CVD_Process_Introduction

1、cvd process introductionoutline1. cvd process introduction2. cvd type classification3. dielectric film characteristic4. cvd film application-darc and lowk5. q & a2outline1. cvd process introduction2. cvd type classification3. dielectric film characteristic4. cvd film application-darc and lowk5.

2、q & a31. cvd process introduction4cvd(chemical vapor deposition) :the process of depositing solid films using gases or vapors via chemical reaction on the substrate surface.advantages of cvd :good step coverage can be achieved wide range of materials availablegood composition controlgood process

3、 control1. cvd process introduction5the sequence of reaction steps in a cvd reactiondiffusion of reaction to surfacediffusion of products from surfacefilm-forming reactionsubsequent surface reactiondesorptionabsorption1. transport of reacting gaseous species to the substrate surface2. the reactants

4、are adsorbed on the substrate.3. the adatoms undergo migration and film-forming chemical reactions.4. desorption of gaseous reaction by-products5.transport of reaction by-products away from the substrate surface cvd process sequenceprecursorsarriveonthesurfacemigrateonthesurfacereactonthesurfacenucl

5、eation:islandformationislandsgrowislandsgrow(crosssection)islandsmergecontinuousthinfilm1. cvd process introduction(i):mass transport limited at higher temperature deposition rate is sensitive to flux concentration insensitive to temperature (ii):surface reaction rate limited at lower temperature de

6、position rate is sensitive to temperature insensitive to flux concentration (i)(ii)1. cvd process introductiondep rate vs tempschematic diagrams of transport of reacting gaseous species from source to the substrate surface for (a) surface reaction rate limited reaction, and (b) mass transport limite

7、d reaction.1. cvd process introductionsurface reaction & mass transport limitedcomponents of dcvd systems1. gas sources2. gas feed lines3. mass flow controller4. reaction chamber5. heating and temperature control system6. pumping and pressure control system7. rf system 8. exhaust1. cvd process i

8、ntroduction1. cvd process introduction10n-wellp-wellp+p+n+n+apl(aluminum pad layer)rv (re-distribution via)m1m2m3m4t4m2via1via2via3t4v2imd 2imd 3imd 4imd 5imd 1pmdcb (chip barrier)stiimd(inter metal dielectric) sin/sicn/sicsio2/fsg/siochpassivation:sio2 sinsionbeolfeolsti (shallow trench isolation)p

9、oly hm (hard mask)spacersab (salicide block)smt (stress memory technology)cesl (contact etch stop layer)pmd (pre-metal dielectric)1. cvd process introduction11dcvd process precursors:silicon source: teos,sih4, tmsoxygen source: o3 ,teos,n2o,o2phosphorus source: tepo,ph3boron source: teb,b2h6fluorine

10、: sif4, nf3nitric source: n2,nh3carbon source: c2h2, c3h6tms: (ch3)4si, 四甲基硅烷四甲基硅烷, tetramethylsilaneteos: si(oc2h5)4, 四乙氧基硅烷四乙氧基硅烷, tetraethoxysilane tepo: po(oc2h5)3, 三乙氧基磷烷三乙氧基磷烷, triethyl phosphateteb: b(oc2h5)3, 三乙氧基硼烷三乙氧基硼烷, triethyl boratesio2 (usg), sin, sion, psg, bpsg, sicn, sioc, fsg outl

11、ine1. cvd process introduction2. cvd type classification3. dielectric film characteristic4. cvd film application-darc and lowk5. q & a122. cvd types classification13temperature based hto & lto (high & low temperature oxide) rtcvd (rapid thermal cvd)pressure based lpcvd (low pressure) apc

12、vd (atmospheric pressure) sacvd (sub atmospheric pressure)reagent based silane teos mocvd (metal organic)energy based thermal cvd pecvd (plasma enhanced) hdp (high density plasma)2. cvd types classification14processproconlpcvdexcellent purity, uniform conformal, large wafer capacityhigh temperature,

