shorter curing times. Following this curing step, the under› layer surface may optionally be passivated by treatment with a passivating agent such as a disilazane compound, such as hexamethyldisilazane, or by a dehydration bake step to remove any adsorbed water. Such passivating treatment with a disilazane compound is typically performed at 120° C. 

[0046] After curing of the coating layer comprising the condensed polymer to form an underlayer, one or more processing layers, such as photoresists, hardmask layers, bottom antireflective coating ( or BARC) layers, and the like, may be disposed on the underlayer. For example, a photo› resist layer may be disposed, such as by spin coating, directly on the surface of the underlayer. Alternatively, a BARC layer may be coated directly on the underlayer, followed by curing of the BARC layer, and coating a photoresist layer directly on the cured BARC layer. In another alternative, an organic underlayer is first coated on a substrate and cured, a condensed polymer layer of the invention is then coated on the cured organic underlayer, the coating layer is then cured to form an underlayer, an optional BARC layer may be coated directly on the underlayer, followed by curing of the optional BARC layer, and coating a photoresist layer directly on the cured BARC layer. A wide variety of photoresists may be suitably used, such as those used in 193 nm lithography, such as those sold under the EPIC™ brand available from Dow Electronic Materials (Marlborough, Mass.). Suitable photoresists may be either positive tone development or negative tone development resists, or may be conventional negative resists. The photo› resist layer is then imaged ( exposed) using patterned actinic radiation, and the exposed photoresist layer is then devel› oped using the appropriate developer to provide a patterned photoresist layer. The pattern is next transferred from the photoresist layer to any optional BARC layer, and then to the underlayer by an appropriate etching technique, such as dry etching with an appropriate plasma. Typically, the photore› sist is also removed during such etching step. Next, the pattern is transferred to any organic underlayer present using an appropriate technique, such as dry etching with 0 2 plasma, and then to the substrate as appropriate. Following these pattern transfer steps, the underlayer, and any optional organic underlayers are removed using conventional tech› niques. The electronic device substrate is then further pro› cessed according to conventional means. 

[0047] The present compositions provide underlayers hav› ing good etch resistance and high silicon content (s45% Si, and preferably from 0.5 to 30% Si). The coating layers comprising the present condensed polymers and underlayers described herein are wet strippable. By "wet strippable" is meant that the coating layers and underlayers of the inven› tion are removed, and preferably substantially removed (;;,;95% of film thickness), by contacting the coating layer or underlayer with conventional wet stripping compositions, such as: (1) an aqueous base composition, such as aqueous alkali (typically about 5%) or aqueous tetramethylammo› nium hydroxide (typically ;;,;5 wt %), (2) aqueous fluoride ion strippers such as ammonium fluoride/ammonium bifluo› ride mixtures, (3) a mixture of mineral acid, such as sulfuric acid or hydrochloric acid, and hydrogen peroxide such as a mixture of concentrated sulfuric acid+30% hydrogen per› oxide, or (4) a mixture of ammonia, water and optionally hydrogen peroxide. A particular advantage of the present polymers, and particularly of the present underlayers, is that they are wet strippable upon contact with a mixture of 

ammonia and hydrogen peroxide. A wide range of ammonia and water mixtures may be used. A suitable mixture of ammonia, water and hydrogen peroxide is a mixture of ammonia+hydrogen peroxide+water in a weight ratio of 1:1:5 to 1:10:50, such as ratios of 1:1:10, 1:1:40, 1:5:40, 1:1:50, or 1:8:50. Preferably, ;;,;97%, and more preferably ;;,;99%, of the film thickness of the polymer layer or under› layer is removed by contacting the polymer layer or siloxane underlayer with either (i) mixture of sulfuric acid and hydrogen peroxide or (ii) a mixture of ammonium hydroxide and hydrogen peroxide. Such wet stripping of the present underlayers may be performed at any suitable temperature. A particular advantage of the present compositions, and particularly of the present underlayers, is that they are wet strippable at lower temperatures, such as from 20 to 30° C., preferably from 22 to 28° C., and more preferably 25° C. 

[0048] Another advantage of the present polymer layers is that they are easily removed to allow re-work of the sub› strate, such as a wafer. In such a re-work process, a com› position described above comprising one or more condensed polymers of the invention is coated on a substrate. The coated polymer layer is then optionally soft-baked, and then cured to form an underlayer. Next, a photoresist layer is coated on the underlayer, and the resist layer is imaged and developed. The patterned resist layer and the underlay er may then each be removed to allow the wafer to be re-worked. The underlayer is contacted with any of the above-described wet stripping compositions, such as aqueous tetramethyl› ammonium hydroxide compositions (typically ;;,;5 wt%) and aqueous fluoride ion strippers such as ammonium fluoride/ ammonium bifluoride mixtures, at a suitable temperature to remove the underlayer to provide the substrate free, or substantially free, of underlayer and readily undergo addi› tional re-work as may be necessary. Such re-work includes coating another layer of the present condensed polymers on the substrate and processing the polymer coating as described above. 

[0049] A further advantage provided by the invention is a silicon-containing underlayer on a substrate, the silicon› containing underlayer comprising one or more condensed polymers having an organic polymer chain having pen› dently-bound moieties having an acidic proton and a pKa in water from -5 to 13 and having pendently-bound siloxane moieties, wherein the silicon-containing underlayer has a removal rate of greater than 100 A/sec. when contacted with a mixture of 30% NH$_{4}$OH/30% H$_{2}$Oiwater in a ratio of 1/1/5 to 1/8/50 wt/wt/wt for a period of time from 30 seconds to 5 minutes at temperature in the range of from room temperature to 70° C. Preferably, such silicon-con› taining underlayers have a removal rate of at least 125, more preferably at least 150, yet more preferably at least 200, and even more preferably at least 250 A/sec. Preferably, the polymers comprise as polymerized units one or more second unsaturated monomers as described above. 

[0050] A solution oftert-butyl methacrylate (tBMA), (59. 99 g), methacrylic acid (MAA), (29.06 g) and 3-(trimethox› ysilyl)propyl methacrylate (TMSPMA), (20.95 g) dissolved in 1,3-dioxolane (85.4 g) and a solution of V-65 initiator (20.95 g) dissolved in 2:1 v/v tetrahydrofurane/acetonitrile (20.9 g) were both added dropwise over 2 hours to 1,3- dioxolane (199 g) at 75° C. under a nitrogen blanket. After addition, the reaction mixture was held at 75° C. for an 

## EXAMPLE 1 

