Goodard v. Google, Inc.

Filing 157

Goodard v. Google, Inc.

Doc. 157 Att. 1

EXHIBIT B

Dockets.Justia.com

tes
Jang et al.

I9 11

[ill
1451
[561

Patent Number: Date of Patent:
Refewow Ctd ie

5,740,
Apr, 14, 1998

[541 METHOD FOR MANUPACTUWNG SEMICONDUCTOR DEVICE 1 5 Inventors: Young-Cbol Jang, Suwon; Hyo-!jeok 71 ehoi. Seoul; Domg-Heui Jang; Sun-YongLee. both of Suwon, all of Rep. of Korea [73] Assignee: Smunsoog E2ech.onic.s Co., Ltd., Suwon. Rep. of Korea PI] Appl. No.: 449p3
p2] Filed:

4,627,010 4,780,617 4,910,679 4,958,160 5,243,377

us. PIYmNT DOCUMENTS 1Z1986 Kosogi .................................. lor1988 Umatate et at. ........................ 31990 Takahashi e ai. ...................... t 9/1990 It0 et al. ................................... t 9f1993 Umatate e al. ..........................

364,559 250/548 3W490 35553 355f53

M[ay24,1995

Assistunt hminer-PhaUaka Kik Artomex Agent, or Flmt--cUshman D&y & Cushman Group of piusbury Madison & Sutro JLP

Primary Examiner-Kevin J. Teska

IP

P1 O

Foreign Appticatiw priority Data May2.5, 1994 1 Rep. o f K o m .................. 11408/1994

17 51

mRAcT

HBlL 21/68; WlB 1V26; GO6P 17/18 34 6 / 3644491;3641551.01: W 1 2 US. C1. .......... 51 364/554; 3641575;364i468.15;3641468.21; 364146828; 43718;355153 I581 Fjdd of %SIX% "............3641552. 468, 3641490. 559.488.491. 578, 571.01-571.05, 551.01-555,468.01..468.28, 575;2501548, 491.2492.22; 355153.43;3561401;43W30; 437/8

[Sl] h L 0 ........................... :

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A method for manufacturing a semiconduaor device compriscs the steps of extracting an optimal working condition by acmnulatiwly averaging aawmulated working conditions of lots preriously performed in an expectation proccss to be currently p e r f d in the manufaduring equipment. extracting a correction condition by extracting infomation for an alignment state of a lower layer performed by the expectation process. and setting the working condition by adding the correction condition to the Optimat working condition.
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METHOD FOR MANUFACTURING