13、 low dep ratepecvdlow temperature, high dep ratehydrogen content, poor step coveragesacvdlow temperature, conformallow dep rate, moisture uptake, surface sensitivityhdpcvdexcellent gap fill, high quality oxidecomplex reactorpro & con for some typical cvd processthree popular methods are widely a

14、dopted to produce sio2.1. lpcvd teos oxide (typical spacer oxide)si(oc2h5)4 - sio2 + by-products d.r.: 55 a/min. 700c2. pecvd teos oxide (typical imd oxide)si(oc2h5)4 + o2 - sio2 + by-products d.r.: 7000 a/min. plasma (400c)3. sacvd o3/teos oxide (typical imd oxide)si(oc2h5)4 + o3 - sio2 + by-produc

15、ts d.r.: 1800 a/min. 400c2. cvd types classificationheating vs plasma1. lpcvd si3n4 depositionnh3 + sih2cl2 - si3n4 + by products d.r.: 18 a/min. 740c 780c2. pecvd si3n4 deposition .(2)sih4 + nh3 + n2 - sixnyhz + by products d.r.: 9000 a/min. 400c2. cvd types classificationpecvd nit2. cvd types clas

16、sification17plasmasheater platerf powerprocess gasesbyproduct to the pumpwaferprocess chambershower headsacvd:no rf system, no plasmasimple sketch map for pecvd & sacvd process2. cvd types classification18basic principle of hdp cvd2. cvd types classification19oversputteringsputteringofmetalandar

17、clayeratthecornertoolittlesputteringcuspingofdepositionoxide-poorgap-fillingresultsinvoidequilibrium between deposition and sputtering at the cornerdeposition rate (dc) = sputtering rate (sc) maximized gapfill capability2. cvd types classification20pecvdhdp cvdgapfill capability compareoutline1. cvd

18、 process introduction2. cvd type classification3. dielectric film characteristic4. cvd film application-darc and lowk5. q & a213. dielectric film characteristic221. particle2. thickness & uniformity3. refractive index - impurity, composition - density4. reflectivity5. stress6. ftir - composi

19、tion bonding ratio: si-f, si-h, si-n, si-ch3 - impurity (-h, -oh, h2o)7, xrf -dopant concentration: b, p8. etching rate - composition (dopant level) - density9.sem & tem - step coverage/ gap fill - degree of planarization10.electrical properties - dielectric constant - dielectric breakdown3. die

20、lectric film characteristic23non-uniformityrange-uniformityuniformity3. dielectric film characteristic24dep rate, shrinkagetimedepthicknessdepratedep.cyclethermalbeforethicknesscyclethermalafterthicknesscyclethermalbeforethicknessshrinkage after a thermal cycle, film thickness shrinks. the smaller t

21、he shrinkage, the better the film quality. deposition rate is a very important specification of a cvd process, as it is directly related to throughput.3. dielectric film characteristic25ri can deliver the information for films chemical composition and physical condition.ri (refractive index)3. diele

22、ctric film characteristic26stress3. dielectric film characteristic27rttefsfilm1162beforeafterrrr111r is the calculated radius of curvaturets is the substrate thicknesstf is the film thicknesse is the substrate yongs modulusv is the substrate poisson ratiog. gerald stoney. proc. r. soc. lond. a80. 17

23、2-175 (1909)stress3. dielectric film characteristic28step coverageteossilaneoutline1. cvd process introduction2. cvd type classification3. dielectric film characteristic4. cvd film application-darc and lowk5. q & a294. cvd film application-darc30darc (dielectric anti reflective coating)314. cvd

24、film application-darc324. cvd film application-darcwhy need low k? rc delay4. cvd film application-low k33how to do low k? porosity air is considered the perfect insulator. it has a dielectric constant of 1. one method of creating low-k dielectric materials is to introduce nanometer scale pores into a solid film to lower its effective dielectric constant.4. cvd film application-low k3435typetypeeqp ideqp idtool modeltool modelappli