2.Under any situation, all on resist film 30, form hole, for example contact hole that connects resist film 30 fully, these contact holes have and the corresponding rectangular shape of rectangle masks area (40) shown in Fig. 2 A.
As can understanding from Fig. 6, be at 0.25 o'clock at the numerical aperture NA2 that waits multiplying power projection optical system 26, the darkest etc. the depth of focus of multiplying power projection optical system 26.At the numerical aperture NA2 that waits multiplying power projection optical system 26 is 0.24 and 0.265 o'clock, becomes roughly the same depth of focus.If but consider lens aberration, then since etc. the numerical aperture NA2 of multiplying power projection optical system 26 be that 0.24 o'clock depth of focus is more shallow, so the scope of numerical aperture NA2 is decided to be 0.25～0.265th, desirable.
Fig. 4 illustrates the characteristic about common chrome mask, and Fig. 6 illustrates the characteristic about the attenuated type mask.If comparison diagram 4 and Fig. 6, then the depth of focus of the situation of attenuated type mask is darker, under the situation about forming of on the glass substrate TFT being exposed, is very effective.
[embodiment 5]
Shown in figure 2 in the attenuated type mask 24, make rectangular regional 40 minor face is fixed as 0.5 μ m, will grows the attenuated type mask that the limit is fixed as 1 μ m in addition, in order to use this attenuated type mask on resist film 30, to form intensive contact hole, utilize the exposure device 10 shown in Fig. 1 that coherence factor σ is changed resist film 30 is exposed.
NA2 is fixed as 0.25 with numerical aperture.In addition, used wavelength as the i line of 365nm as the exposure light line, used the i line with chemically amplified corrosion-resisitng agent as resist film 30.Moreover, the directions X spacing XP in the zone among Fig. 2 40 is decided to be 1.5 μ m, YP is decided to be 2 μ m with Y direction spacing.
Result as the foregoing description 5 shown in Figure 7 obtain etc. the depth of focus of multiplying power projection optical system 26 and the relation of coherence factor σ.Under any situation, all on resist film 30, form the hole (contact hole) that connects resist film 30 fully, these contact holes have and the corresponding oblong shape of rectangle (40) shown in Fig. 2 A.
Fig. 5 illustrates the characteristic about common chrome mask, and Fig. 7 illustrates the characteristic about the attenuated type mask.If comparison diagram 5 and Fig. 7, then the depth of focus of the situation of attenuated type mask is darker, under the situation about forming of on the glass substrate TFT being exposed, is very effective.
Coherence factor σ more than or equal to 0.3 situation under, zone 40 is compared for the situation of square (shape in the mask) with zone 40 for rectangular situation, since etc. the depth of focus of multiplying power projection optical system 26 deepened, so can understand and under the situation of attenuated type mask 24, there is no need to limit coherence factor σ.At this, zone 40 is the situation of 0.5 μ m for the long limit that foursquare situation is equivalent to Fig. 3.The coherence factor σ that has compared the depth of focus 1.2 μ m of this moment and Fig. 7 is more than or equal to 0.3 depth of focus.
Under situation as described above,, also can obtain 0.5 μ m as set resolution even make numerical aperture NA2 change to 0.3.Can obtain the scope of corresponding k1 from the scope 0.25～0.3 of such numerical aperture NA2.That is, in above-mentioned formula (1), when the length dimension that R is decided to be above-mentioned rectangular short side direction (0.5 μ m), in the above-mentioned formula of each critical value substitution (1), obtain the scope 0.34～0.41 of k1 with the scope 0.25～0.3 of numerical aperture NA2.
Can understand that from the foregoing description 2 to 5 if identical resolution, then zone 40 is compared for foursquare situation with regional 40 for rectangular situation, available little numerical aperture NA2 exposes.If numerical aperture NA2 reduces in this wise, then the making difficulty of lens has reduced.
Moreover, in above-mentioned example, the contact hole 68 of electrode 62,64 usefulness of the source that forms thin film transistor (TFT) 52 and drain region SD has been described, but has been not limited to these contact holes 68, also can in the formation of the contact hole 68 of the wiring usefulness of gate electrode 60, implement.Moreover, in order on interlayer dielectric 66, to be formed on the contact hole that is provided with in the wiring that connects between 52 of thin film transistor (TFT)s or power supply terminal etc., can similarly form, can obtain same effect, this point need not to have illustrated.
