CN1204597C - How to make a phase shift mask - Google Patents

Abstract

A method for making phase shift mask includes forming thin mask layer on side wall of patterned photoresistive layer to cover chromium layer, making phase shift layer and forming phase shift opening on transparent base plate by using patterned photoresistive layer and mask layer as mask. The chromium layer under the mask layer can be accurately self-aligned to the phase shift layer, so that alignment errors caused by multiple times of photoetching are avoided, the accuracy of mask patterns is improved, one photoetching step can be reduced, and the manufacturing cost of the mask is reduced.

Description

The manufacture method of phase-shift mask

Technical field

The present invention relates to a kind of manufacture method of mask, and, can reduce the number of times that mask carries out photoetching, and form accurate mask pattern particularly relevant for the manufacture method of a kind of phase-shift mask (PSM).

Background technology

In semi-conductor industry, the making of photoresistance pattern is to utilize photolithographic exposure tool such as stepper or scanning machine, and exposure is to define required pattern on photosensitive material.Its step at first on the semiconductor-based end after the coating one deck photoresist layer, utilize exposure tool with the graphic pattern projection on the mask to photoresist layer, use developer to develop the part of photoresist layer exposure then, make photoresist layer show pattern on the mask.Utilize this patterned light blockage layer to be mask afterwards, carry out the technology that follow-up etching or ion inject.

Mask is substrate with the transparent plate generally, forms opaque circuit and define required pattern on flat board.Transparent plate generally is made of quartz, and opaque circuit then defines required circuit pattern by etching chromium (Chrome) layer.With the incident light irradiation mask that radiating light source sends, the pattern of process mask covers and x-ray diffraction forms image, and through optical projection system virtual image is incident upon on the photoresist layer.About exposure technique its illustrate further can be with reference to pages274-276 of VLSI Technology edited by S.M.Sze ( 1983).

Yet, because the complexity of semiconductor element improves, relatively increase the complexity of mask pattern, make the pattern crypto set more on the mask, the distance between the light tight zone shortens more, causes numerical aperture (Numerical Aperture) to reduce.When numerical aperture reduces, when light penetrated mask pattern, the x-ray diffraction phenomenon can take place, this makes conventional lithographic techniques to promote.

Along with dwindling of semiconductor dimensions, the parts number that unit are is made increases, and makes the required average unit cost of semiconductor element and reduces gradually, and also increase prouctiveness.In order to produce littler size, need more useful exposure tool to obtain the higher resolution and the darker depth of focus.For the fixed light source of setted wavelength, how promoting the resolution and the depth of focus is a quite problem of difficulty.

Among numerous solutions, one of them promptly be to use phase-shift mask (Phaseshifting mask, PSM).PSM makes the phase shift layer on traditional mask, utilize phase delay 180 degree of phase shift layer with incident light, phase place in contrast to original incident light, usually by using the different-thickness or the photic zone of different refractivity to reach, make the incident light of incident light that penetrates the phase shift layer and the mask element that is close to form destruction interference, form wire pattern, and improve the resolution and the depth of focus by this.Therefore, how promoting the resolution and the depth of focus of PSM more further, is technical task anxious to be overcome.

Summary of the invention

Therefore, the invention provides a kind of manufacture method of phase-shift mask, between photic zone and phase shift layer, form light non-transmittable layers, promote the analytic ability of mask on the border.And the present invention utilizes technique of alignment making mask pattern voluntarily, the accuracy that can promote pattern on the mask, and only use lithography step one, the deviation of the alignment problem that repeatedly lithography step caused can be avoided, and cost of manufacture can be reduced.

From a viewpoint, the invention provides a kind of manufacture method of phase-shift mask, comprise the following steps at least.At first on transparency carrier, form light non-transmittable layers and patterning photoresist layer in regular turn.Then on light non-transmittable layers and patterning photoresist layer, cover one deck mask layer, remove the part mask layer then, be left the part on patterning photoresist layer sidewall, and the light non-transmittable layers part under exposing.Remove the expose portion of light non-transmittable layers and beneath partially transparent substrate afterwards, in transparency carrier, form the phase shift opening.Remove patterning photoresist layer and beneath light non-transmittable layers then.

From another viewpoint, the invention provides a kind of manufacture method of phase-shift mask, the method comprises the following steps at least.At first on transparency carrier, form light non-transmittable layers, then on light non-transmittable layers, form the patterning photoresist layer.The patterning photoresist layer that expands then increases a dilation, the light non-transmittable layers at overlay pattern photoresist layer edge on the sidewall of patterning photoresist layer.Remove the expose portion of light non-transmittable layers and beneath transparency carrier afterwards, form a phase shift opening.Remove the beneath light non-transmittable layers of patterning photoresist layer and patterning photoresist layer then.

