TOKYO OHKA KOGYO CO., LTD. (TOK) provides chemical products, such as photoresist, and equipment for semiconductors and displays.

HOME Products New Business Field Materials Varnish for high heat resistance and high transparency polyimide film

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Under the “Challenge for the Future!” slogan, TOK has set up the New Business Development Dept. combined sales and technical division.
TOK offers unique and high value-added materials ,using our functional polymer design/manufacturing technologies cultivated in photolithography field, through open innovation with our customers and third parties.

Varnish for high heat resistance and high transparency polyimide film

Varnish for high heat resistance and high transparency polyimide film. Provided in the form of polyamic acid.

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  • High heat resistance   : Glass transition temperature (Tg) is 430 ℃ or higher.
  • High transparency   : Visible light transmittance is 90% or more (film thickness 10 μm).
  • High dimensional stability : The residual stress value of the film after curing is 1.0 MPa or less.
  • Excellent chemical resistance   :  Inactive against various organic solvents, acids and alkalis.

Applications

  • Various display-related fields

・Substrate for smart glasses
・Substrate for transparent display

  • Other semiconductor-related fields

・Transparent circuit board

Heat resistance

High heat resistance compared to general transparent resin film.

tga
tma

Transmittance

High transparency compared to conventional  polyimide.

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Residual stress

Low residual stress and high dimensional stability, as a transparent polyimide film.

Chemical-resistance

Resistance to various organic solvents and acids / alkalis.

SolventChemical Resistance Results

Immersion

Condition

*1 Etchant〇 (No change)40 ℃ - 30 min
*2 Stripper 10640 ℃ - 30 min
NMP (1-methyl-2-pyrrolidone)23 ℃ - 30 min
*3 TMAH 2.38% aq.23 ℃ - 30 min
*1 Nitric acid / Phosphoric acid / Acetic acid = 20% / 55% / 5%
*2 Mono ethanol amine / Dimethyl sulfoxide = 70% / 30%
*3 Tetra methyl ammonium hydroxide
〇:No Film change,  ✕:Film Change

Low metal content

Low metal grade utilizing our high purification technology.

Metal contents Varnish (ppb)
NaKCaFePbSnZnCuCoNiMnCrAlMgBaLi
< 10

Characteristic of varnish

GradeSolvent Solid content
(wt%)
Viscosity
(mPa・s@25℃)
HTR-002*4 TMU / NMP15~18500~2,500
*4 Tetramethyl urea

Properties of film

Film propertiesHTR-002Measuring Method
Film thickness (μm、 After Cure)10Dektak
Thermal Properties

CTE

 (ppm/℃)

100 - 350 ℃9.0~11.0ISO 11359
100 - 430 ℃9.0~11.0
Tg (℃)> 435ISO 11359
Td 1.0% (℃)480~500ISO 11359

Mechanical

Properties

Tensile Stress (MPa)230ISO 527
Elongation (%)15~20ISO 527
Modulus(GPa)4.5ISO 527
Film Stress (MPa)±0.1-
Optical PropertiesTransmittance (%)400 nm75ISO 14782

Ave.

(380-780, nm)

90
Y.I. (D65)3.0~4.5ISO 17223
Haze(%)0.1ISO 14782
Rth (nm)1200-
Refractive index (589 nm)1.65-

Each property value in the table is a representative value and not a guaranteed value.

Film making process

  • Transparency is ensured by curing in a nitrogen atmosphere (O2 concentration : < 10 ppm).
  • Coating → *5 VCD → Prebake → Curing
*5 Vacuume Dry process
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Slit coater

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Inert oven

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HOME Products New Business Field Materials Varnish for high heat resistance and high transparency polyimide film