In above-mentioned example, illustrated that the shape that will form the mask pattern that contact hole uses forms OBL example, even but the mask pattern of elliptical shape, also can similarly obtain can be practical etc. the depth of focus of multiplying power projection optical system 26.
Secondly, narration exposure method.
About the attenuated type mask 124 that in exposure, is used, for example as shown in Figure 10 A, can make have with equidistantly formed light transmissive portion 140 with identical width dimensions and light shielding portion 142 uniformly-spaced with the lines of equally spaced lines-gap pattern phase shift mask with attenuated type.Figure 10 is the figure that explanation attenuated type mask 124 and the embodiment that sees through the resist pattern that light exposes-develop that utilizes this attenuated type mask 124 use, A is the planimetric map of attenuated type mask 124, and B is the sectional view that the processed substrate of using with the state that the mask pattern that obtains along the 10B-10B line among the A is exposed relatedly is described.
About attenuated type mask 124, for example as shown in Figure 11 A, also can make have with equidistantly with rectangular formed light transmissive portion 144 with identical width dimensions uniformly-spaced with the contact hole of equally spaced intensive contact hole pattern phase shift mask with attenuated type.In these illustrated embodiment, also the width dimensions with light transmissive portion 144 is identical for the size of (that is, the light shielding portion 146) between the light transmissive portion 144.Figure 11 is the figure that explanation attenuated type mask 124 and the embodiment that sees through the resist pattern that light exposes-develop that utilizes this attenuated type mask 124 use, A is the planimetric map of attenuated type mask 124, and B is the sectional view that the processed substrate of using with the state that the mask pattern that obtains along the 11B-11B line among the A is exposed relatedly is described.
Even attenuated type mask 124 has above-mentioned any pattern; as attenuated type mask 124, can use by the light shielding portion 142,146 with transmissivity of 6～8% and make the phase place Rotate 180 ° of light, simultaneously have roughly mask that the light transmissive portion 140,144 of 100% transmissivity constitutes or by have 6～8% transmissivity, simultaneously make light phase place Rotate 180 ° the light shielding portion and have roughly any of mask that the light transmissive portion of 100% transmissivity constitutes.
The material of light shielding portion 142 and 146 usefulness is according to being the mask of above-mentioned any type and different, but can use the known material of selling on the market.State in the use under the situation of any attenuated type mask 124, before the exposure of resist layer 130, make attenuated type mask 124 with such pattern.
If use 124 pairs of resist layers 130 of attenuated type mask to expose in the exposure device shown in Figure 1 10 with the pattern shown in Figure 10 A, after exposure, resist layer 130 is carried out development treatment, then on the resist layer 130 of glass substrate 128, form among Figure 10 B with shown in the sectional view such uniformly-spaced, the part of the remaining resist layer 130 of equally spaced usefulness and removed this resist layer part, be lines-gap pattern that space 150 constitutes.
In the pattern shown in Figure 10 B, the light transmissive portion 140 of the pattern among the space 150 of having removed resist layer 130 and Figure 10 A is corresponding, and the light shielding portion 142 of the pattern among the remaining part 152 of resist layer 130 and Figure 10 A is corresponding.
If in exposure device 10, use 124 pairs of resist layers 130 of attenuated type mask to expose with the pattern shown in Figure 11 A, after exposure, resist layer 130 is carried out development treatment, then on the resist layer 130 of glass substrate 128, form among Figure 11 B with shown in the sectional view such uniformly-spaced, equally spaced intensive contact hole pattern.
In the exposing patterns shown in Figure 11 B, the light transmissive portion 144 of the pattern among the space 150 of having removed resist layer 130 and Figure 11 A is corresponding, and the light shielding portion 146 of the pattern among the remaining part 156 of resist layer 130 and Figure 11 A is corresponding.
