Конструирование и технология электронно-вычислительной аппаратуры (1065432), страница 3

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Oxide layer- окисный слой

Oxide film – окисная пленка

Polymer –полимер

polymer chain –полимерная цепочка

Preliminary exercises:

Ex. 1.Вспомните значение префиксов –un-; non-; re-; semi-.

Образуйте с их помощью производные от следующих слов и дайте их перевод:

Un-: exposed, coated, equal, covered, common

Non-: transparent; effective

Re-: move, place, do, read

Semi-: conductor, circle

Ex.2 Переведите однокоренные слова, обращая внимание на значение суффиксов и префиксов.

Process, v –(обрабатывать) process, processing, processor

Move, v(двигать(ся)) remove, removal, removed

Coat, v (покрывать) – coating, coated

Apply, v (применять) –applied, application, applicable

Vary, v (различаться) – variety, variable, variability, variation, various

Dissolve, v (растворять) dissolvable, dissolvent, solution

Ex. 3 Прочитайте и переведите следующие слова без словаря, учитывая их интернациональную основу.

Photographic, photoresist, film, polymer, polymerize, quartz, lamp

Ex. 4 Прочитайте первые три абзаца текста А и скажите, в чем состоит задача литографии.

Text A

Masking

1. Masks hold an important place n the technology of semiconductor devices. They serve to ensure the local character of deposition, doping, etching, and, in some cases, epitaxial growth. Of all the techniques used for mask fabrication photolithography heads the list. Photolitography, also called photomasking or photoengraving uses photoresists which are a variety of photoemulsions applied in conventional photography. Photoresists are sensitive to ultraviolet light and hence they can be processed in a slightly darkened room.

2. Photoresists come in negative-acting and positive- acting types. The first polymerize under light and become stable to etchants (acidic or alkaline solutions); after selective exposure to light the unexposed portions will be soluble as is the case for a common photographic negative. On the contrary, in positive photoresists the light destroys polymer chains so the etch will dissolve the exposed portions.

3. The structure containing the pattern of the future oxide mask is known as a photomask. This is a thick glass plate one side of which is coated with a thin non-transparent film having the desired circuit pattern in rhe form of transparent openings. These openings or pattern elements are equal in size to the desired integrated elements, which can be as small as 20 to 50 … or even 2 or 3 …

4. The photolitho technique for opening windows in the mask that covers a silicon wafer consists of a number of steps. A small drop of photoresist PR is placed on the oxidized surface and the wafer is rotated to spread the photoresist over its surface in an even film about 1 … thick. The film is then left to dry hard. Next the photomask (FM) with its pattern facing the photoresist is placed over the wafer and exposed to the light of a quartz lamp. The photomask is the taken off.

5. If the process makes use of a positive photoresist then after its development and fixing (hardening and heat treatment) the photoresist layer will have windows in the areas which correspond to the transparent portions on the photomask. We thus have transferred image of the pattern from the photomask to the photoresist. The photoresist layer is now the mask that tightly adheres to the oxide layer.

6. In the next step an etchant is applied to remove the oxide layer through the windows in the photoresist mask as far as the silicon surface (which is resresistant to the etchant used) and thus to open the windows in the oxide thereby transferring the pattern from the photoresist to the oxide layer. The final step involved in the photomasking process comes to etching away the remaining photoresist leaving intact the oxide mask with windows. The wafer is now ready for such operations as diffusion or ion implantation etching and so forth until the integrated circuits are completed.

2340

Ex. 5. Прочитайте и переведите текст А, обращая внимание на функции и перевод Participle I, II:

Words to be remembered

Ex. 6. Переведите следующие словосочетания:

to apply in conventional photography, to be sensitive to ultraviolet light, to become stable to etchants; selective exposure to light, to destroy polymer chain; to dry hard, desired circuit pattern; transferred image; to remove the oxide layer.

Ex.7 Найдите в тексте следующие словосочетания:

тонкая непрозрачная пленка; ультрафиолетовое излучение; полимеризует фоторезист, окна в слое окисла, ровная тонкая пленка, растворять незащищенные участки, плотно прижимать к поверхностному слою.