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working condition is incorredy set due to measurement e r r o ~ mistake by an individual worker. the defect is or SEMICONDUCTOR DEVICE generated in the wafcs of the whole lot manufactured by the BACKGROUND OF THE INVEhTION same serial process. Theseby. the wnpling process may be s again performed or the whole lot may be afccted. 1. Field of the Invention Ftlrtficrmorc, if the result of the sampling process is Tbe present invention relates to a method for manufacarbieafiY checked and estimaM by the Worker or if Me turing a semicondudor device, and more particularly to a performance ofthe SamPbg F m S S is not confirmedOwing manufacturing method capable of automatically setting a to a worker's mistake or negiect. it is diffiatlt to insure the warldng condition in a manufacauiog process prfomed by 1 repreducibility of the process. thereby lowering the reliabil0 lots. ity of its products. 2. Description of the Related Art
It is therefore object of the present invention to provide a metfiod for manufacturing a semiconductor device which integrating semiconductex elements on the semiconductor can directly perfam a fabrication process without requiring substrate by repeating a tf&i Nm forming process, B photoresist layer paam forming process and an etching proa -ling process. FWher. *en Performing *e above P r O C ~ ~ a unit SIt is the other object of the present invention to provide a Pwess is @om& with wenty-frve sheets of wafers to 20 mehod famanufaatning a scmioonductor device capable fQ sheets O wafer constituting a unit lot. The photoresist f of w o e g ~ ~ reducing the prwess i ~ by ~ , , rime layer pattan forming process and the etching process. for -,,fachning produds, among the unit perfcsmed by lot, are It is another object of the present invention to provide a sensitive to variations i a working condition. M e r , the n in which method for manufacftninga semicondudor pwsses include a s m h g process for a lot swle.re&bjjiq is excellent h a u s e of &e improvements in 25 Le.. one o two sheets of wafers, before starting the process r reproductionof me process. for the whole l t According to a result of the sampling o. It is a mr objeet of the present invention to provide a e process. aprwss v&&le is reset before pesformingad process for the whole lot. Such a method is widely used in for manufadrninga semiconductor device capb1e of improving productivity by reducing working time of manufacturing semiconductor devices. In the following description of prior art processes inciud- 30 manufacturing equipment required for a sampling process. kg tfie prmss, for convenience sake, the The present invention having the above objects comprises the Steps Of c m h g an 0~working condition by photossist layer pattern f d g process will e x p a d mn a p r e s s d j e d for one lot is n w i v d one a e a c m h t i v e l y averaEing accumulated working conditions sheets of sample wafers from among the received process 35 Of Ids pr&OuS1y pehfwmed in an vss to be performed in the mnufactud"g equipment* are sei&&.. m e selected sample wafers undeago a photoresist hyer-ting process. a wafer &gnmeot & extracting a correction condition by extrading information state Of a 'OWer layer pafonned by the exposure process, and a development prmss to thereby for complete the sampling process. According to the result of eXpeCQtiOQPf-S. and S e a g the working condition by &e alignmat sate adding the correction condition to the optimal working the s q b g process, Le., -checking of a pattern and measurinn a Critical Dimension ICD). the optiia~ working conditionlis extracted. ~urther. proCess thk BRIEP DEScRIpfION OF THEi DEtAWINGS variables axe reset to be suitable for the extracted condition and the photoresist layer pattcm forming process for the "be above and other objects. advantages and features of whole lot i s pcrformcd by the seE warkiog mndition. Such 45 the F m n t invention will be more apparent from t e folh a samplingprocess is widely used for etdIiag prcxesses such lowing W e d descriptiontaken With the attached &wings as Chemical Vapor Deposition (CVD). as well as in photo in which: P e s = . For a w e . in &e etching proce~s* or two one showing the order of a photoresist FIG. 1 is a flow sheets of wafers s e l e e d as a and etched to layer pattern forming process acwrding to the present thereby check whether or not an etching condition is appro- 50 invention; w a k by insan etching profile, m s a g the tuckRG, 2 is a Mock diagram of an alignment & exposure ness of a remaining layer. or measuring the CD.Lo accorl a Y e r ~ a e r n formingprocess Of d&= with &e &e& res&. the pr-s variables (etching the wesent invention; time, etching activation energy. and so on) adjusted and the F G 3 a f o chart showing the control I. lw main process is thus performed. ss aligoment is expsure forperformingan order of an 8r device However. with tfie sampling process desabove, expswe according to the wsent Pwss invention;and there arise the faowing problem, First, due to the time for FIG. 4 is a flow chart showing a data required for the sampIing process, the o v e a process time restJk a wo*g condition. requirement time must be increased. thereby inueasing a 7brn Around T m e CTpLT) for a produd to be finally corn- 60 D E T W DESCRZPIlON OF THE pleted through each layer forming and photoetching process. PREFERWD EMBODIME%T Additionally. when the sampling process must be again performed due to defects genmated therein. the above webRG. 1 i s a flow chart showing the mder of a photoresistor iern becomes even mare serious. layer pattern fuming process according to an embodiment Moreover, the accuracy of the pe&immce of the sam- 6s ofthe present invention. Referring to FIG. 1, when the l d for which the process is to be performed is inputted. a photopling process and the reset of the working condition depend resist layer coating process 101 for all wafers in the lor is upon how well a worker handles the equipment. I the f

In general. when a number of semiconductor devices arc serially manufactured on a semiconductor substrate, e.g., a silicon wafer. there generally is perfamed a process o f