For example, in above-mentioned 1st exposure method relevant with the present invention, be used for from the i of exposure light source line (wavelength: 365nm) plan to form under the situation of photoresist (i line chemically amplified corrosion-resisitng agent) layer 130 with the lines-gap pattern that constitutes by the line that uniformly-spaced is configured with 0.5 μ m width, numerical aperture NA2 become with shown in the oblong-shaped dotted box of Figure 12 etc. dark area 0 .3～0.32 of depth of focus of multiplying power projection optical system 26, coherence factor σ become with shown in the oblong-shaped dotted box of Figure 13 etc. dark regional about 0.75～0.85 (also identical under the situation of common Cr mask) of depth of focus of multiplying power projection optical system 26.Coherence factor σ is dark depth of focus more than or equal to 0.85, but it is very difficult to make actual exposure optical system with such σ.Thereby, coherence factor σ is decided to be about 0.75～0.85.In addition, in above-mentioned formula (1) during R=0.5 μ m, in the above-mentioned formulas of two critical value substitutions (1), obtain the scope 0.41～0.44 of k1 with the scope 0.3～0.32 of numerical aperture NA2.
In addition, for example be used for from the i of exposure light source line (wavelength: 365nm) plan to form i line and use under the situation of chemically amplified corrosion-resisitng agent with the lines-gap pattern that constitutes by the line that uniformly-spaced is configured with 0.8 μ m width, characteristic according to the oblong-shaped dotted box of Figure 12, numerical aperture NA2 becomes 0.18～0.2, according to the characteristic of the oblong-shaped dotted box of Figure 13, coherence factor σ is about 0.75～0.85.
For example in above-mentioned 2nd exposure method relevant with the present invention, be used for from the i of exposure light source line (wavelength: 365nm) go up contact hole (the intensive contact hole that formation constitutes uniformly-spaced to dispose the hole of the bore with 0.5 μ m at resist (i line chemically amplified corrosion-resisitng agent), in the hole in the heart spacing be 1 μ m) the seeing through under the situation of light image of the mask 124 of pattern, according to Figure 17, numerical aperture NA2 etc. multiplying power projection optical system 26 becomes 0.35～0.365, according to Figure 15, be about 0.6～0.85 (also identical under the situation of common Cr mask) etc. the coherence factor σ of multiplying power projection optical system 26.In addition, in above-mentioned formula (1) during R=0.5 μ m, in the above-mentioned formulas of two critical value substitutions (1), obtain the scope 0.48～0.5 of k1 with the scope 0.35～0.365 of numerical aperture NA2.
In addition, for example (wavelength: 365nm) the attenuated type mask 124 that go up to form the intensive contact hole pattern that a plurality of holes by the bore with 0.8 μ m constitute (in the hole spacing be 1.6 μ m) in the heart at resist film 130 (i line chemically amplified corrosion-resisitng agent) sees through under the situation of light image from the i of exposure light source line being used for, numerical aperture NA2 etc. multiplying power projection optical system 26 becomes 0.22～0.23, is about 0.6～0.85 (also identical under the situation of common Cr mask) etc. the coherence factor σ of multiplying power projection optical system 26.The hole shape of attenuated type mask 124 is a square, but the shape of the resist pattern that in fact forms becomes circle.
For example in above-mentioned the 3rd exposure method, have in formation under the situation in hole of bore of 0.5 μ m, in the hole of attenuated type mask 124 in the heart spacing be more than or equal to 1.2 μ m.In addition, become 0.35～0.365, be about 0.3～0.55 etc. the coherence factor σ of multiplying power projection optical system 26 etc. the numerical aperture NA2 of multiplying power projection optical system 26.In this case, in above-mentioned formula (1) during R=0.5 μ m, in the above-mentioned formulas of two critical value substitutions (1), obtain the scope 0.48～0.5 of k1 with the scope 0.35～0.365 of numerical aperture NA2.
According to such use the exposure method of attenuated type mask 124, compare with the situation of common Cr mask, deepen etc. the depth of focus of multiplying power projection optical system 26.If depth of focus deepens, then can form pattern with high precision on by the resist film 130 of film forming on the big glass substrate of thickness deviation.Carrying out the imaging this point to the meticulous pattern of height on by the resist film 130 of film forming on the big glass substrate of thickness deviation, mean the high density integrated circuit that on glass substrate, can form TFT.
In addition, in exposure method of the present invention as described above, if with the identical resolution of situation of common Cr mask, then compare with the situation of common Cr mask, available little numerical aperture NA2 exposes.If numerical aperture NA2 reduces in this wise, then the making difficulty of lens has reduced (it is easy that the making of lens becomes).