Grammar Revision

Ex. 8. Образуйте от следующих глаголов все формы причастий, дайте их перевод. Вспомните синтаксические функции причастий:

to apply; to use; to read; to compare; to reduce; to desire; to accumulate; to form; to move

Ex. 9. Прочитайте и переведите предложения, обращая внимание на функции причастия в предложении.

1. Microsystem electronics is a term defining work applicable towards achieving smaller electronic equipment.

2. Improved reliability by the introduction of circuit redundancy is possible only through reduced size of circuit components.

3. The emitter diffusion using a phosphorous compound is carried out with the oxide again masking all but desired region.

4. Coat reduction is to be a by-product of improved mechanized construction and assembly technique.

5. The diffusion technology was not only adapted to existing processes, it also led to new device structure.

6. Discussing the advantages of this new method, the lecture gave the audience all the necessary explanations.

7. Having made use of W. Mayer conclusions, Welker went further and attempted to predict the electrical properties of the III-Y components.

Ex. 10. Прочитайте и переведите предложения, обращая внимание на значения служебных слов:

1. Also as in macrocircuits, power must be expended to overcome the tolerance of all circuit components. 2. As long as we use this technique the cost will be very high. 3. As early as the beginning of the 50^th the subject of microminaturization became one of the “controversial” topics in the electronic field. 4. The 2 approaches necessarily complement each other as they are different means of describing the same physical phenomena. 5. Hence, completely new electronic function approaches chosen specifically for low-power operation will often be required. 6. Thus it has been possible to approach miniaturization in a functional manner. 7. Since all components exhibit a “spread” in values around their nominal ratings, the circuit designer never works with ideal components.

Ex. 11 Ответьте на вопросы к тексту А.

1. What is photolithography used for?

2. What are the main properties of photoresists?

3. What is a photomask?

4. How many steps does the photolithotechnique consist of?

What are they?

Ex. 12 Напишите аннотацию к тексту.

Ex. 13. Передайте основное содержание текста А.

Ex. 14 Прочитайте текст В и ответьте на вопросы:

а) Каковы недостатки фотолитографии?

б) Каковы новые направления развития фотолитографии?

1. Whatever the present significance of photolithography, it is not free from limitations. One of the principal limitations relates to resolution, which defines the fineness of detail in the produced pattern of the mask. The fact is that the wavelengths of ultraviolet light range between 0.2 and 0.3µm. However small the window in the photomask pattern, the size of its image in the photoresist cannot be as small as the values given above due to diffraction.

2. A most obvious approach to increasing resolution in lithography is to use short-wave radiations in exposure, for example, soft X-radiation with a wave-length of 1 or 2 nm. This approach is still in the stage of research.

3. However the use of short-wave radiation in itself cannot solve either the problem of decreasing the size of circuit elements or the problem of pattern alignment. What is needed here is a new technique for the fabrication of masks with submicronic pattern elements. Also, there is a need for new resists of increased resolution and appropriate chemicals for their treatment. Last, a basic problem that awaits its solution is to choose or develop an adequate source o X-radiation. One of the variants is a synchrotron, an installation applied in nuclear engineering. However this unique installation is too costly for use in industry on a large scale.

4. Even after bringing the above problems under control, it is out of the question to expect to have integrated elements with dimensions lying in the nanometer range. There are a number of factors which stand in the way of reaching this range, such as undercutting of a resist and silicon dioxide, lateral diffusion, or spreading of ions under the mask in ion implantation.

5. The trend aimed at decreasing the size of circuit elements, using in particular, x-radiation and electron beams has received the name “nanoelectronics” (submicronic technique).

6. One of the weak spots in classical photolithography is mechanical contact between the photomask and substrate coated with the photoresist. This contact cannot be too perfect, so it leads to various kinds of distortion of the pattern. The competing technique is projection photolithography in which the pattern on the photomask is projected on the substrate with the aid of a special optical system.

Ex. 15 Составьте 4-5 вопросов к тексту В, охватывающих основное содержание.

Ex.16 Придумайте заглавие к тексту В.

Ex. 17 Найдите в тексте В основные положения. Прочтите их вслух, соединяя различными средствами связи, приведенными ниже, таки образом, чтобы получился связанный текст, охватывающий основное содержание текста.

As far as, whatever, since, moreover, hence, thus, because of, due to, thanks to.

Характеристики

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