From another viewpoint, the invention provides a kind of manufacture method of phase-shift mask, the method comprises the following steps at least.At first on transparency carrier, form light non-transmittable layers, then on light non-transmittable layers, form first mask layer.On the sidewall of first mask layer, form second mask layer then, cover the part light non-transmittable layers at the first mask layer edge.Remove the expose portion of light non-transmittable layers and beneath partially transparent substrate afterwards, form a phase shift opening.Remove the beneath light non-transmittable layers of first mask layer and first mask layer then.

The invention provides a kind of manufacture method of phase-shift mask, on the sidewall of patterning photoresist layer, form mask layer, can aim at the chromium layer pattern of producing between phase shift opening and phase shift layer and the photic zone voluntarily, not only promote the accuracy of mask pattern, and only need one lithography step, can significantly reduce the cost of manufacture of mask.

Description of drawings

The present invention is described in detail below in conjunction with embodiment and accompanying drawing:

Figure 1A-1F illustrates the technological process profile according to the phase shift mask of preferred embodiment of the present invention.

Figure 1A illustrates having on the transparency carrier of light non-transmittable layers and forms patterned light blockage layer.

Figure 1B illustrates one deck mask layer that forms conformal (conformal) on transparency carrier.

Fig. 1 C illustrates and eat-backs mask layer, till coming out to photoresist layer and light non-transmittable layers.

Fig. 1 D illustrates and removes the light non-transmittable layers that exposes and transparency carrier to a degree of depth that is positioned under it, to form the phase shift opening.

Fig. 1 E illustrates and removes photoresist layer and the light non-transmittable layers that is positioned under it.

Fig. 1 F illustrates and removes remaining mask layer.

Symbol description among the figure:

100 substrates 102,102a, 102b light non-transmittable layers

104 photoresist layers, 105 sidewalls

106,106amask layer 108 phase shift openings

110 pattern openings

Embodiment

Figure 1A-1F is the technology generalized section that illustrates a preferred embodiment of the present invention.Please refer to Figure 1A, atransparency carrier 100 at first is provided, be generally quartz base plate.Then form a lightnon-transmittable layers 102 ontransparency carrier 100, this lightnon-transmittable layers 102 can be chromium (Cr) layer, chromium oxide (CrO) layer, or other light tight material.Then on lightnon-transmittable layers 102, form one deck patternedlight blockage layer 104, be covered in the transmission region of incident light,, be used to make mask pattern as mask layer.Patterningphotoresist layer 104 can use traditional photoetching technique to form, at first coating one deck photoresist layer on lightnon-transmittable layers 102 revolves optically active compounds (PAC) by sense and is constituted, and then exposes, steps such as development, baking, remove unwanted part, on photoresist layer, form required pattern.

Then please refer to Figure 1B, then ontransparency carrier 100, form the thin mask layer 106 of one deck, cover on lightnon-transmittable layers 102 and the patterning photoresist layer 104.Mask layer 106 is preferably along the surface profile oftransparency carrier 100 and rises and falls, and is conformal with patterningphotoresist layer 104 and lightnon-transmittable layers 102, the 0.01-0.5 that its thickness generally is about live width doubly between, but must decide on actual mask pattern design.And by the technology of suitable control formation mask layer 106, it forms thickness can be very accurate, even can reach several dusts (angstrom).

The selected material of mask layer 106 with and forming method thereof multiple choices are arranged, only think example at this, be not in order to limit the present invention.For example, mask layer 106 can be to use chemical vapour deposition technique (CVD) silicon oxide layer that forms that deposits, then butphotoresist layer 104 can be selected the collocation of silanization (silylatable) photoresist for use, and carry out silanization (silylation) step, increase the tack betweenphotoresist layer 104 and the mask layer 106.Mask layer 106 also can use polymer, as bottom antireflection (BARC) polymer, forms with method of spin coating (Spin-on coating).

Please refer to Fig. 1 C, carry out the anisotropic dry ecthing then, remove the part of mask layer 106 onphotoresist layer 104 and lightnon-transmittable layers 102, the lightnon-transmittable layers 102 under exposing, only be left thepart mask layer 106a onphotoresist layer 104sidewalls 105, as the mask of subsequent.Because the thickness of mask layer 106 is quite thin, relatively also suitable narrow and very accurate of the width of themask layer 106a onphotoresist layer 104sidewalls 105 helps the control to live width.

