1.
 Influence of Fluorination on Surface and Dielectric Characteristics of Polyimide Thin Film
  

        

^†   *

  

305-600    100

* 

136-709    5 1 (2003 1 15! "#, 2003 3 25! $%)

Influence of Fluorination on Surface and Dielectric Characteristics of Polyimide Thin Film

Soo-Jin Park^†, Ki-Sook Cho and Sung-Hyun Kim*

Advanced Materials Division, Korea Research Institute of Chemical Technology, 100 Jang-dong, Yuseong-gu, Daejeon 305-600, Korea

*Department of Chemical Engineering, Korea University, 1, 5-ka, Anam-dong, Sungbuk-gu, Seoul 136-709, Korea (Received 15 January 2003; accepted 25 March 2003)



            X-ray photoelectron spectroscopy (XPS)    !" #$%&, '(·)*( + thermogravimetric analysis (TGA) ,-./0   &

 5 AB  C%1. D6 45 EFG 7   HIJ (electron polarization) C

KL&, M  NO@ ," HNO0 =7KP>@Q      CKR ST6 ,H@ UV6 W

>@ XYG1. Z6
23     '(·)*(  M [\ E] ^+ W #$_ ` ab1.

Abstract−In this work, the effects of fluorine treatment of polyimide thin film on surface and dielectric characteristics were studied using X-ray photoelectron spectroscopy (XPS) and dielectric constant, respectively. And, their thermal and mechanical properties of the polyimide film were characterized by thermogravimetric analysis (TGA) and tensile strength, respectively.

The fluorine content of the polyimide film was increased with increasing the amount of the treatment gas, resulting in decreas- ing the dielectric constant of the film. It was explained that the replacement of fluorine led to the decrease of the local electron polarization of polyimide, or to the increase of the free volume which can be attributed to the relatively large volume of flu- orine. Nevertheless, the fluorination didn’t significantly affect thermal or mechanical properties of the polyimide film under a mild condition in this system.

Key words: Polyimide, Fluorination, Dielectric Constant, Thermal Properties, Mechanical Properties

1.  

       

-O-, -NH-, -CO-     !" #, $% &

300^oC' ()*  +,- ./0 12 345 67 &

12 89:; /< = >?@ =[1-2]. A  B

 CDE
 9!·9 F  GH, I, JK, L*

MF NO, PQRF NO, STU  F =.

EA VWFX) YZ [ \] .^$/  L*M

& 9 VW2 N '  !_`a b c d- ef ag

h   ILD (interlayer dielectric) B# i !_' `a j

k/ =. ILD B# ) 89l mn 8 op,  q r) st/' uN, vp, :t stw (cross-talk) /, xp, stw / ry*' z. C q$/NP$ . , {p, NP$ q$ .|}u & ~  ' ! : . , c

 =€p, 9!·9 F GH Q‚   ƒ„ r;

h  0 3…† r & y* J‡- h   ˆ‰Š

& ‹Œ!!, sŽ, 'Ž, ‘’ ‹F 9 Ž  F . 8=[3-4].

“L 89l” 89M, • Q*M' 9!C d- –—

 mn d ˜ ™N š›œ   ž@ Ÿ

+−moment2 bQ)  ¡ 9 "' ¢£Œ$ ¤¥ ¦§

(polarization)¨=. ©ª bQ 9 "' Œ$ «w B# Q'

†To whom correspondence should be addressed.

E-mail: psjin@krict.re.kr

 41 4 2003 8

+− moment. ¦§ ,*; 89l¬ ­®h  =[5]. A 89l- UD nC2 op, N$*' Œ$, vp, 8Q¯

(free volume)' Œ$, xp, ¦§' ,* (polarizability); [  =

[6]. A ° !CDE ±Z ILDB# šN; ²8³´

 ' µ2 ¦§5 ¶ 8Q¯ Cw 12 89:; ·

 }B# i . j ¸ / =. df 12 89 l,  ¹!" # Cw ILD B#)
;  F šNº» i . j k ¼=[7-9].

šN†  =½ † ¾ ¢DE ¸= ¶ 9 ¿$*¾ ($

potential- ./ 0, .Ž À2 9! Á*; ./  =½

$ÂB5' LÃ Ä ÅD=. “L šNÆ! D) B#

- Çh È N†  šN¾ º»DÉ  m–

conjugated bond šN 'w) Ê$¨=. A šN =½ †N

¾ ÂDE  a, Ë Ì},  9! d, ST,  ' d- –— Í Î2 X) F/ =[10-12].

