`
`l. A method of fabrricating.a
`microelectroflitdevice, eomprislng
`the
`furnishing a first substrate havIng
`fUrnishing afirst substrate· having
`anetchable layer/an etch:"st:op
`anetchable layer,ah etch;stop
`.Iaveroverlyi.-;gthe etchable layer,
`I~yer overlying the etchable J.;:jyer"
`anda WafefovetlyHlgthe etch;.stQP aru:fa wafer overlying the etch-stop
`.Iayer:;
`.layer;
`
`farmirlga m'icroel.ectronic Circuit
`ejementinthee~posed sJde.Qf the
`wafer of~thefirsts''''b$trate
`opp.osite. totne side overlYing the
`
`forming a microeJectronic circuit
`elementi)'j the expo,s¢cfsiQ'eof tf}e
`wafer(jfthefirst.sUb$t~ate;
`opposite thesideovedyirtgrthe
`
`furnishing a firstsubstrate hi;lvinga
`sfliecmetdhableJayerj a silitbn
`tiioxideetc:h-stop layer overlyJng
`the siUcot'llayer~and ~ single-crystal
`silicon wafer overlYing the etch
`stop. layer, the ,waferhavihg afront
`~urfa<=¢I1,({t.¢qnti:fqtrr'\g th¢>sn,con
`qiQxiQ~
`fdtmrl'lga microelectronic circuit
`e.1e:r;nel)t. i"the frC)i1t surf~ce of t~e
`$irigle-crystal sUir;onwafer;
`
`attachihgthe ""aferaf the first
`substrateto a seco:nd substrate;
`and
`
`attachil1gthe front suftaceofthe
`attaching the wafer of the first
`substrate toa secQndsubstratet the single'-cryStal siliconwafertoafirst
`side ofa second substrate; and
`second substrate having 'a second
`microelectronic circuit element
`
`making an electrical 'co ntact from
`the miCfoelectronictircuit element
`
`001
`
`
`SONY 1013
`
`
`
`in the wafer of the first substrate to
`the second microelectronic circuit
`element on the second substrate;
`and
`etching away the etchable layer of
`the first substrate down to the
`etch-stop layer; and
`
`
`forming an electrical connection to
`the microelectronic circuit element
`in the wafer of the first substrate
`through the etch-stop layer.
`
`etching away the etchable layer of
`the first substrate down to the
`etch-stop layer.
`
`
`
`
`
`
`etching away the silicon etchable
`layer down to the silicon dioxide
`etch-stop layer
`using an etchant that attacks the
`silicon layer but not the silicon
`dioxide layer.
`
`
`002