Abstract: A method of forming a high transmittance attenuated phase-shifting mask, comprising the following steps. A patterned shifter blank including a patterned shifter layer, having a first variable transmittance and a first phase angle overlying a partially exposed transparent substrate is provided. The partially exposed transparent substrate is etched for a first predetermined time to form trenches therein having a predetermined depth, increasing the first variable transmittance and the first phase angle to a second variable transmittance and a second phase angle, respectively. The shifter layer is treated with an aqueous solution of NH4OH:H2O2 for a second predetermined time, increasing the second variable transmittance to a third and final, predetermined variable transmittance, and decreasing the second phase angle to a third phase angle. Whereby the third phase angle is substantially equal to the initial phase angle of said shifter layer.

Abstract: A method is described for using computer aided design data for contact holes in a background, such as an opaque background or a phase shifting background, to generate computer aided design data for fabricating a mask an outrigger pattern. The outrigger pattern mask has contact holes surrounded by a first border of opaque material and the first border of opaque material surrounded by a third border of attenuating or 100% transmittance phase shifting material. The third border of attenuating or 100% transmittance phase shifting material is surrounded by opaque material. The design data for the contact hole pattern, a background pattern, a first correction pattern, and a second correction pattern are combined in a computer processor to generate final data. The final data is used to fabricate the mask.

Abstract: This invention describes an attenuating phase shifting mask, a method of forming the attenuating phase shifting mask, and a method of using the attenuating phase shifting mask to expose a contact hole pattern having both dense and isolated contact holes on a layer of photosensitive dielectric. The mask has a rim of first attenuating phase shifting material, having a first transmittance and providing a phase shift of 180°, surrounding the dense holes and a rim of second attenuating phase shifting material, having a second transmittance and providing a phase shift of 180°, surrounding the isolated holes. The second transmittance is greater than the first transmittance. The dense holes have a duty ratio of less than 2.0 and the isolated holes have a duty ratio of greater than or equal to 2.0.

Abstract: A method of forming a high transmittance attenuated phase-shifting mask blank, comprising the following steps. An attenuated phase-shifting mask is provided that includes a shifter layer overlying a transparent substrate. The attenuated phase-shifting mask having a first transmittance and an initial phase angle. The attenuated phase-shifting mask and more specifically the shifter layer is treated with an aqueous solution of NH4OH:H2O2 for a first predetermined time increasing the first transmittance to a second transmittance and decreasing the initial phase angle to a second phase angle. The attenuated phase-shifting mask is then treated with a selected acid or base for a second predetermined time increasing the second transmittance to a third, predetermined transmittance and increasing the phase angle to a third, predetermined phase angle. The third phase angle is preferably substantially identical to the initial phase angle.

Abstract: A method for modulating the phase angle of a phase shift mask employed in deep ultraviolet (DUV) photolithography. There is provided a quartz substrate within which may be formed an engraved pattern, and upon which is formed a patterned phase shift layer. The phase angle of the phase shift layer upon the quartz substrate may be incrementally increased or decreased by subtractive etching of the phase shift layer and quartz substrate of the phase shift mask in an alkaline solution at a selected temperature and concentration for a period of time.

Abstract: A simple, cost-effective method for forming a lithography mask with a directly imaged portion and an attenuated, phase shifted portion. In particular, the use of such a method for forming an outrigger-type phase shift mask. The mask is formed on a blank consisting of a transparent quartz substrate over which is an attenuating phase shift layer and an optically opaque layer, by a process that produces a pattern in an E-beam sensitive resist with two different E-beam energy depositions. The higher energy deposition is used to form the main pattern, while the lower energy deposition forms the pattern for the outrigger.

Abstract: A method of forming attenuating phase shifting masks having an opaque border on a mask blank having a layer of attenuating phase shifting material overlaying a transparent mask substrate, a layer of opaque material overlaying the layer of attenuating phase shifting material, and a layer of resist overlaying the layer of opaque material. First pattern regions are exposed in the resist using an electron beam and a first exposure dose. Second pattern regions surrounding each of the first pattern regions, are left unexposed providing a width of unexposed resist around each of the first pattern regions. Third pattern regions surrounding each of the second pattern regions are exposed in the resist using the same electron beam and a second exposure dose, which is less than the first exposure dose. A border region of resist around the outer periphery of the mask is not exposed.