Ϭ) Ð ) šN$ Ç '
 GH' ­Ñd

5 c Ͻ 89l' Œ$; iÒDÓ=[13-14]. Ð °Ô) Â

¨
ÕÖV' $ ,*; Fourier Transform-IR (FT-IR);  w iÒDÓ0, šN$ Ç ' GH' ­Ñ & 89d- XPS

¾ 89l ×,- w ØCDÓ=. Ù ·!" d2 TGA¾ CŽÅ* ×,- DE ÒDÓ=.

2.  

2-1.
  

Ð °Ô F¨ dianhydride (3,3',4,4'-benzophenonetetracarboxylic dianhydride; D BTDA)¾ diamine (4,4'-oxydianiline; DODA)2

Aldrich) ÚV ÛÜM; ݒÞ$ß ,U; DE FDÓ=.

FÄ Aldrich' N-methyl-1-pyrrolidinone (NMP, anhydrous quality);

FDÓ0, ÛÜM & FÄ' $% à- Fig. 1 –—á=.

' šN$ ­ÑÇ Žº UµDE FDÓ0 šN

F₂ .â; FDÓ=.

' 9MC
ÕÖV(polyamic acid; PAA) FI- Â

D! Æw 3 ã¬âä; #N purging å, NMP diamine- æ

 ç' dianhydride; è9f æE 24³éê+ Lóë ÂDÓ

=. ¨
ÕÖV FI' M#Ül2 15 wt% }DÓ=.

¨
ÕÖV FI- substrate F¨ 8ì Æ applicator (Sheen Instrument, S220403); FDE í± îK' ïð. 50µm

*ñ òâó å FÄ; za³ô! Æw 80^oC) 24³é ê+

prebakingDÓ=. Fig. 2 –—õ (*Û"
ÕÖV- ö$³ë í±
 îK- U DÓ0, ö$ Û"÷ $%à- Fig. 3

 –—á=.

U¨
 GH ­Ñ „S šN$ ÇD! 9


 GH- øùú ^) ûÁü ýþ!; Fw ýþ å GH' ÿ E- U
D! Æw ) Dk: ³ë) FDÓ=.

 GH- šN$ ­ÑÇD! Æw ‡ #N.â fluorination reactor line- purging å < boat GH-  reaction tube <

 boat; ŽTDÓ=. < boat; - ³ reaction tube [. V N¾ - U
D! Æw =³ #N.â purging =Á reaction line- r9ݒ 10⁻² torr / J!³=. GH- ­ÑÇD!

Æw reaction line šN.â; 0 kPa(D F0), 5 kPa(F5), 10 kPa(F10), 30 kPa(F30), 50 kPa(F50)  ‹ DE šN .âÜ- }DÓ

0, :() 10 ê+ Ló å r9ݒ  >k–

- 5³ë 10⁻² torr / J!³=.

Fig. 1. Chemical structures of dianydride, dianiline, and solvent.

Fig. 2. Heating cycles for thermal imidization of polyamic acid.

Fig. 3. Preparation of polyimide via polyamic acid precuror solution.

2-2.  

Ð °Ô) Â
' $ ,*; ØCD! Æw

ÕÖV FI5 ö$¨
 GH- KRS-5 reflection element . QT¨ Digilab FTS-165 spectrometer; Fw) wave number 4,000-400 cm⁻¹' FT-IR â DÓ=.

2-3. 

U¨ GH- šN$ Ç Ͻ
 GH' $% 2 XPS (ESCALAB MK-II); DE DÓ0, XPS ×, F¨

X-ray source Mg Kα; FDÓ0, chamber' 2 10⁻¹-10⁻⁹ torr }DÓ=.

2-4.    

 GH' šN$ Ç 9·å' 89(*' Œ$ DSC (Dupont 9,900: model 2,910); FDE Þ(^* 10^oC/min :(

) 400^oC / ×,DÓ0,  d' Œ$ #NÆ! D) Þ(^* 10^oC/min :() 800^oC / TGA (Dupont 9,900:

model 2,950); FDE ×,DÓ=.

