A method of bonding substrates together via a bond layer precursor coating formed from a silicon base polymeric material, wherein said bond layer precursor coating is free of particles having a particle size of at least 1 μm and able to cure at a temperature of up to 400°C into a cured film having a modulus of elasticity of up to 4 GPa, said cured film experiencing a weight loss of up to 3% when heated at 400°C and held at 400°C for 60 minutes, wherein the modulus of elasticity is measured by the nano-indentation technique, and measurement of the weight loss is performed by using a TG/DTA (thermogravimetry/differential thermal analysis) system, wherein a volume of the bonding composition is dropped in an aluminum pan so that a film having an appropriate thickness of about 1 μm is formed, heating the aluminum pan on a hot plate at 100 to 200 °C for evaporating off the excess solvent, mounting the pan in the system, where the sample is heated at a ramp of 10 °C/sec to 400 °C and held at 400 °C for 1 minute, after which the heater is shut off and the weight of the nonvolatile remaining in the pan is measured, heating again the sample at 400 °C and held at the temperature for one hour, measuring the weight of the sample, and determining the weight loss, and wherein the modulus of elasticity is determined by a method of applying the bonding composition onto a suitable substrate to form a coating, heating the coating at a temperature sufficient to facilitate curing, thus obtaining a cured film, and measuring the modulus of elasticity of the film by applying the bonding composition onto a silicon wafer to form a precursor coating, heating the coating at 100 to 200°C for about one minute to evaporate off the excess solvent remaining in the coating, placing the coating in a firing furnace and heating in a nitrogen atmosphere at 350°C for 60 minutes whereby the precursor coating is heat cured, the cured film becoming a sample, wherein the modulus of elasticity of this sample is measured by the nano-indentation technique, wherein said bond layer precursor coating is formed of a high-temperature bonding composition comprising a silicon base polymer as a thermosetting binder, wherein said silicon base polymer is obtained from dehydrolytic condensation of a condensate precursor or a mixture thereof, said condensate precursor comprising a silane compound having at least one pair of silicon atoms tied by a crosslink composed of an optionally cyclic structure-containing straight or branched aliphatic hydrocarbon group of 1 to 10 carbon atoms, or a cyclic aliphatic hydrocarbon group of 1 to 10 carbon atoms, a heterocycle-containing group of 4 or 8 carbon atoms, or an aromatic ring-containing hydrocarbon group of 6 to 12 carbon atoms, the silane compound having at least three hydroxyl groups and/or hydrolyzable groups, and those silicon atoms having a direct bond to the crosslink composed of the aliphatic hydrocarbon group, the heterocycle-containing group or the aromatic ring-containing hydrocarbon group are present in a proportion of at least 90 mol% relative to all silicon atoms in said silicon base polymer, and wherein those silicon atoms having a direct bond to the crosslink composed of the aliphatic hydrocarbon group, the heterocycle-containing group or the aromatic ring-containing hydrocarbon group in said silicon base polymer have the structure of the general formula: Q p SiR 4-p-q X q wherein p is an integer of 1 to 4, q is an integer of 0 to 2, 2 ≤ p+q ≤ 4, Q is each independently a di- to pentavalent crosslinking group composed of the aliphatic hydrocarbon group, the heterocycle-containing group or the aromatic ring-containing hydrocarbon group, X is each independently hydrogen, hydroxyl, alkoxy of 1 to 4 carbon atoms, or a bond to an oxygen atom bonding with another silicon atom, and R is an optionally substituted, aliphatic or aromatic ring-containing monovalent hydrocarbon group of 1 to 12 carbon atoms, wherein the number of silicon atoms satisfying p+q ≥ 3 in formula is at least 70 mol% of the total number of silicon atoms included in formula.