We claim:
1. A process for producing photomasks for optical lithography, which comprises the steps of:
providing a transparent substrate;
applying a layer of a mask material on the transparent substrate;
applying a layer of photoresist on the layer of the mask material, the photoresist comprising:
a film-forming polymer containing acid-labile groups to be cleaved under action of acid for liberating groups resulting in an increase in solubility of the film-forming polymer in aqueous alkaline developers, and further containing anchor groups for linkage of amplification agents;
a photo acid generator; and
a solvent;
heating the layer of the photoresist to remove the solvent resulting in a photoresist film being obtained;
writing a structure in the photoresist film using a focused electron beam resulting in an exposed photoresist film having exposed parts, in which a strong acid is liberated from the photo acid generator, and unexposed parts, in which no acid has been liberated;
heating the exposed phototresist film so that, in the exposed parts, acid-labile groups on the film-forming polymer are cleaved and polar groups are liberated resulting in a contrasted resist film being obtained;
developing the contrasted resist film using a developer resulting in a structured resist having lands and trenches disposed between the lands and in which the mask material is bare;
adding an amplification agent to the structured resist, the amplification agent having at least one reactive group which can react with the anchor groups of the film-forming polymer resulting in the amplification agent bonding to the film- forming polymer contained in the lands, so that an amplified resist is obtained;
removing any excess amplification agent; and
etching away bare mask material resulting in the structure being transferred to the layer of the mask material.
2. The process according to claim 1, which further comprises providing a quartz glass substrate as the transparent substrate.
3. The process according to claim 1, which further comprises forming the layer of the mask material as a chromium layer.
4. The process according to claim 1, which further comprises irradiating the photoresist film with the electron beam having a dose of 1 Ccm2 to 40 Ccm2.
5. The process according to claim 1, which further comprises forming the photoresist to contain a sensitizer.
6. The process according to claim 1, which further comprises forming the photoresist to contain a base.
7. The process according to claim 1, which further comprises forming the amplification agent with a silicon-containing group.
8. The process according to claim 1, which further comprises forming the amplification agent with at least two reactive groups.
9. The process according to claim 1, which further comprises applying the amplification agent in a form of a solution to the structured resist.
10. The process according to claim 1, which further comprises:
applying a layer of a photoinsensitive bottom resist to the layer of the mask material; and
applying the layer of the photoresist to the layer of the photoinsensitive bottom resist.
11. The process according to claim 1, which further comprises using protected anchor groups as the anchor groups.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A pig extraction tool for withdrawing a pig from an open end of a pig receiver of a pipeline, the tool comprising:
an elongated reach portion having a longitudinal axis defining a lengthwise direction;
a pig retrieval element carried at a respective end of the elongated reach portion for pulling of the pig from the open end of pig receiver after insertion of the respective end of the elongated reach portion into the pig receiver a sufficient distance to engage the pig retrieval element with the pig; and
a support portion that is connected to the elongated reach portion at a location spaced from the retrieval element in the lengthwise direction and that projects laterally to a side of the elongated reach portion in a lateral direction transverse to the longitudinal direction for manual support of the tool from a lateral position spaced from the elongated reach portion.
2. The tool of claim 1 comprising a hand guard on the support portion on a side thereof facing toward the pig retrieval element in the longitudinal direction.
3. The tool of claim 2 wherein the support portion comprises a main support projecting in the lateral direction and a hand grip projecting from the main support behind the hand guard at a distance from the reach portion.
4. The tool of claim 3 wherein the main support projects beyond the hand grip in the lateral direction.
5. The tool of claim 4 wherein the main support comprises a branching portion extending laterally from the reaching portion to the hand grip, and an offset handle portion located beyond the hand grip in the lateral direction and offset to a side of branching portion opposite the pig retrieval element in the longitudinal direction.
6. The tool of any one of claims 1 to 5 wherein the respective end of the elongated reach portion is extendable and retractable relative to the support portion in the longitudinal direction.
7. The tool of claim 6 comprising a telescopic mechanism operable to extend and retract the respective end of the elongated reach portion relative to the support portion.
8. The tool of claim 6 or 7 comprising lock and release mechanism operable from a distance laterally outward of the elongated reach portion to selectively unlock the reach assembly from a normally locked state in order to selectively enable extension or retraction of the respective end thereof.
9. The tool of claim 8 wherein the lock and release mechanism comprises an actuator positioned at the distance laterally outward from the elongated reach portion and operable to retract a lock member from a normal locking position engaged with a movable member of the reach assembly that is displaceable black and forth in the longitudinal direction when not engaged by the lock member.
10. The tool of claim 9 wherein the lock member is disposed internally of the support portion.
11. The tool of claim 10 wherein the actuator comprises a trigger projecting to an exterior of the support portion via a slot therein for pulling of the lock member away from the reaching portion against a biasing action of a spring that forces the lock member toward the reaching portion.
12. The tool of any one of claims 6 to 12 wherein the reach assembly comprises a first member displaceable back and forth in the longitudinal direction relative to the support portion and a second member displaceable back and forth in the longitudinal direction relative to the first member.
13. The tool of claim 12 comprising a lock unit selectively switchable between a first locking state locking the first member in place relative to the support portion and a second locking state locking the second member in place relative to the first member.
14. The tool of any one of claims 1 to 13 comprising a mirror carried on the reaching portion or the support portion in a position facing toward the retrieving element at the first end of the reaching portion.
15. A method of extracting a pig from a pig receiver of a pipeline, the method comprising using a manually operated retrieval tool to withdraw the pig from the pig receiver via an opening thereof from a location radially outward of said opening.
16. The method of claim 15 wherein the tool comprises an elongated reach portion and a support portion. connected to and extending laterally from the elongated reach portion, and the method comprises manually carrying the support portion of the tool thereof at the location radially outward of the opening of the pig receiver, and sliding and end of the longitudinal portion of the tool into the opening of the pig receiver, engaging an element at the end of the longitudinal portion of the tool with the pig, and with the pig engaged to the element, pulling the elongated reach portion of the tool, and the pig engaged thereto, out of the pig receiver via the opening.