2834 Macromolecules, Vol. 43, No. 6, 2010
Mizoguchi et al.
Synthesis of Hex-1,6-ylenebis[oxy(3,5-dimethylbenzene)] (HOD).
To a solution of 3,5-dimethyllphenol (5.00 g, 40.9 mmol) and 1,6-
dibromohexane (4.65 g, 19.0 mmol) in DMF (35 mL) was added
potassium carbonate (8.53 g, 61.4 mmol).24 The mixture was
stirred at 80 °C for 18 h under nitrogen. The reaction mixture
was cooled to room temperature and poured into distilled water
(500 mL) to afford a light ocher solid. The solid was filtrated and
washed with water. The product was recrystallized from n-hexane
to give a white solid. Yield: 5.53 g (89%); mp 69.4-70.3 °C. IR
(KBr, ν, cm-1): 3014-2854 (CH3, -CH2-), 1589 (Ar), 1463,
1427, and 1390 (CH3, -CH2-), 1294 and 1076 (-O-) cm-1, 1H
NMR (CDCl3, δ, ppm): 1.50-1.55 (m, 4H, -CH2-), 1.75-1.85
(m, 4H, -CH2-), 2.28 (s, 12H, -CH3), 3.91-3.95 (t, 4H, -
CH2O-), 6.53 (s, 4H, Ar), 6.58 (s, 2H, Ar). Anal. Calcd for
C22H30O2: C, 80.94; H, 9.26. Found: C, 81.22; H, 9.18.
80 °C for 30 s on the hot plate. After that, these films were
exposed to 300 mJ/cm2 of i-line through the photomask and
followed by PEB on the hot plate at 160-200 °C for the set time.
Those films were developed by dipping in toluene at 25 °C. The
˚
dissolution rate (A/s) of the film was determined from both
developing time and changes in the film thickness before and
after the development.
Photosensitivity of PSPPE. The photosensitive polymer film
with 1.2 μm thickness on a silicon wafer was prepared by
dissolving PPE, HOAD, and DIAS in 1,1,2,2-tetrachloroethane
(total solid content: 6.5 wt %) at room temperature, followed by
spin-casting on a silicon wafer and prebaking at 80 °C for 30 s on
the hot plate, exposed to i-line irradiation with changing the
exposure dose, PEB at 190 °C for 5 min on the hot plate,
developed with dipping in toluene for 1 s at 25 °C. A character-
istic photosensitive curve was obtained by plotting a normalized
film thickness against exposure dose (unit: mJ/cm2). Image-wise
exposure through a photomask was carried out in a contact-
printing mode.
Synthesis of Hex-1,6-ylenebis[oxy(2,4,6-tris(chloromethylmethyl)-
3,5-dimethylbenzene)] (HOCD). To a solution of HOD (0.500 g,
1.53 mmol), chloromethyl methyl ether (2.22 g, 2.07 mL, 27.6 mmol)
in dehydrated CH2Cl2 (15 mL) was dropwised over 15 min a
solution of SnCl4 (7.19 g, 3.23 mL, 27.6 mmol) in dehydrated
CH2Cl2 (5 mL) under nitrogen in ice bath (0-5 °C).23 The reaction
mixture was stirred for 1 h in an ice bath and then at room
temperature for 7 h. After that, the unconverted SnCl4 was
quenched with distilled water (100 mL). The product was extracted
three times with CH2Cl2 and washed with water. The separated
organic layer was dried over magnesium sulfate, filtrated, and
concentrated in vacuo. The crude product was purified by column
chromatography with CH2Cl2, giving a white solid. Yield: 0.730 g
(77%); mp 198.8-199.5 °C. IR (KBr, ν, cm-1): 2921-2856 (CH3,
-CH2-), 1571 (Ar), 1452 and 1384 (CH3, -CH2-), 1255 and 1087
Preparation of Polymer Films for TGA, DSC, Water Absorp-
tion (WA), Dielectric Constant, and Residual Stress Measure-
ment. To prepare the thick cured PSPPE films for TGA, DSC,
and WA measurement, a negative-type PSPPE resist solution
(PPE/HOAD/DIAS = 83/10/7 wt %) in 1,1,2,2-tetrachloro-
ethane (total solid content: 18.6 wt %) was cast on a glass plate,
kept at that room temperature for 6 h, prebaked at 80 °C for 10
min on the hot plate in air, and then the film was irradiated with
i-line of 1000 mJ/cm2, followed by PEB at 190 °C for 1 h under a
flow of nitrogen, and finally cured at 220 °C for 1 h on the hot
plate under a flow of nitrogen.18 The thick PPE film as a
reference was prepared from 16.2 wt % 1,1,2,2-tetrachloro-
ethane solution and followed by similar thermal treatment of
the cured PSPPE film, without exposure. The cured PSPPE film
(the rectangle-shaped film: length 40 mm, width 35 mm, thick-
ness 45 μm) and the PPE film (the rectangle-shaped film: length
40 mm, width 35 mm, thickness 43 μm) were prepared for WA
measurement, and those films were used for TGA and DSC.