Abstract: A mask combining an alternating phase shift part and an attenuating phase shift part on a single blank and a method of forming said mask. The method involves fewer processing steps, fewer layers of material and is more cost effective than other methods in the current art. A central reason for the simplicity of the method is the use of different intensity levels of E-beam exposure in a single resist layer and achieving phase shifts by transmitting radiation through alternating regions of the same transparent substrate that are etched and not etched.

Abstract: A method is disclosed for employing direct electron beam writing in the lithography used for forming step-profiles in semiconductor devices. The number of steps in the profiles are not limited. An electron beam sensitive resist is formed over a substrate. The resist is then exposed to a scanning electron beam having precise information, including proximity effect correction data, to directly form stair-case-like openings in the resist. The highly accurately dimensioned step-profiles are then transferred into the underlying layers by performing appropriate etchings. The resulting structures are shown to be especially suitable for forming damascene interconnects for submicron technologies.

Abstract: A method of source/drain and LDD implantation using a single implantation step is described. A gate electrode is formed in an active area on surface of a semiconductor substrate. The gate electrode and the semiconductor substrate are covered with a resist layer. The resist layer in the active area is exposed to lithography source, such as electron-beam direct writing, or other process, wherein a portion of the resist layer overlying the planned LDD regions is exposed to a first energy and a portion of the resist layer overlying the planned source/drain regions is exposed to a second energy greater than the first energy and wherein a portion of the resist layer outside of the active area is not exposed. The resist layer is developed to leave a resist mask having a first thickness in areas not exposed and to leave a resist mask having a second thickness in areas exposed to the first energy and to leave no resist mask in areas exposed to the second energy.

Abstract: A mask and method of forming a mask for forming electrode patterns having both closely spaced lines and lines with greater separation between them. The mask uses a pattern formed using attenuating phase shifting material for the region of the mask with lines with greater separation and a binary pattern formed using opaque material in the region of the mask with closely spaced lines. The mask design data is used to determine the mask regions using attenuating phase shifting material and the regions of the mask using a binary pattern. The mask is illuminated using off axis illumination, preferably quadrapole off axis illumination. The mask is formed using electron beam exposure of a resist using more than one exposure dose so that only one layer of resist is required to form the two regions of the mask one using attenuating phase shifting material and one using a binary pattern.

Abstract: A method and apparatus for inspecting photomasks having phase shifting elements which shift the phase of light but are otherwise transparent. A coherent light source is directed through a mask to be inspected, through an objective lens, through an 180.degree. phase shifting unit, and to an image divider. The coherent light source is also directed through a transparent reference substrate to the image divider. The mask to be inspected is formed on a transparent mask substrate having the same thickness and formed from the same material as the transparent reference substrate. The intensity of the light exiting the image divider is proportional to the square of the cosine of 1800 plus the phase angle between the light exiting the reference substrate and the light exiting the mask under test. The light exiting the image divider is directed to a CCD image sensor. An image computer compares the output of the CCD image sensor with an image formed from the image database and identifies defects in the mask under test.

Abstract: A method is described of forming phase shifting masks using a single layer of resist and a single electron beam exposure step with two different exposure doses. A layer of resist is formed on a layer of opaque material formed on a transparent mask substrate. A first pattern is exposed in the entire thickness of the layer of resist, using a first exposure dose, and a second pattern is exposed in the top portion of the layer of resist, using s second exposure dose smaller than the first exposure dose. The layer of resist is then developed and baked. The first pattern in then etched in the layer of opaque material and a first thickness of the transparent mask substrate. The first thickness of the transparent mask substrate provides a 180.degree. phase shift to light used to transfer the mask pattern to an integrated circuit wafer. Part of the layer of resist is then etched away transferring the second pattern to the resist that remains. The second pattern is then etched in the layer of opaque material.