SUMMARY OF THE " I O N

emtion

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w o r m e d in a photoresist layer spread &vice. Afta the of the current process is obtained by adding to the error a utpid photoresist layer coating process, an alignment & exposure value m l i l e by a gain determined according to the amount of correlation between each layer. process 102for the whole lot is performed for each wafer in the a&unent & exposure device. At Mis point. as mentioned below, a working condition is set by a p r o w stored 5 ML*W (2) in the alignment & exposure device during the alignment & exposureprocess according to the present invention,thereby In the above equation (2). the alignment parameter Axy' permitting the alignment C exposure process for the whole of the current process is determined by adding the alignment lot to be performed without a samphg process. After utpid par?lmeterAxy to a mlile value (ExG). The gain has the: completion of the alignment 8 exposure process, a process 10 value of 0.W1.00and indicates the correlation between the c 103 for developing the photoresist layer exposed by the reference layer and the layer expected to be aurently alignment & expostae process is performed and the photopesformed resist layer p a is thus formed on the wafer. After the Aftex the parameter values aceording to the alignment C completion of the development process, a process 104 for exposure process are determhed depending upon the above r checking whethex o not the photoresist layer patte.rn i s 15 equations (1) and (2). the values axe inputted to the aligofomed as intended. is @armed. purther,after the comple ment & exposure device and used as the optimal conditions tion of alf the above processes. a working condition res6 of the alignment & exposure process to be currently peaprocess 1 6 i s performed to apply changes to the working formed condition of the alignment & exposure device. The working FIG. 2 is a block diagram View of the alignment & condition reset process is peaonned through a correspond- 20 exposure device used in the photoresist layer pattep forming set of parameter values. At this time, the parameters to f ing process o the present invention. Refening to FIG. 2. the be set are elements such as exposure time, focus offset. alignment & exposure device comprises a host computer 1 0 spatial shifts X and Y. X-Y scaling. wafer rotation. for controlling opexation of each part, an exposure part 12 cathogonality, and s on, Le., the elements affecting the o for paforming the alignment & exposure opcration by the 25 loading of the wafer. a wafer transmission control part 14 for alignment 8c exposure process of the wafer. controlling the transmission and alignment of the wafer in The catculation of an optimal value fof each parameter is the alignment h exposure device. and a driving control part performed as follows. 16 for controlling the operation acccrrding to exposure of the 1) The production of a parameter value related to an exposure pari 1 . The host coinputex 1O has a mntral 2 exposure condition 30 processing unit CPU 1 for controlling the operation of each 8 The optimai condition of parameter values necessary for part, a keyboard 1 for inputting a control command and 9 exposure are obtained by adding together the parameters for various kinds of data to the CPU 18,a memory 20 for staring lots within a standard deviation of flq67.58)from a progmms to control the B U 18 and also storing the data reference value set in advance after prccessing previous lots inputted from the B U 1 . and a m n t r 2 for displaying 8 oio 1 using the previous same process, thereby setting the optimal 3s data outputted from the CPU IS. condition of the current proctss. The parameter value of the FIG. 3 is a f o chart showing a control order of the lw ament process is determined by the following equation (If. alignment & exposure device for performing the alignment & exposure process according to the present invtation. En

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alignment In the photoresist layer pattern forming process. the alignment operation is perfomed on the basis of an alignment key formed in a lower layer or a reference layer during the manufacuuing process of the semiconductos device. 60 Further. since an alignment state o the alignment key in the f process previously performed afFects that of the current process. the error for the existing alignment state should be used in the alignment of the current process. Accordingly, it is necessary to add the error to the parametex in accordance 6s with the wafer alignment of the current process. That is. as seen in the following equation (2). an alignment parameta

correction data. However, if the conection data is not inputted from the keyboard 19 in step 111 above, the B U 18 pedforrns a step 113 of detecting whether (H not a signal is inputfed from the keyboard 1 . the signal informing that 9 there is no need to perform the m c d o n operation. I the f Informatioo signal is [e-mail] CPU 18reads the woiidng condition stored in the memory and p c x f m a step 114 of setting the read working condition as that of the alignment & exposure process to be amently performed.Thereafter. the CPU 1 controls the exposure part l .the wafer trans8 2 6 mission control part 14, and the driving control part 1 according to the working condition set in the above step 112

