SU915297A1 - Method of treating substrate from polyamide film - Google Patents

Description

The invention relates to methods for manufacturing microelectronic equipment and can be used for thermal stabilization of substrates of polyamide films.

Known methods of processing a dielectric substrate in various environments, using mechanical and ultrasonic excitation of the medium [1].

These methods include the operations of degreasing the modification of the substrate surface, i.e. modification of the latter, which consists in saturating it with adhesive functional groups.

Usually they are used in the treatment of solid substrates of sapphire, polycore, and glass, where the problem of heat-setting does not practically arise.

Closest to the proposed technical solution is the method of processing the surface of the substrate of polyimide, including the operations of degreasing and modification of the substrate, ie

2

enhancing the adhesiveness of its surface with respect to metallic coatings (2].

However, this method of surface preparation, used in preparing the substrate before gluing metal foil, does not stabilize the geometric dimensions of the polyimide base.

The purpose of the invention is to increase the stabilization of the geometric dimensions of the substrate without reducing its mechanical properties and adhesive ability.

This goal is achieved by the fact that according to the method of processing a substrate of polyimide film, including degreasing and surface modification of the substrate, before modifying the surface of the substrate, it is placed on a base of glass, after which heat treatment is carried out in an iner / foot gas at 105-115 ° C "Increase it to 270-290 C with speed

915297

0.5 t3 deg / min, incubated for 2-2.5 hours and cooled to room temperature.

Depending on the influence of the environment, polyimides can either be lengthened or shrink. In order to carry out irreversible and maximum shrinkage of the film, it is necessary to choose an air medium, but in order not to cause thermal decomposition of the surface of the layers, it is better to use inert gases (argon). It is also important in what state the substrate is, fixed or free. Typically, the substrate extending heat treatment in a fixed state, have such defects as "corrugations", "warpage", resulting from elongation and contraction of the free surface, excellent shrinkage and elongation fixed portion of the substrate. These defects lead pri- ₀ to that the transfer of the image from the photomask to the substrate in the manufacture of switching by the method of photolithography becomes impossible due to the backlight. Changes in geometrical parameters are closely related to the structure of the substrates of polyimide films approx.

Polyimides have an amorphous-crystalline structure. Their supramolecular ₃₀ structure in the oriented state is complex, but it plays a decisive role in the processes of thermal stabilization of polymers. As the radical changes in the annealing process, it determines the quality of thermal stabilization of the polymer. During annealing of substrates of polymers in a fixed (isometric) I state, reversible changes occur in them, i.e. with repeated heating of the film, it will again change the overall dimensions at various stages of the manufacture of boards. In the case of free annealing of oriented polymers, a significant

ten

15

35

40

up to 40-80? from the original length resizing. These measurements are irreversible. If the changes also occur at the beginning of the manufacturing process for the boards, then they will not already occur in the manufacturing process itself.

As the base on which the polyimide substrate is placed

- films in the process of heat treatment, choose such materials that have high quality surface treatment, thermal conductivity and heat capacity, close in value to the data of the processed material and the minimum coefficient of linear expansion. All the above requirements are met by glass (tab. *. 1). One of the main factors is also the sequence of heat treatment and other technological operations in the manufacture of boards.

Temperature-time mode is chosen based on the following prerequisites: for polyimide, which has a surface partial softening temperature within 270-290 ^p C. Measurements of mechanical properties of polyimides during heat treatment, as well as the accuracy of combining the substrate and photomask or incompatibility during the formation of switching and research methods thermo-differential analysis and electron microscopy confirmed the presence of optimal structuring, removal of the anisotropy of the geometrical dimensions of the disappearance of the macron arresters, when processing ^a substrate at 270-290 C, and 22.5 hours of exposure in an inert atmosphere based on the glass, followed by cooling to room temperature (Table. 2). Table 1

Type of material Thermal conductivity kcal / mh T heat capacity of CRA, cal / g. hail 10 ~ ⁶ , deg "^ Glass 0.5 0.21 0.5 The film is poly- imide 0.42 0.26

5 915297 6

Table 2

Pattern Compatibility % Temperature thermostabilisation, ° С %> 'Ger, kg / mm ² along across Along ι ! across 10-15 350 * 10 0,300 0.240 10.6 10.2 ± 15-2 200 + 10 0.324 0,220 10.8 10.00 0 280110 0,290 0,295 10.5 10.45

Example r. Degrease the substrate from a polyimide film by wiping with a tampon moistened with alcohol. Oven type IC 2 is filled with argon and heated to 110®S placed substrate ²⁰ from poly- imide film on a glass substrate devices intended for heat-treating the film. Heat the oven at a rate of 3 deg / min to ²⁸⁰ C and maintained for 2 hours after which the furnace ²⁵ is switched off and cooled to room temperature. Substrate shift in a desiccator.

Check for the presence of internal stresses by double refraction. ³⁰ Annealing causes irreversible changes, they contribute to the stabilization of the geometric parameters of the film, as evidenced by the disappearance of macrostresses and averaging of the mechanical characteristics of the film in the fractional and transverse directions.

The yield of boards increases to 100% at the stage of combining with photolithography. Compared with the base <0 object-method of chemical modification of the substrate, a preliminary calculation of the savings is 6 rubles. for 1 fee.

Claims (1)

Claim The method of processing the substrate of the polyimide film, including degreasing and modification of the substrate surface, characterized in that, in order to improve the stabilization of the geometric parameters of the substrate without reducing its mechanical properties and adhesiveness, before modifying the substrate surface it is placed on the base of glass, after which heat treatment is performed in a furnace in an inert gas atmosphere at 105-115 0 ^, to increase its 270-290®S at 0.5 ^_ 3 ° C / min, kept 2-2.5 m. and cooled to room temperature.