游戏规则

1.找一个一定时间内可以完成的目标，确定要完成的事情和具体的完成时间 2.每天强制自己花费一定时间去完成目标 3.完成目标的过程中，留下一些阶段性的标志(也是可以是当前的最近进度，体会感悟等等) 4.完成时间截至时，检查目标的完成程度。 5.如果完成，制定新的目标玩下一关；   如果失败，要有一定的惩罚，并在当前基础上，迭代开始再一次游戏。

 2007年11月14日23时
初定目标，Introduction to Microlithography,共493页，打算一天看30页，17天看完。
由于下周二有考试，决定下周二才开始执行。
先写下目标，以防忘记。

11月20日22：40时
今天没看！

19.12.2007,21:22
Ich habe das Buch nicht gelesen.Schade!Entschuldigung!
Ich weiß nicht,was ich seit 21.11.2007 gemacht habe.
Was kann ich tun?
Irgendwie,ich muss mich strafen,deshalb  wird ich  mich von drei Tagen keine  Chance geben,falsche Wörter  zu sagen.Es ist wirklich sehr schwierig,weil ich oft mehre Fehler mache,wenn ich mit andere rede.

20.12.2007,00:10
I have read only five pages.Alas.
I read very slowly,as it seems to be difficult for me to understand or maybe  because I did not concentrate on it when reading.
It is something about some problems existing in X-lithography and some requirements of x-lithography mask fabrication.

24.12.2007,0:30
Another five pages.
1.Resolution in x-ray lithography is determined by the fate of the photoelectron that is generated by absorption of an x-ray photon in the resist.The larger the photon energy is,the longer the range of photoelectrons,and the better the resolution.
2.the next requirement of an x-ray lithography is a bright x-ray source.
(1)Power  output of the sources based on electron bombardment is not high enough.
(2)Alternative sources are hot plasma and synchrotrons.
1)A hot plasma source works on the principle of rapidly heating a plasma (laser-produced).
2)Synchrotron depends on changing the direction of relativistic electrons such that the emitted radiation in the range of 1nm.
The beam is highly collimated so that t eliminates the penumbral effects associated with electron-impact sources.Likewise,control of the mask-wafer gap is not critical.Consequently,resolution is primarily limited by Fresnel diffraction effects and the range of the ejected photo-Auger electrons.
(3)X-ray projection lithography with soft X-rays.
1)The system consists of a multilayer-coated,Schwarzschild,x-ray reduction optic projecting a 5x-redued image of an X-ray reflecting mask onto a resist-coated wafer.This specific design requires normal incidence spherical mirrors and a reflecting X-ray mask formed b patterning normal-incidence,soft X-ray multilayer mirrors.
2)Projection X-ray lithography offers several advantages over proximity printing:the ability to demagnify the image means that 1:1 replication is no longer required,and the need for a submicrometer mask technology with its attendant diffiulties is eliminated;a reflecting mask would be more robust nd have higher contrast than a transmission mask.
3)Challenges: the design and fabrication of masks and precision optical elements,alighment,system metrology,and feedback control.

25.12.2007 2:42
ANOTHER FIVE PAGES.
SOMETHING ABOUT RESIST:
REQUIREMENTS,HIERARCHY.
TWO-COMPONENT RESIST IS BEING READ.

26.12.2007 2:39
Resist Sensitometry
1)response to light
photoefficicency: for diazonaphythoquinone used in positive photoresist it is from 0.2 to 0.3,for that used in negative photoresists it ranges from 0.5 to 1.0.For hotoresensitive polymers used in one-component positive resists it is difficult to determine experimentally,but for PMIPK it is 0.3 at 313nm (for vinylketone polymers a solution one is higher than one in the glassy state).
2)Response to ionizing radiation
molecular weight:it decreases monotonically with increasing dose.
Tomorrow I will find out the reason for the introduction to it and its meanings.

27.12.2007 1:46
149-153
1.The line of the inverse of mocular weight versus dose can be used to get te intrinsic radiation sensitivity,which is determined by the slope of line.Pay attention to the correction factor.
2.Lithographi sensitivity
It is difficult to measure,as it depends on many parameters.The choice of method must depend upon the goals and will require careful interpretation.
1)Positive resist sensitometry
The laser end-point detection system is used to get data for the curve which can provide information about the sensitivity,or dose response.The principle of the system is interference.
Tomorrow I will find out what is the meaning of those curves.

28.12.2007 2:20
154-159
1)The curve of the thickness remaining versus log dose:the lower is Ds(defined by man),the higher is the sensitivity; the larger is the slope,the higher is the contrast.
2)The experiment measuring the curve:for negative resist,under optical exposure,the resists should be exposed hrough the substrate from the back side,to obtain meaningful data.
3)The value Ds is of little value unless accompanied by a definition of  Ds and detaild description of the conditions under which it was measured,including at the minimum,the initial film tickness;the charateristics of the substrate;the temperature and time of the post- and prebake;the characteristics of the exposing radiation;an the developer compositon,time,and temperature;the structure,copolymer ratio,sequence distribution,molecular weight,and dispersity of polymers include in the formulation.It is discussed in greater detail in Chapter 4,which I will cover tomorrow.

29.12.2007 2:32
Chapter 4
1)five stages involved in the ivention and implementation of new and viable resist systems:
a.fundamental researh on new polymer and radiation chemistr
b.synhesis and characterization of potential materials
c.lithographic evaluation of formulations
d.engineering scaleup of the synthesis of a specific,identified material
e.process development for manufacturing application
2)The sensitivity and contrast of a resist are primarily determined by the properties of the polymer and the processing parameters.
The polymer properties include
chemical composition,molecular weight,molecular weight distribution,glass transition temperature(Tg),density,quantum efficiency,average atomic number(for X-ray,eletron-beam,and ion-beam methods),optical density.
The processing parameters include
developing criteria,developing conditions,developer composition,pre- and postbaking conditions,postexposure bake(chemically amplified resists),processing environment (chemically amplified resists).
Tomorrow I will find out what is molecular weight distribution and its meaning.

29.12.2007 16:36
E-beam resists(also something about molecular weight,but still not its distribution)
1)PMMA offers high resolution,ease of handling,excellent film-forming characteristics,wide processing latitude,and ready availability,but it is insensitive and a less efficient plasma or RIE mask.
Terpolymer resist clearlyy demonstrates a significant improement in sensitivity over PMMA.
2)Styrene resists
a)Polystyrene is seakly sensitive,negative electron resist,but perturbations in the structure have a profound effect on its radiation chemistry,e.g.improve its sensitivity.
b)Reducing dispersity at constant number-average moecular weight results in increased contrast to some limit that is structure dependent;
increased molecular weigtht at constant disersity results in increased sensitivity
c)Swelling distortes images.It is difficult to avoid.
(1)during the development process,the cross-linked areaabsorbs a large volume of solvent and must increase its dimensions,which causes image distortion.
(2)another common manifestation of the swelling is the formation of snake-ike distortions of long,narrow images.
Details of swelling will be covered tomorrow.