Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Radiation sensitive composition or product or process of making
Reexamination Certificate
2000-11-08
2002-06-04
Ashton, Rosemary (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C430S315000, C430S325000
Reexamination Certificate
active
06399275
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a negative-working photolithographic patterning material capable of giving, in the manufacturing process of semiconductor devices and the like, a patterned resist layer having a relatively large film thickness, excellent heat resistance and good cross sectional profile with good developability and suitable for use as a masking layer when a substrate such as a semiconductor silicon wafer is subjected to a treatment of ion implantation, plating and the like as well as to an efficient method for the preparation of an ion-implanted and metal-plated substrates by using the same.
Several types of alkali-developable photoresist compositions are known in the prior art including positive-working photoresist compositions comprising a novolak resin and a quinone diazidosulfonate ester which are relatively inexpensive and widely employed in the manufacture of semiconductor devices and the like involving a process of metal plating, ion implantation and the like.
In recent years, negative-working chemical-amplification photoresist compositions are highlighted and employed in the above mentioned applications in respect of the high photosensitivity accomplished by virtue of the chain reaction by the acid catalyst generated from an acid-generating agent as an essential ingredient of the composition.
The above mentioned negative-working chemical-amplification photoresist compositions are formulated, in general, with an alkali-soluble resinous ingredient which can be a novolak resin prepared from m- and p-cresols in combination or a polyhydroxystyrene resin, a radiation-sensitive acid generating agent and a crosslinking agent such as an alkoxy-methylated melamine resin and the like.
When a negative-working chemical-amplification photoresist composition is used as a masking in the process of plating, however, troubles are sometimes encountered that cracks are formed in the masking, i.e. non-plating, areas of the resist layer. When the photoresist composition is used in the process of ion implantation, on the other hand, the process cannot be fully efficient because the development treatment of the photoresist layer takes a time longer than 60 seconds usually required in the ion-implantation process to obtain a satisfactorily patterned resist layer in addition to the defects of low pattern resolution and heat resistance.
In order for the patterned resist layer to serve as a mask, the thickness of the patterned resist layer should be at least 4.0 &mgr;m in the process of plating and in the range from 0.5 to 10.0 &mgr;m or, desirably, from 4.0 to 10.0 &mgr;m in the process of ion implantation in consideration of the particularly hard conditions thereof.
As is described above, the patterned resist layer used for masking in the processes of plating, ion implantation and the like must have a thickness considerably larger than the thickness of the resist layer in other general processes in the manufacture of semiconductor devices, which is usually around 1.0 &mgr;m. When the thickness of the photoresist layer is so large as mentioned above, conventional negative-working chemical amplification photoresist compositions cannot be quite satisfactory because the exposure light such as the i-line light and excimer laser beams penetrating the resist layer can hardly reach the bottom surface of the resist layer with a sufficiently high intensity so that the orthogonality of the cross sectional profile of the patterned resist layer can hardly be high enough.
In compliance with the incentive toward cost reduction in the industries in general, on the other hand, development of an inexpensive photoresist composition is an important problem in the electronic industry. Accordingly, it is eagerly desired for the process of plating to develop an inexpensive negative-working chemical amplification photoresist composition suitable for the formation of a photoresist layer of a large thickness capable of giving a patterned resist layer having a cross sectional profile of good orthogonality and still free from occurrence of cracks in the plating process. It is also desired for the process of ion implantation to develop a negative-working chemical amplification photoresist composition which satisfies the requirement for the time taken for development not exceeding 60 seconds in addition to the requirements for the process of plating.
SUMMARY OF THE INVENTION
The present invention accordingly has an object, in view of the above described problems and disadvantages relative to the photoresist compositions as a masking material in the processes of ion implantation and plating onto a substrate such as a semiconductor silicon wafer, to provide an inexpensive negative-working photolithographic patterning material capable of giving a masking layer of a large thickness having excellent heat resistance and good orthogonality of the cross sectional profile along with developability within a short time and high pattern resolution.
The present invention also has an object to provide a method for the preparation of a patternwise ion-implanted or metal-plated substrate by utilizing the above mentioned patterning material.
Thus, the negative-working photolithographic patterning material provided by the present invention comprises:
(a) a substrate; and
(b) a negative-working photoresist layer having a thickness in the range from 4.0 to 10.0 &mgr;m and formed on the surface of the substrate from a negative-working chemical amplification photoresist composition comprising, as a uniform solution in an organic solvent:
(A) 100 parts by weight of an alkali-soluble resin which is a m-cresol novolak resin as a product of an acid-catalyzed condensation reaction of m-cresol and formaldehyde;
(B) from 1 to 20 parts by weight of a radiation-sensitive acid-generating compound; and
(C) from 3 to 50 parts by weight of a crosslinking agent which is a compound having functional groups selected from hydroxyalkyl groups and alkoxyalkyl groups.
The alkali-soluble resin as the component (A) can be a combination of the m-cresol novolak resin and a polyhydroxystyrene resin in a weight proportion of at least 5:5 or, preferably, in the range from 5:5 to 9:1.
The present invention has a further object to provide a method for the preparation of a patternwise ion-implanted or metal-plated substrate which comprises the steps of:
(1) patternwise exposing the photoresist layer of the above defined patterning material to actinic rays;
(2) subjecting the patterning material after patternwise exposure to a heat treatment;
(3) developing the patterning material after the heat treatment to a development treatment with an aqueous alkaline developer solution to form a patterned resist layer; and
(4) conducting ion implantation or metal-plating with the patterned resist layer as a mask.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As is described above, the photolithographic patterning material of the present invention is characterized by the photoresist layer having a specific thickness and formed on the surface of a substrate from a specific negative-working chemical amplification photoresist composition comprising the components (A), (B) and (C) as the essential ingredients.
In the photoresist composition used for the formation of the patterning layer in the inventive patterning material, the component (A) is an alkali-soluble resin such as a m-cresol novolak resin prepared by the polycondensation reaction of m-cresol and formaldehyde in the presence of an acid catalyst.
As is well known, the above mentioned m-cresol novolak resin is an inexpensive resinous material having high solubility in an aqueous alkaline medium. This resin, however, is not or rarely employed as a resinous ingredient in the conventional photoresist compositions because the alkali-solubility of the resin is so high as to cause an unduly large film thickness reduction in the unexposed areas by the alkali development and the patterned resist layer can hardly have a good orthogonal cross sectional profile. Accordingly, the novolak resin use
Haraguchi Takayuki
Morio Kimitaka
Sugeta Yoshiki
Ashton Rosemary
Tokyo Ohka Kogyo Co. Ltd.
Wenderoth Lind & Ponack LLP
LandOfFree
Negative-working photolithographic patterning material and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Negative-working photolithographic patterning material and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Negative-working photolithographic patterning material and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2919110