[embodiment 6]
For on resist layer 130, be formed on live width in lines-gap pattern be in 0.5 μ m and the line in the heart spacing be 1 μ m uniformly-spaced, equally spaced lines-gap pattern, use the mask shown in Figure 10 A as attenuated type mask 124, utilize the exposure device 10 shown in Fig. 1, resist layer 130 is exposed.
Used wavelength as the i line of 365nm as exposure light, used the i line with the chemically amplified corrosion-resisitng agent material as resist layer 130.
In practice, σ is fixed as 0.8 with coherence factor, carried out among change and Fig. 1 etc. a plurality of experiments of angle of convergence θ value corresponding aperture NA2 of multiplying power projection optical system 26.
The exposure device 10 that obtains as the result of the foregoing description 6 shown in Figure 12 etc. the relation of numerical aperture NA2 of the depth of focus of multiplying power projection optical system 26 and projection optical system 26.
As can understanding from Figure 12, be at 0.3 o'clock at the numerical aperture NA2 that waits multiplying power projection optical system 26, the darkest etc. the depth of focus of multiplying power projection optical system 26.At numerical aperture NA2 is that 0.29 o'clock and numerical aperture NA2 are 0.32 o'clock, becomes roughly the same depth of focus.
But, if consideration lens aberration, then since etc. the numerical aperture NA2 of multiplying power projection optical system 26 be that 0.29 o'clock depth of focus is more shallow, so the scope of numerical aperture NA2 is decided to be in Figure 12 with 0.3～0.32nd shown in the dotted box, desirable, this point is understood.The scope of such numerical aperture is compared with common Cr mask, demonstrates good characteristic.
At this moment, R=0.5 μ m, λ=365nm, if be called as the scope of obtaining k1 in the formula (1) of Rayleigh formula by scope 0.3～0.32 substitution with numerical aperture NA2, the scope of then obtaining 0.410.44 is as k1.
[embodiment 7]
For on resist layer 130, form identical with embodiment 6 uniformly-spaced, equally spaced line lines-gap pattern, use the attenuated type mask 124 shown in Figure 10 A as attenuated type mask 24, utilize the exposure device 10 shown in Fig. 1, under the condition identical, resist layer 130 is exposed with embodiment 6.
Be to have carried out numerical aperture NA2 is fixed as 0.3, changes coherence factor σ and replace coherence factor σ is fixed as 0.8, changes a plurality of experiments of numerical aperture NA2 with the difference of embodiment 6.
The exposure device 10 that obtains as the result of the foregoing description 7 shown in Figure 13 etc. the depth of focus of multiplying power projection optical system 26 and the relation of coherence factor σ.
As can understanding from Figure 13, coherence factor σ than 0.8 little zone in, diminish etc. the depth of focus of multiplying power projection optical system 26, if be lower than 0.75, then depth of focus is lower than ± 2 μ m significantly.But if coherence factor σ is bigger than 0.8, then depth of focus is roughly constant.
Manufacturing limit about the light source of coherence factor σ is roughly more than or equal to 0.85.Thereby coherence factor σ is decided to be among Figure 13 with 0.75～0.85th shown in the dotted box, and desirable, this point is understood.
[embodiment 8]
For on resist layer 130, be formed on have in the resist pattern on one side be 0.5 μ m a plurality of rectangular openings, be bore be in a plurality of holes of 0.5 μ m and the hole in the heart spacing be the intensive contact hole pattern of 1 μ m, use the mask shown in Figure 11 A as attenuated type mask 124, utilize the exposure device 10 shown in Fig. 1, resist layer 130 is exposed.
Used wavelength as the i line of 365nm as exposure light, used the i line with the chemically amplified corrosion-resisitng agent material as resist layer 130.
In practice, σ is fixed as 0.8 with coherence factor, has carried out changing a plurality of experiments of numerical aperture NA2.
The exposure device 10 that obtains as the result of the foregoing description 8 shown in Figure 14 etc. the relation of numerical aperture NA2 of the depth of focus of multiplying power projection optical system 26 and projection optical system 26.
As can understanding from Figure 14, the numerical aperture NA2 of the projection optical system 26 in exposure device 10 is 0.35 o'clock, and the depth of focus of projection optical system 26 is the darkest.At the numerical aperture NA2 of projection optical system 26 is that 0.34 o'clock and numerical aperture NA2 are 0.365 o'clock, becomes roughly the same depth of focus.