šN$ Ç Ͻ
 CŽÅ*  O ³Ô!(Universal Testing Machine, Lloyd LR5K); FDE ASTM D412 DE ³

¦- UµDÓ0, cross head speed 50 mm/min ×,DÓ=. × ,˜2 ' ³¦ «DE 10r ×,DE c ™˜- FDÓ=.

2-5.  

Ð °Ô) šN$ Ç 9·å'
 GH' 89l Œ$;

×,D! Æw Dielectric Spectrometer (Novocontrol GmbH, Model:

CONCEPT 40)- FDE ×,DÓ=. 89l ×, 2 :()

‹ü; 10¹ HzQŠ âò à 10⁶ Hz / Œ$³ôÑ) 89 l- ×,DÓ=.

3.  

3-1.  

Fig. 4
' $ ,*; ØCD! Æw
ÕÖV5

ö$’,-
 U¨
 GH' FT-IR spectra 5=. “ L
KV' $ ³ =Á5 2 ï Û"' ’,-

¿=. op, ï ÛÜM; FÄ æÑ BTDA' . Ñ) ODA

¾ `»m LÃ “–
ÕÖV FI- ÂDÉ ¨=. vp, `

»m 'w Ú¨ B .  'w za, ï ÛÜM .¢

; k
'  $. ± Ý=[15].

A 5,QŠ
ÕÖV FI' FT-IR spectra; –— Fig. 4(a)

; iÒDÑ, c) ¸ ¾  `»LÃ '
ÕÖV F I' d ¯äC  !³V' O-H (3,400-2,400 cm⁻¹)¾ Õ"' N-H (3,500-3,100 cm⁻¹); ØCh  0, dianydride' C=O (1,660, 1,535 cm⁻¹)¾ C6H₅' C=C (1,513 cm⁻¹) ' ¯ä. –—õ #- ØCh  á=[6, 16].

LÑ
ÕÖV FI- 80^oC) 24³éê+ FÄ; za³ô

prebaking ’,-
¿ å 50^oC) 290^oC / Û"÷ ö$’,-

¿
 GH' FT-IR spectra; Fig. 4(b) –—á=. Ð °Ô

5,
ÕÖV) –—õ O-H (3,400-2,400 cm⁻¹)¾ N-H (3,500- 3,100 cm⁻¹). $ÂLÃ 'w B ; Ú³ô  'w 

$. Ý%Ñ) ¯ä. ¬Ý #- ØCh  á0, A 5,

 Cw Ú¨   (725 cm⁻¹); iÒh  á=. Ù ,

' 9PC d¯äC C=O (1,780, 1,720 cm⁻¹), C-N (1,370 cm⁻¹) c (OC)2NC (1,100 cm⁻¹) ' ¯ä. Ú¨ #- iÒh 

á0[6, 16], A 5QŠ $. 100% Ý%áÁ- Ø Ch  á=.

3-2. 

šN$ Ç9·å'
 ­Ñ' i ! - ýf &'¸

! ÆDE
 GH' XPS spectra; Fig. 5 –—á=. c

5 Ç
' ö Â(/ 285 eVQY) ùN ¯ä,

404 eVQY) #N¯ä c 532 eVQY) VN ¯ä. –—õ

#- ØCh  á=. LÑ šN$ Ç ö 694 eV QY) š N ¯ä. )*É –—+0, šNÇ .â z.hñ, • Ç

 .âÜ z.hñ
' šN ¯äý!. z.D #- iÒh  á=. A
' $%- Table 1 –—

5, šN$ Ç 'w
' ùN, #N, VN' ²Ü2 Ç

.â  Ϭ uND LÑ, šN' ²Ü2 z.D #- ØC

Fig. 4. FT-IR spectra of polyamic acid and cured polyimide thin film.

Fig. 5. XPS survey scan spectra of polyimide thin film.

Table 1. Chemical composition of polyimide thin film

C_1S N_1S O_1S F_1S F_1S/C_1S

F00 F50 F10 F30 F50

69.7 55.0 56.0 49.5 49.1

10.30 8.0 5.7 4.6 4.7

20.0 24.0 21.7 16.0 13.0

0 13.0 16.6 29.9 33.2

0 23.6 29.6 60.4 67.6

 41 4 2003 8

h  á=.