Whereas, to measure the refractive indices and optically esti-
mated dielectric constants of a cured PSPPE and PPE film, the
cured PSPPE film on a quartz substrate was prepared from a
similar PSPPE solution by solvent-casting and prebaking at
80 °C for 1 min in air, irradiation with i-line of 1000 mJ/cm2,
PEB at 190 °C for 10 min, and curing at 220 °C for 1 h on the hot
plate under a flow of nitrogen. As a reference, the PPE film was
prepared from 16.2 wt % 1,1,2,2-tetrachloroethane solution and
followed by similar thermal treatment for the cured PSPPE film,
without exposure. The thickness of the cured PSPPE and
PPE films were 4.8 and 4.2 μm, respectively. In the case of
direct measurement of dielectric constants and dissipation
factors, both the 10.4 μm thick PSPPE and the cured 9.8 μm
thick PPE film on each 50 mmꢀ50 mm square silicon wafer
(thickness: 712.5 μm) were prepared following the above-men-
tioned preparation condition for refractive index. Moreover, in
order to measure residual stress of each silicon wafer of the cured
PSPPE and PPE film, the cured PSPPE film on an 8 in. silicon
substrate (diameter: 200 mm; thickness: 712.5 μm) was prepared
from 10 wt % PSPPE solution in 1,1,2,2-tetrachloroethane, by
spin-casting, and prebaking at 80 °C for 30 s on the hot plate in
air, exposure with i-line of 300 mJ/cm2, PEB at 190 °C for 5 min,
and curing at 220 °C for 1 h in an oven under a flow of nitrogen.
And also, the PPE film on an 8 in. silicon wafer was prepared
from 10 wt % 1,1,2,2-tetrachloroethane solution and followed
by same thermal treatment for the cured PSPPE film, without
exposure. Those thickness of the cured PSPPE and PPE films on
each 8 in. silicon wafer were 3.2 and 3.1 μm, respectively.
Water Absorption. WA was measured by immersing the cured
PSPPE film and PPE film into the distilled water at 25 °C for
6 h.18 After that, those films (the cured PSPPE film: length
40 mm, width 35 mm, thickness 45 μm; PPE film: length 40 mm,
width 35 mm, thickness 43 μm) were taken out, wiped with tissue
1
cm-1 (-O-). H NMR (CDCl3, δ, ppm): 1.64-1.73 (m, 4H, -
CH2-), 1.94-2.03 (m, 4H, -CH2-), 2.51 (s, 12H, -CH3), 4.07-
4.10 (t, 4H, -OCHH2-), 4.68 (s, 4H, -CH2Cl), 4.74 (s, 8H, -
CH2Cl). Anal. Calcd for C28H36Cl6O2: C,54.48; H, 5.88. Found: C,
54.25; H, 5.76.
Synthesis of Hex-1,6-ylenebis[oxy(2,4,6-tris(acetyloxymethyl)-
3,5-dimethylbenzene)] (HOAD). A solution of HOCD (0.500 g,
0.810 mmol) and sodium acetate (0.81 g, 9.72 mmol) in AcOH
(35 mL) was refluxed for 33 h under nitrogen.22 The reaction
mixturewas cooledtoroomtemperatureandpouredintodistilled
water (300 mL) to afford HOAD as a white solid. The pro-
duct was recrystallized from ethyl acetate/n-hexane (7/11 volume
ratio) to give a white solid. Yield: 0.570 g (93%); mp 163.8-
164.5 °C. IR (KBr, ν, cm-1): 2931-2866 (CH3, -CH2-), 1736
(CdO), 1585 (Ar), 1442 and 1381 (CH3, -CH2-), 1246 and
1026 cm-1 (-O-). 1H NMR (CDCl3, δ, ppm): 1.51-1.55
(m, 4H, -CH2-), 1.80-1.89 (m, 4H, -CH2-), 2.07 (s, 12H, -
COCH3), 2.09 (s, 6H, -COCH3), 2.36 (s, 12H, -CH3), 3.76-
3.80 (t, 4H, -CH2O-), 5.22 (s, 12H, -CH2OCdO). 13C NMR
(CDCl3, δ, ppm): 16.10, 21.35, 26.37, 30.44, 59.55, 61.53, 126.1,
129.8, 142.0, 158.9, 171.3, 171.4, 171.6. Anal. Calcd for
C40H54O14: C, 63.31; H, 7.17. Found: C, 63.31; H, 7.10.
Acid-Catalyzed Model Cross-Linking Reaction. To PPE (45.0
mg, 0.375 mmol) and PBA (5.00 mg, 0.023 mmol) in deuterated
chloroform (0.6 mL, CDCl3) in a NMR glass tube was added
CH3SO3H (0.0005 g, 0.005 mmol: 1.3 mol % to PPE).18 Nitro-
gen was charged to the glass tube, and the tube was heated at
60 °C for 1 h. To investigate the behavior of self-polycondensa-
tion of a cross-linker HOAD, CH3SO3H (0.0005 g, 0.0052
mmol: 10 mol % to PBA) was added to a solution of PBA
(0.0113 g, 0.051 mmol) as a cross-linker model compound in
deuterated chloroform (0.6 mL, CDCl3) in the NMR glass tube.
The glass tube was heated at 60 °C for 30 min under nitrogen.
The 1H NMR of the each sample was measured at 25 °C.
Dissolution Rate. PPE, each cross-linker (HOAD: 7, 10, and
20 wt %, TAB, MBMP,18 CYMEL:25 10 wt %), and DIAS19,20
(5, 7, and 10 wt %) were dissolved in 1,1,2,2-tetrachloroethane
(solid content: 6.5 wt %) at room temperature. Their polymer
films (film thickness: ca. 1.2 μm) were obtained by spin-casting
from PSPPE varnish solution on a silicon wafer and prebaked at