But, if consider lens aberration, then since numerical aperture NA2 to be 0.34 o'clock the depth of focus of projection optical system 26 more shallow, so the scope of numerical aperture NA2 is decided to be in Figure 14 with 0.35～0.365th shown in the dotted box, desirable, this point is understood.
The R=0.5 μ m of this moment, λ=365nm, if be called as the scope of obtaining k1 in the formula (1) of Rayleigh formula by scope 0.35～0.365 substitution with numerical aperture NA2,0.48～0.5 the scope then obtained is as k1.
[embodiment 9]
In order on resist layer 130, to form the intensive resist pattern identical with embodiment 8, under the condition identical, utilize and adopted the mask shown in Figure 11 A to expose as the exposure device 10 shown in Fig. 1 of attenuated type mask 124 with embodiment 8.
Be to have carried out numerical aperture NA2 is fixed as 0.35, changes coherence factor σ and replace coherence factor σ is fixed as 0.8, changes a plurality of experiments of numerical aperture NA2 with the difference of embodiment 8.
The analog result of the relation of the depth of focus of the projection optical system 26 of the exposure device 10 that in the foregoing description 9, numerical aperture NA2 is fixed as 0.35 situation shown in Figure 15 and the coherence factor σ of projection optical system 26.
As can understanding from Figure 15, coherence factor σ than 0.8 little zone in, diminish etc. the depth of focus of multiplying power projection optical system 26, if be lower than 0.60, then depth of focus is lower than ± 1.2 μ m significantly.But if coherence factor σ is bigger than 0.8, then depth of focus is roughly constant.
Manufacturing limit about the light source of coherence factor σ is roughly 0.85 as mentioned above.Thereby coherence factor σ is decided to be among Figure 15 with 0.6～0.85th shown in the dotted box, and desirable, this point is understood.
[embodiment 10]
To have in the resist pattern on one side be the attenuated type mask 124 of the intensive contact hole pattern of a plurality of rectangular openings of 0.5 μ m in order to be formed on resist layer 130, use the mask 124 shown in Figure 11 A as attenuated type mask 124, utilize the exposure device 10 shown in Fig. 1, resist layer 130 is exposed.
Used wavelength as the i line of 365nm as exposure light, used the i line with the chemically amplified corrosion-resisitng agent material as resist layer 130.
In practice, the numerical aperture NA2 of exposure device 10 is fixed as 0.35, has carried out changing a plurality of experiments of the distance between centers (in spacing) in the heart in coherence factor σ and hole.When spacing was 1 μ m in the heart in the hole, σ was decided to be 0.8 with coherence factor, and in addition the time, σ is decided to be 0.4 with coherence factor.
The relation of the depth of focus of spacing and projection optical system 26 in the heart in the hole of the attenuated type mask 124 that obtains as the result of the foregoing description 10 shown in Figure 16.
As can understanding from Figure 16, if have the identical hole width size of attenuated type mask 124 is the equidistant 1 μ m of surpassing of the light transmissive portion 144 of bore, then the depth of focus of projection optical system 26 deepens sharp, in the heart under the situation of spacing more than or equal to 2 μ m, depth of focus is roughly constant in the hole.Spacing be decided to be depth of focus more than or equal to ± 2 μ m be desirable more than or equal to 1.2 μ m, this point is understood.In Figure 16, so-called " isolating " is the situation that has contact hole singlely.
[embodiment 11]
For on resist layer 130, be formed on have in the resist pattern on one side be 0.5 μ m a plurality of rectangular openings, its separately in the heart spacing be configured to the intensive contact hole pattern of the rectangular opening of 2 μ m, use the mask shown in Fig. 3 A as attenuated type mask 124, utilize the exposure device 10 shown in Fig. 1, resist layer 130 is exposed.
Used wavelength as the i line of 365nm as exposure light, used the i line with the chemically amplified corrosion-resisitng agent material as resist layer 130.
In practice, σ is fixed as 0.4 with coherence factor, has carried out changing a plurality of experiments of numerical aperture NA2.
Result as the foregoing description 11 shown in Figure 17 has obtained in the hole relation of the depth of focus of spacing and projection optical system 26 in the heart.
As can understanding from Figure 17, be 0.35 o'clock at numerical aperture NA2, the depth of focus of projection optical system 26 is the darkest.Showing at numerical aperture NA2 with dotted box in Figure 17 is that 0.34 o'clock and numerical aperture NA2 became the zone of roughly the same depth of focus at 0.365 o'clock.