“L šN†  =½ † ¸= ¶ 9 ¿$*¾ ($

potential- ./ 0, .Ž À2 9! Á*; ./ ,

=½ $ÂB5' LÃ Ä ÅD=. df F2.â LÃ -) .^- ʲ «Q' $ÂB5 LÃD0, df ùN$ÂB5 Ía

 LÃD0 LÃ- aÚ³=. 5* LÃ aÚÑ (*

:Þ Cw C-C Â w
– \ äÉ  = >?@ 

=[10-12]. •, šNÆ! D) B#- ­ÑÇDÑ B# ­Ñ' š +, Â // LÃ À2 ¬01 Ú šN¾ º

»DÉ 0, m– conjugated bond šN 'w) Ê$ ¨

= >?@ =[12]. cA,
 GH ­Ñ šN; ²8 µF!; 2 \ :ýf D! Æw) XPS carbon 1S core level

scan spectra ' !#- ¢ DE Fig. 6 –—á=.

Ð °Ô5, šN$ ÇD/ 32
 GHC Fig. 6(a)' ö

284.6 eV (C=C), 285.6 eV (C-N), 286.2 eV (C-O-C) c 289.2 eV

(C=C))
' 9PC d¯ä; ØCh  á=. šN

$ Ç ö
' šNº» 'w Fig. 6(b)¾ (c)) )

*É 288.7 eV (C-F)¾ 291.1 eV (CF2)' ¯ä. Ú¨ #- ØCh   á0, Ù Fig. 6(d)¾ (e)' ö 288.7 eV¾ 291.1 eVb 290.5 eV (CF₂ in trifulorobenzene)) ¯ä. Ú¨ #- iÒh  á=.  A 5 F2.â; FDE
 GH- šN$ Ç ³ :

!) 45 šN' Là ø-<65 
¾ šN† ' LÃ C-F Ù CF2Â
 º»¨ #- ØCh 

á=. Ù Fig. 6(d)¾ (e)) 7  ª šN.â  30 kPa

:C ö
 º»¨ šN²Ü äÉ z.DE C=C

¯ä¸= C-F ¯ä. \ äÉ a8D 5; –—á0 È' F_1S/C_1S. Table 1) ØCh  ª  60.4%¾ 67.6% =

½ GH' ö w ¶ ˜- –— #- iÒh  á=.

3-3.    

šN$ Ç Ͻ
' DSC9‡- Fig. 7 –—á=.

c 5, Ç
' Tg (glass transition temperature). 283.6^oC Fig. 6. High resolution C_1S XPS spectra of polyimide thin film with fluori-

nation concentration; (a) F0 (b) F5, (c) F10, (d) F30, and (e) F50.

Table 2. Mechanical properties of polyimide thin film

Tensile strength [MPa] Ultimate elongation [%]

F00 F50 F10 F30 F50

116±10.7 115±13.5 115±11.0 118±14.5 118±12.3

33±4.3 34±3.1 32±2.9 38±4.5 37±3.2

–—+0 šN$ Ç ö F50' Tg. 282.7^oC uN 5;

ØCh  á=. “L T_g :- º C )  Ü, ’ mÂM, ,$*, $% ,   0, A C [' Œ

$ Cw  ' 8Q¯. z.DÑ c : 'w Tg. uN = >?@ =[17]. :! XPS 5) Ò ¾ ,


 º»¨ šN† ' Q¯. N– ùN¸= ä! È;  ' 8Q¯; z.³´ Fig. 7) –—õ ¾  Tg. u N # ìÛ¨=.

Fig. 82
' TGA9‡- –— 5=. A TGA9

‡QŠ Table 3 IDT (initial decomposition temperature); –—

á=. c 5, F0' ö IDT. 555^oC –—+0 šN$ Ç

ö F5¾ F10' ö ¶ …; –—/ 3<– F30' ö =N uNDÓ0 F50' ö û! w `³ (*. äÉ uN #- ØCh  á=. “L
    

   -O-, -NH-, -CO-     !"

 # & 300^oC' ()*  +,- –—= >?@ =

[1-2]. cA– 5Ü' šN¾ LÃ Cw :! šNLà ø-<6

) 45DÓª
'     =/Ñ) F50 ' º»¨ C-F ¯ä. äÉ z.  Cw û! w (*. ä É uN # ìÛ¨=[6, 16, 18]. cA– F50- Ub =½


' ö, šN$ Ç ³ šN²Ü 30% D º»¨


 šNÇ 'w  +, ¶ :- º/ 3/ šN² Ü 30% :C
' ö  +, =N uN #- i Òh  á=.

