摘要:
Water absorption resistant polyimide/epoxy-based compositions, like pastes (or solutions), are particularly useful to make electronic screen-printable materials and electronic components. A group of hydrophobic epoxies (and soluble polyimides) was discovered to be particularly resistant to moisture absorption. The polyimide/epoxy pastes made with these epoxies (and these polyimides) may optionally contain thermal crosslinking agents, adhesion promoting agents, blocked isocyanates, and other inorganic fillers. The polyimide/epoxy pastes of the present invention can have a glass transition temperature greater than 250° C., a water absorption factor of less than 2%, and a positive solubility measurement.
摘要:
The low modulus polyimide adhesive compositions of the present invention contain a low modulus polyimidosiloxane polymer, a thermosetting substantially-non-halogenated epoxy (optionally including an epoxy catalyst), a plasticizer, an insoluble halogen-free flame-retardant filler, and optionally an adhesion promoter. The adhesive can be applied upon (or incorporated into) flexible circuits using a relatively low lamination temperature, generally no higher than 200, 190, 180, 175, 170, 165, 160, 155, or 150° C. The adhesive is generally resistant to unwanted curl even in cases where the adhesive polyimide and the base film polyimide have a coefficient of linear thermal expansions (measured between 50° C. and 250° C.) that differ by more than 10, 15, 20 25, or 30 ppm/° C.
摘要:
The invention relates to low-temperature curable photosensitive compositions containing a polyamic acid, which compositions are developable in aqueous alkaline solutions and are curable, at a temperature of at least 160° C. and up to 200° C., to low modulus polyimides suitable for use in electronic circuitry applications, and which are particularly suitable for use in flexible circuit applications where low curl, low temperature curing, and good adhesion is a significant advantage.
摘要:
The invention relates to low-temperature curable photosensitive compositions containing a polyamic acid, which compositions are developable in aqueous alkaline solutions and are curable, at a temperature of at least 160° C. and up to 200° C., to low modulus polyimides suitable for use in electronic circuitry applications, and which are particularly suitable for use in flexible circuit applications where low curl, low temperature curing, and good adhesion is a significant advantage.
摘要:
A composition comprising: a polymer with a glass transition temperature greater than 250° C. and a water absorption of 2% or less; one or more metals or metal compounds; and an organic solvent. The polymer can optionally include sites that can crosslink with one or more crosslinking agents. The compositions can be used to produce electronic components such as resistors, discrete or planar capacitors, conductive adhesives and electrical and thermal conductors. The invention is also directed to a composition comprising a polymer with a glass transition temperature greater than 250° C. and a water absorption of 2% or less, and an organic solvent. These compositions can also be used in a number of electronic applications such as an encapsulant and as an integrated circuit packaging material.
摘要:
Compositions comprising: an epoxy containing cyclic olefin resin with a water absorption of 2% or less; one or more phenolic resins with water absorption of less than 2% or less; an epoxy catalyst; optionally one or more of an electrically insulated filler, a defoamer and a colorant and one or more organic solvents. The compositions are useful as encapsulants and have a cure temperature of 190° C. or less.
摘要:
A photosensitive resin composition comprising a pre-imidized aromatic polyimide, which when coated on a silicon wafer, has a light transmittance at a wavelength of 365 nm of at least 1% and imparts low residual stress after cure. The composition can be patterned through I-line exposure followed by development with organic or alkaline solutions, and can be cured at relatively mild temperature to yield low-stress polyimide patterns. Electronic components having the polyimide patterns have high reliability.
摘要:
An organic encapsulant composition applied to formed-on-foil ceramic capacitors and embedded inside printed wiring boards allows the capacitor to resist printed wiring board chemicals and pass 1000 hours of accelerated life testing conducted under high humidity, elevated temperature and applied DC bias.
摘要:
Water absorption resistant polyimide pastes (or solutions), are particularly useful to make electronic screen printable pastes and the electronic components made from these pastes. A group of soluble polyimides and their solvents were discovered to be particularly resistant to moisture absorption. These polyimide solutions optionally contain polyimides also containing cross-linkable monomers and/or thermal cross-linking agents. In addition, these polyimide pastes may optionally contain adhesion promoting agents, blocked isocyanates, metals, metal oxides, and other inorganic fillers. The polyimide pastes (or solutions) of the present invention have a polyimide with a glass transition temperature greater than 250° C., have a water absorption factor of less than 2%, and a have a positive solubility measurement.
摘要:
The present invention is directed to coverlay compositions derived from two-layer polyamic acid-based composites having a cover layer and adjacent thereto an adhesive layer wherein the cover layer comprises polyamic acid and other additives allowing the composition to be photosensitive and aqueous base developable, and where the adhesive layer can form a polyimide having a glass transition temperature between 170 and 250° C. The two-layer coverlay compositions of the present invention are used to encapsulate metal circuit traces formed on a flexible printed circuit base substrate. These two-layer compositions are particularity useful due to having an overall in-plane CTE between 10 and 40 ppm/° C. a range that is useful in avoiding unwanted curling of a flexible printed circuit when used as a polyimide-based coverlay material.