But, if consider lens aberration in practice, then since numerical aperture NA2 to be 0.34 o'clock the depth of focus of projection optical system 26 more shallow, so the scope of numerical aperture NA2 is decided to be 0.35～0.365th, comparatively desirable, this point is understood.The scope of the k1 of this moment be same in the scope shown in the embodiment 8, be 0.48～0.5.
[embodiment 12]
In order will to be that a plurality of rectangular openings of 0.5 μ m are configured to wherein in the heart that spacing is the intensive contact hole pattern of 2 μ m on one side in the resist pattern forming on the resist layer 130, use the mask shown in Figure 11 A as attenuated type mask 124, utilize the exposure device 10 shown in Fig. 1, resist layer 130 is exposed.
Used wavelength as the i line of 365nm as exposure light, used the i line with the chemically amplified corrosion-resisitng agent material as resist layer 130.
In practice, NA2 is fixed as 0.35 with numerical aperture, has carried out changing a plurality of experiments of coherence factor σ.
Result as the foregoing description 12 shown in Figure 18 has obtained the relation of the depth of focus of coherence factor σ and projection optical system 26.
As can understanding from Figure 18, be 0.4 o'clock at coherence factor σ, demonstrate depth of focus and be very big such trend.In addition, coherence factor σ is decided to be depth of focus more than or equal to 0.3～0.55th of ± 2 μ m, and desirable, this point is understood.
In above-mentioned exposure method of the present invention, for example in the manufacturing of LCD, used under the situation of the line image mask relevant with the present invention, on LCD, form fabrication portion with the roughly corresponding size and dimension of the line image of this mask pattern.In addition, utilize each exposure device to determine value and the light source of numerical aperture NA2.
The present invention is not limited to the foregoing description, only otherwise break away from its main idea, can do various changes.
Claims (20)
1. method of manufacturing thin film transistor is characterized in that:
Be included in through mask and will by above-mentioned photosensitive material sheet is developed, on above-mentioned photosensitive material sheet, form the operation of contact hole from the irradiate light of light source to after on the photosensitive material sheet that is provided with on the glass substrate,
Above-mentioned light is the i line,
Being used to of aforementioned mask, the expose mask pattern of contact hole was the contact hole pattern that comprises a certain side of OBL light transmissive region and light shaded areas,
The shape of above-mentioned OBL pattern is that the length dimension of long side direction of this pattern is more than or equal to 1.4 times of the length dimension of short side direction.
2. the method for manufacturing thin film transistor described in claim 1 is characterized in that:
The contact hole that forms on above-mentioned photosensitive material sheet has the rectangular flat shape that makes each bight become arcuation at least.
3. method of manufacturing thin film transistor, comprise on the photosensitive material sheet that irradiate light that mask will incide on the optical system and will pass through above-mentioned optical system from the light of light source is provided with to the surface at glass substrate with the operation of this photosensitive material sheet that exposes, it is characterized in that:
Above-mentioned light is the i line,
Aforementioned mask is the chrome mask of light-proofness, and mask pattern contact hole, that formed by above-mentioned chrome mask that is used to form the thin film transistor (TFT) that forms on above-mentioned glass substrate is a certain side of OBL light transmissive region and light shaded areas,
Multiplying power projection optical systems such as above-mentioned optical system is when k1 being decided to be coefficient with value of 0.40 to 0.43 and R is decided to be the length dimension of above-mentioned rectangular short side direction, have the numerical aperture NA that utilizes following formula to obtain:
NA2＝k1×0.365/R。
4. method of manufacturing thin film transistor, comprise the irradiate light that will incide on the optical system and will pass through above-mentioned optical system from the light of light source through mask on the photosensitive material sheet that is provided with on the glass substrate with the operation of this photosensitive material sheet that exposes, it is characterized in that:
Above-mentioned light is the i line,
Aforementioned mask is the attenuated type mask, a certain side that mask pattern contact hole, above-mentioned attenuated type mask that is used to form the thin film transistor (TFT) that forms on above-mentioned glass substrate is OBL light transmissive region and light shaded areas,
Multiplying power projection optical systems such as above-mentioned optical system is when k1 being decided to be coefficient with value of 0.34 to 0.41 and R is decided to be the length dimension of above-mentioned rectangular short side direction, have the numerical aperture NA that utilizes following formula to obtain:
NA2＝k1×0.365/R。
5. the method for manufacturing thin film transistor described in claim 1 is characterized in that:
The aforementioned mask pattern that is used to form above-mentioned contact hole disposes a certain side of above-mentioned light transmissive region and light shaded areas more than or equal to the spacing of the length dimension sum of the length dimension on long limit and minor face and short side direction more than or equal to 3 times periodic patterns of the length dimension of minor face with the spacing of above-mentioned rectangular long side direction and constitutes.