šN$ Ç 9·å'
 GH' CŽÅ*(tensile strength)¾ üÛ sl(ultimate elongation)- Table 2 –—á=. Ð °Ô5  Ç
C F0' CŽÅ* 116 MPa, üÛ sl2 33%

–—á0, šN$ Ç
 GH' ö Ç GH'

˜5 ¢DE ¶ Œ$; –—/ 32 #- ØCh  á=. A 5 „S šN$ Ç 'w
 * ¨ šN.


' !" B ¶ :- º/ 32 # ìÛ¨=

[6, 9, 19].

3-4.  

89d2 (* & ‹ü Ϭ c J' ±£ & ®: 8¬Ý

= >?@ =[5]. Ð °Ô) šNÇ 9·å
' 89 l- :() ‹ü; 10¹ HzQŠ 10⁶ Hz / Œ$³ôÑ) ×,D Ó0 c 5; Fig. 8 –—á=. Ð °Ô5, Ç


C F0' ö 89l ‹ü>Æ Ϭ 3.1-2.9' Ê; ¸ Ó0 ×, ™˜ 3.04 9PC
' ˜- –—á

=[13-14]. cA– šN$ Ç GH' ö :! ­Ñi ! 5

) Ò ¾  Ç.â  z.DE * ¨ šN²Ü z .hñ 5 GH' 89l uND ö- iÒh   á=. •, ×,¨ ‹ü >Æ) 89l ™˜ F5=2.99, F10=2.68, F30=2.67 c F50=2.55 ®Ëf uN #- ØCh  á=.

:! )?) 45 ¾  89l2 N$*, 8Q¯, ¦§

' ý ./ nC äÉ :- @0 N$*¾ ¦§5 A D0 8Q¯¾ LA =[6, 8-9]. Ð °Ô) GH „S šN

$ Ç; ² * ¨ šN Cw
    8Q¯ z.D ¦§2 uNDE 5 89l uN #

 ìÛ¨=. A 8 op, DSC5) Ò ¾  š N$ Ç 'w
 º»¨ šN† .
' 

  8Q¯; z.³ë 89l uN # iÒ¨=[20].

vp, 9 . B) C D@    9 . B ÅDÉ E

   ¸= \ FÉ ¦§D, 9 [ B G ÛÛDÉ E

 šN† ' ¦§2 µ=. Ù , ù$šN 2  Ü- . Fig. 7. DSC diagrams of polyimide thin film.

Fig. 8. TGA thermograms of polyimide thin film.

Table 3. Thermal stability parameter of polyimide thin film

F0 F5 F10 F30 F50

IDT [^oC] 555 549 550 533 395

Fig. 9. Dielectric constants of polyimide thin film.

 41 4 2003 8

Ý ù$N¾ ¢h È Ä Hb IJ 10 A  8 K) 45 « šN†  Ä 12 ¦§ È; van der

Waals C Ջ µÕ/! È;=. cA, C-F Â' 9 ¦§

 C-H  ¢DE ¸= µ! È; šN$ Ç


' 89l uN # ìÛ¨=[20].

4.  

Ð ) ILD (interlayer dielectric) B# L F


' 89l- uN³ô! Æw šN$ ÇDE GH' ­Ñd

& 89d- iÒDÓ=. Ð °Ô5 šN$ Ç 'w =Á5  2 5; iÒ h  á=.

(1) U¨
 GH Æ šN$ Ç; DÓ0, °Ô5 Ç.â  z.hñ, • Ç .âÜ z.hñ GH * ¨ šN²Ü z. #- ØCh  á=.

(2)
' ·!" d' ö šNÇ. GH' B

äÉ :- º/ 32 #- iÒh  á=. LÑ F50' ö IDT . =½ ³¦ w äÉ uNDÓ–, û! w `³ (*. F30 / 530^oC :)   d- –— #- ØCh 

á=.

(3) šN$ ÇDE
 GH * ¨ šN†  Cw  ' ¦§- uN³ô 8Q¯; z.³ë 5 8 9l uN #- iÒh  á=.

 

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