Abstract: A mask and method of forming a mask for forming a closely spaced array of contact holes and larger isolated holes in an integrated circuit wafer. The mask provides a binary mask section for the formation of the closely spaced array of contact holes where the depth of focus is not a problem thereby avoiding problems due to side lobe effect. The mask also provides a ring type attenuating phase shifting mask for the formation of isolated larger holes where improved depth of focus is required, thereby also avoiding the problems due to side lobe effect in this region.

Abstract: A method of correcting, or compensating for errors encountered in the transfer of patterns is disclosed for use with high resolution e-beam lithography. In a first embodiment, optical proximity effects are incorporated into the e-beam proximity effects by superimposing the two effects to arrive at a compensated dosage level database to produce the desired patterns. In a second embodiment, etching effects are also superimposed on the previous driving database by compensating the e-beam proximity data twice, that is, by over correcting it, to further improve the transfer of patterns without the undesirable effects. It is shown that corrections for a number of other process steps can also be incorporated into the database that drives the e-beam lithography machine in order to achieve high resolution patterns of about one-quarter-micron technology.

Abstract: A electrical connection structure pattern according to the present invention includes a relatively dense first electrical connection structure area to a second electrical connection structure area. First, the electrical connection structure pattern is expensed to generate a first dummy pattern. The area of the first dummy pattern is larger than that of electrical connection structure pattern. Next, a second dummy pattern is generated by narrowing the line width of the first dummy pattern. A third dummy pattern is obtained by using CAD. The area of the third dummy pattern is smaller than that of the second dummy pattern, but larger than that of the electrical connection structure pattern. A fourth dummy pattern is generated by using CAD to remove the overlap area between the second dummy pattern and the third dummy pattern.

Abstract: An apparatus for die to die inspection of masks having transparent phase shifting elements and a method of die to die inspection of masks having transparent phase shifting elements. Light from a light source is directed through a transparent mask substrate and a phase shifting mask element to a first objective lens, and through the transparent mask substrate and another phase shifting mask element to a second objective lens. Light from the first objective lens is then given a 180.degree. phase shift by a phase adjustment unit. Light from the phase adjustment unit and the second objective lens is combined at a split mirror and directed to a detector. The method makes use of the fact that the intensity of the light at the detector is proportional to the square of the cosine of one half of the phase angle between the light from the phase adjusting unit and light from the second objective lens. If the intensity of light reaching the detector is not zero, or very small, the mask has a defect.

Abstract: A method of forming a rim type attenuating phase shifting mask which requires only one resist layer and developing the resist using a single developing solution. A transparent mask substrate has a layer of attenuating phase shifting material, a layer of opaque material, and a layer of resist material formed thereon. The layer of resist is exposed to a first pattern using a first exposure dose and a second pattern using a smaller second exposure dose. The resist is developed for a first time forming the first pattern in the entire layer of resist and the second pattern in the top portion of the layer of resist. The first pattern is then etched in the layer of opaque material using the first pattern in the layer of resist as a mask. In one embodiment the first pattern is then etched in the layer of attenuating phase shifting material, the resist is partially etched using an O.sub.

Abstract: A mask and method of systematically laying out the mask for test patterns in the frame cell region of an attenuating phase shifting mask are described. An array of sub-resolution contact holes are used in the border regions of the mask to prevent over exposure of photoresist in the regions between the device regions on a wafer due to side lobe effect. The mask and method provide for a buffer distance surrounding the features of the test patterns. The buffer distance is free of sub-resolution contact holes. When the buffer distance is correctly chosen problems due to side lobe effect at the frame cell portion of the mask are prevented.

Abstract: The present invention discloses a novel method for interlayer corrections for photolithographic patterns that are reproduced on a wafer surface capable of correcting not only the optically-induced proximity effect but also the process-induced proximity effect. In the method, a conventional optical proximity correction is first performed on a photomask, the corrected photomask is then used to produce a pattern on a wafer surface. The various critical dimensions bias values at a multiplicity of locations are then measured and fed back to the computer aided design data file for the photomask for producing patterns that are corrected for both optically-induced and process-induced proximity effect on a wafer surface.