6. the method for manufacturing thin film transistor described in claim 3 is characterized in that:
The aforementioned mask pattern that is used to form above-mentioned contact hole disposes a certain side of above-mentioned light transmissive region and light shaded areas more than or equal to the spacing of the length dimension sum of the length dimension on long limit and minor face and short side direction more than or equal to 3 times periodic patterns of the length dimension of minor face with the spacing of above-mentioned rectangular long side direction and constitutes.
7. the method for manufacturing thin film transistor described in claim 4 is characterized in that:
The aforementioned mask pattern that is used to form above-mentioned contact hole disposes a certain side of above-mentioned light transmissive region and light shaded areas more than or equal to the spacing of the length dimension sum of the length dimension on long limit and minor face and short side direction more than or equal to 3 times periodic patterns of the length dimension of minor face with the spacing of above-mentioned rectangular long side direction and constitutes.
8. the method for manufacturing thin film transistor described in claim 1 is characterized in that:
Utilize being developed in after the exposure of above-mentioned photosensitive material sheet to have the rectangular flat shape that makes each bight become arcuation at least by the contact hole that forms accordingly with the aforementioned mask pattern on the film formed resist film of this photosensitive material.
9. the method for manufacturing thin film transistor described in claim 3 is characterized in that:
Utilize being developed in after the exposure of above-mentioned photosensitive material sheet to have the rectangular flat shape that makes each bight become arcuation at least by the contact hole that forms accordingly with the aforementioned mask pattern on the film formed resist film of this photosensitive material.
10. the method for manufacturing thin film transistor described in claim 4 is characterized in that:
Utilize being developed in after the exposure of above-mentioned photosensitive material sheet to have the rectangular flat shape that makes each bight become arcuation at least by the contact hole that forms accordingly with the aforementioned mask pattern on the film formed resist film of this photosensitive material.
11. a thin film transistor (TFT) comprises: source region that is provided with on the semiconductive thin film of the crystallization on the glass substrate and drain region; At the gate insulating film that between above-mentioned source region and drain region, is provided with on the above-mentioned semiconductive thin film; The gate electrode that on this gate insulating film, is provided with; The 2nd dielectric film that on above-mentioned gate electrode, above-mentioned source region and drain region, is provided with; And in the 2nd dielectric film, be provided with, be provided with and be used for obtaining the contact hole of the conductor layer that electrically contacts with at least one of above-mentioned gate electrode, above-mentioned source region and drain region, it is characterized in that:
The section shape of above-mentioned contact hole is an oblong-shaped, and the length dimension of the long side direction of the section shape of this contact hole is more than or equal to 1.4 times of the length dimension of its short side direction.
12. an integrated circuit that is included in the thin film transistor (TFT) that is provided with on the semiconductive thin film of the crystallization on the glass substrate is characterized in that:
The section shape of the contact hole of this integrated circuit is an oblong-shaped, and the length dimension of the long side direction of the section shape of this contact hole is more than or equal to 1.4 times of the length dimension of its short side direction.
13. a liquid crystal indicator that comprises the thin film transistor (TFT) that constitutes driving circuit, above-mentioned driving circuit are used for the liquid crystal display that is provided with on the semiconductive thin film of the crystallization on the glass substrate, it is characterized in that:
The section shape of the contact hole of this driving circuit is an oblong-shaped, and the length dimension of the long side direction of the section shape of this contact hole is more than or equal to 1.4 times of the length dimension of its short side direction.
14. the contact hole for the circuit that is provided with on the semiconductive thin film that is formed on the crystallization on the glass substrate, the method for the photosensitive material sheet that forms on above-mentioned semiconductor film through the exposure of mask selectivity is characterized in that:
The pattern of aforementioned mask is an oblong-shaped, and the length dimension of this OBL long side direction is more than or equal to 1.4 times of the length dimension of its short side direction.