What is daimed is: 1. A method for manufactuting a semiconductor device with manufadushg equipment perfonniag a process having a working condition. said manufaduring equipment being 5 adapted to manufachne said semiconductor device i units n Of M S . said xuethod CO@Sbg the Steps Of: ment & exposure process for the object lot is completed extracting an optimal working condition by accumulaAccording to the resuit of the detection. if the process is tively avenging working conditions of lots previously completed. the CPU 18 finishes the operation by controlling processed using said process performed by said manuthe opention of each part to thereby enter an operation 1 0 faaufing equipment; mode. extrading a correction condition by extracting informaAs mentioned above wt reference to E[G. 1. when the ih tion corresponding to rn alignment state of said process; alignment & exposure operation for the whole lot is compIeted in the alignment & exposure &vice through the above setting a m e n t working condition by adding said corsteps. the process in step 104 of detecting whether the rection condition to said optimal working condition; photoresist layer pattern is formed according to a predeterand mined setting condition after the develqpment proccss. is performing said process fot an entire lot accwding to said performed After completing & W o n process. a step 1% of cuxrent waking condition. Storing data in the memory 20%through the &Ward 1 .for 9 2.Amethod for manufacturing a semiconductordevice as example. is performed in the alignment & exposure device. claimed in claim 1.whtdein said working condition incIudes *e used for xseaing the w m b g condition Of the process parameter values. and wherein said stcp of extractnext process. ing said optimal working condition incIudes respectively FIG,4 is a flow chart showing a step of inputting data for a v e n g each of said p w s s p m e t e r values of said resetting the w d g condition. With respect to FIG. 4, a 25 working conditions of said previously processed lots. step of resetting the working condition in the alignment & 3. A~iethodfo~ manufacturing a semiconductordevice as cLaimed claim 2, further comprising a step of detecting a exposure device shown in EG. 2 is as follows. If a control signal to indicate a working condition reset mode is inputted resultant value of performing said process accmding to said through the keyboard. the CPU 18peaforms a step of storing current workkg condition, and each parameter value inputted through the keyboard 1 in xi wherein said step o extracting said cptimal working 9 f condition includes acaunulativefy averaging working the corresponding area of the memory 20. (Le. an area in which the parameters of processes previously perfoxmtd arc conditions set for selected ones of said previously stored). At this time. the input p""neter values are of the processed lots. each having a cmrespooding resultant exposure process. Further, the input parameter values value differing from a reference value by no more than include reald t values having errors generatedaccordingto 35 aa a standard deviation. 4. A method according to dah 1. wherein said working the result of the exposure process and the data for correcting the emr. I?urthermos. the input parameter values may have condition indudcs process parameter vaiues and alignment parameter values and wherein said step of setting said the already completed correction. The 8 U 18 reads the V&OUS kinds of parameter values stored in the memory 20 cwent working condition includes adding said cci-rection to thereby perform a step 117 of producing the optimal value 4o condition to said alignment parameta values of said optimal for each pametex from the read value. Thereby. an opcimal working condition. parameter value i obtained from the parameters of the s 5 A method according to claim 4. wherein said process is . a photoresist alignment and exposure pfcpcess, and whaein processes previously performed as well as the process just performed. the optimal value being used in the next process. said process parametex values include at least one of an Thereafter. the CPU 18 sets a new working condition 45 exposure time. a focus offset. an X-Yspatial shift, an X-Y acoording to the optimal value for each parameter produced scaling. a wafer rotation. and an ortfiogonality facta. in step 117 above t thcxeby perfom a step of staring the o 6. A method according to claim 1. whctein said step of new working condition in the conesponding area of the extracting said comctioa condition includes multiplying a Correction value by a gain whose value is determined memory 20, Le., h area in which the previous working condition is stoxd. by over-writing the set working condi- 5o acconlng to an amount of cornlation between lots. tion. After the completion of the storage step, the CPU 18 7.A method according to daim 1. further comprising the steps of: finishes a l l the operations and enters the cperation standby mode. detecting a resuitant value of pa-foming said process according to said w e n t working condition; and When the parameters are added for processing using the same equipment, it is possible to set more precise optimal 55 resetting said current working condition in accordance pameters. Thereby, it is also possible to minimize mors with said resultant value. generated in the alignment & exposun process. 8. A method for manufacturing a semiconductor device AS discussed in the foregoing description. in the present with m&a-g equipment performing a p r o ~ having ~s invention, the correction for errors generated in previous a W a h Z condition. said mmufa-g equipment being a new working 60 adapted to manufacture said semiconductor device in units processes is taken into account to thus condition in the interior thereof. Thereby. it is possible to of IOts, said method C O m k 3 the Steps Of: manufacture semiconductor devices using only a main proeXnaUhg an optimal Working condition by accumulacess without the need for a sampling process. Therefore. the tively averaging working conditions of lots previously processed using said process performed by said manumanufacturing method according to the present invention improves reliability for producf reliability as well as pro- 65 fag qU&mnt; ih setting a current working condition based on said o p W ductivity in accordance wt the reduction of production time. working condition:

or 114 to thereby have a step 115 of serially performing the alignment & exposure operation with respect to wafm in the whole lot. "he control qmation of each part through the CPU 18 after the determination of the working condition is the m e as that of the prior sh stqr 115 the mu 18 perfom a step 116 of detecting whether or not the align-

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current working condition; detecting a Of performing said process according to said ament working condition; and resening said current working condition in accordance with said resultant value. 9. A method according to claim 8. futher cornpising a step of extracting a correction condition by extracting inforI-nafionc=spon&g to atigDmcnt state of said Process. 10.A mcthod aceording to d a h 9. wherein said Working condition includes process parameter values and alignment parameter values and wherein said step of sea& said w e n t working condition includes adding said correction
@arming saidpmms for an entire lot according to said

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condition to said alignment parameter values of said optimal working condition. 1 . A method according to claim 8, wherein said working 1 condi&,n hcfu&s prmss parameter values. and said step of said optimat condition indudes respectively averaging each of said process parameter vaiues of said current working conditions set for said pwioudY wssed lots* 12. A m t o aceofdiog to claim 8. wherein said step of ehd extracfing said optimai working condition includes Bccumuf&ively wdg . for *led& ones an&tioas & of said previously prms%d lots for which said resultant value is witfiin a standard &viation.

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