In addition, except aforesaid way, also can utilize the photoresistance expansion technique to substitute,photoresist layer 104 is expanded to both sides, increase the dilation ofmask layer 106a, increase the lightnon-transmittable layers 102 that coversphotoresist layer 104 edges by this.For example,photoresist layer 104 optional usefulness have the hydrophilic resin (hydrophilic resin) of swelling properties, carry out improving resolution photoetching (Resolution Enhancement Lithography Assisted by ChemicalShrink by chemical enrichment method, RELACS) technology,photoresist layer 104 is expanded, increase the part ofmask layer 106a, shown in Fig. 1 C, as the mask of subsequent etch light non-transmittable layers 102.The method that photoresistance is expanded for example, can be used solvent impregnated or handles to have organic photoresist, such as being saturated aliphat hydroxyl class or aromatic series hydroxyl class etc., forms the light acid reaction, and photoresist is expanded.

Please refer to Fig. 1 D, be mask withmask layer 106a then withphotoresist layer 104, the expose portion of etching lightnon-transmittable layers 102, form light non-transmittable layers 102a, and thetransparency carrier 100 under the continuation etching, suitably control its etching technique and carve the degree of depth, up to forming phase shift opening 108, as the part of mask pattern, make thetransparency carrier 100 of position under phase shift opening 108 form the phase shift layer.Behind the phase shift layer under the incident light transmission phase is removedmouth 108, its phase place is with anti-turnback.

Please refer to Fig. 1 E, removephotoresist layer 104 afterwards, it is preferable that its removing method divests mode with wet type, avoids destroying established phase shift opening 108.Remove the part light non-transmittable layers 102a under thephotoresist layer 104 afterwards, form light non-transmittable layers 102b, and form pattern openings 110, as the part of mask pattern.When incident light transmission pattern openings 110, it still keeps original phase place.Because when making phase shift opening 108, do not need another road lithography step, so phase shift opening 108 and pattern openings 110 problem that can not reduce because of the distortion of the mask pattern that alignment error caused between the above lithography step in two roads and live width analytic ability.

Please refer to Fig. 1 F, remove themask layer 106a on the light non-transmittable layers 102b at last, form phase-shift mask of the present invention.Behind phase shift opening 108 and pattern openings 110 on the incident light transmissiontransparent substrates 100, transmitted light phasing back 180 degree byphase shift opening 108, form destruction interference with transmitted light by pattern openings 110, weaken penetrating light intensity on both borders, and by on the border, forming light non-transmittable layers 102b, can further reduce the penetrating light intensity on both borders, the resolution of promoting mask by this.

In sum, the invention provides a kind of manufacture method of phase-shift mask, utilize mask layer to aim at voluntarily, only use lithography step one, avoid the deviation of the alignment problem that repeatedly lithography step caused, promote the accuracy of mask pattern, and can reduce cost of manufacture.

As understood by those skilled in the art, the above is preferred embodiment of the present invention only, is not in order to limit protection scope of the present invention; All other do not break away from the equivalence of being finished under the disclosed spirit and changes or modification, all should be included in the scope of this patent.

Claims (8)

1. the manufacture method of a phase-shift mask comprises the following steps: at least

On a transparency carrier, form a light non-transmittable layers and a patterning photoresist layer in regular turn;

Form a mask layer and cover this light non-transmittable layers and this patterning photoresist layer;

Eat-back this mask layer, till the upper surface that is positioned at this patterning photoresist layer under this mask layer and this light non-transmittable layers comes out;

Remove the expose portion and this transparency carrier to one degree of depth that is positioned under it of this light non-transmittable layers, form a phase shift opening; And

Remove this beneath light non-transmittable layers of this patterning photoresist layer and this patterning photoresist layer.

2. the method for claim 1, it is characterized in that: the material of this light non-transmittable layers is selected from the group of being made up of chromium, chromium oxide and their combination.

3. the method for claim 1, it is characterized in that: the material of this mask layer comprises silica.

4. the method for claim 1, it is characterized in that: the material of this mask layer comprises polymer.

5. the method for claim 1, it is characterized in that: the method that forms this mask layer comprises chemical vapour deposition technique.

6. the method for claim 1, it is characterized in that: the method that forms this mask layer comprises method of spin coating.

7. the method for claim 1 is characterized in that: the method for removing this mask layer of part comprises the anisotropic dry ecthing.

8. the method for claim 1 is characterized in that: the width of this mask layer on this patterning photoresist layer sidewall for the 0.01-0.5 of this patterning photoresist layer width doubly.

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