15. exposure method that has used the phase shift mask of attenuated type, wherein, to incide the above-mentioned irradiate light that also will pass through above-mentioned optical system on the optical system from the light of exposure light source through the attenuated type mask and to the resist layer that constitutes by the photosensitive material on the glass substrate, expose, it is characterized in that:
Above-mentioned light is the i line,
Above-mentioned attenuated type mask has line image,
Multiplying power projection optical systems such as above-mentioned optical system is when k1 being decided to be the coefficient with value of 0.41 to 0.44 and R being decided to be the width of the lines that form on the above-mentioned resist layer, have the numerical aperture NA that utilizes following formula to obtain:
NA2＝k1×0.365/R。
16. the use described in claim 15 exposure method of phase shift mask of attenuated type, it is characterized in that:
The coherence factor σ of above-mentioned i line is 0.75 to 0.85.
17. exposure method that uses the attenuated type mask, wherein, to incide the above-mentioned irradiate light that also will pass through above-mentioned optical system on the optical system from the light of exposure light source through the attenuated type mask and to the resist layer that constitutes by the photosensitive material on the glass substrate, expose, it is characterized in that:
Above-mentioned light is the i line,
Above-mentioned attenuated type mask has contact hole pattern,
Multiplying power projection optical systems such as above-mentioned optical system is when k1 being decided to be the coefficient with value of 0.48 to 0.5 and R being decided to be the diameter in the hole that forms on the above-mentioned resist layer, have the numerical aperture NA that utilizes following formula to obtain:
NA2＝k1×0.365/R。
18. the use described in claim 17 exposure method of phase shift mask of attenuated type, it is characterized in that:
The coherence factor σ of above-mentioned i line is 0.6 to 0.8.
19. exposure method that uses the attenuated type mask, wherein, to incide the above-mentioned irradiate light that also will pass through above-mentioned optical system on the optical system from the light of exposure light source through the attenuated type mask and to the resist layer that constitutes by the photosensitive material on the glass substrate, expose, it is characterized in that:
Above-mentioned light is the i line,
Above-mentioned attenuated type mask has the contact hole pattern that should form on the above-mentioned resist on the above-mentioned glass substrate, this contact hole pattern has 4 times contact hole arrangement pitches more than or equal to the diameter of above-mentioned contact hole,
When k1 being decided to be coefficient with value of 0.48 to 0.5 and R is decided to be the contact hole diameter that forms on the above-mentioned resist layer, above-mentioned optical system has the numerical aperture NA that utilizes following formula to obtain:
NA2＝k1×0.365/R。
20. the use described in claim 19 exposure method of phase shift mask of attenuated type, it is characterized in that:
The coherence factor σ of above-mentioned i line is 0.3 to 0.55.
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| CNA2008101751430A Division CN101452858A (en) | 2005-04-04 | 2006-04-03 | Method of producing thin film transistor and method of exposure using attenuated type mask |
| CNA2008101751426A Division CN101452960A (en) | 2005-04-04 | 2006-04-03 | Thin film transistor, integrated circuit, and liquid crystal display |
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| CN 200610071921 Pending CN1847986A (en) | 2005-04-04 | 2006-04-03 | Thin film transistor, integrated circuit, liquid crystal display, method of producing thin film transistor, and method of exposure using attenuated type mask |
| CNA2008101751430A Pending CN101452858A (en) | 2005-04-04 | 2006-04-03 | Method of producing thin film transistor and method of exposure using attenuated type mask |
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| CN108227290A (en) * | 2018-01-31 | 2018-06-29 | 京东方科技集团股份有限公司 | Mask plate, the organic protection layer obtained using it and display device |
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| US8796053B2 (en) * | 2010-12-21 | 2014-08-05 | Ultratech, Inc. | Photolithographic LED fabrication using phase-shift mask |
| CN104718498B (en) * | 2012-10-17 | 2019-12-17 | 富士胶片株式会社 | Method for producing permanent film for optical material, cured film, organic EL display device, and liquid crystal display device |
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| CN108227290A (en) * | 2018-01-31 | 2018-06-29 | 京东方科技集团股份有限公司 | Mask plate, the organic protection layer obtained using it and display device |
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