RU2571880C1 - Microelectronic components mounting method - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: as per the preset coordinates in a metal circular plate openings are shaped for unpacked chips. Adhesive ribbon is strained to one of outer surfaces of the metal circular plate with its sticky side inwards the plate. Unpacked chips are set as per the preset coordinates by their contacts pads onto surface of the adhesive ribbon, then they are sealed and the adhesive ribbon is removed. Polyimide photosensitive lacquer is applied and openings are formed in it. Switching is performed by vacuum metal deposition via thin strippable mask or photolithography processes are used upon vacuum-plasma metal deposition. A layer of dielectric is applied again and windows are formed in it. The last metallisation layer is applied, switching is formed with contact pads and chip components are mounted.

EFFECT: reduced labour intensity and improved reliability of microelectronic units, reduced weight and dimensions of microelectronic units.

7 dwg

Description

The invention relates to electronic equipment and can be used for surface mounting of microelectronic components into multi-chip modules, microassemblies and modules with internal installation of components.

A known method of mounting electronic components with ball leads by the inverted crystal method, including applying adhesive to the contact surface of the component with solder balls, installing the component on the mounting surface of the substrate, melting the balls with solder under the adhesive layer, aligning the ball leads with the contact pads of the substrate, connecting the ball leads with contact the substrate pads by pressing to the substrate and curing the adhesive [1].

However, the known method has significant disadvantages. The soldered connections of the component are not suitable for visual or automatic optical control, which requires special control methods, since the ideal flatness of the mounting pads is required.

Special matching devices are needed. The maximum contact area of the ball terminal is equal to the area of the contact area on the printed circuit board. Mounting pads dramatically reduce the board area usable for wiring.

A known method of mounting microelectronic components based on flexible-rigid printed circuit boards, including the placement on the basis of previously tested and programmed components, their sealing, metallization and the formation of the necessary layers [2].

Installation of microelectronic components is carried out without the use of solder and tin and the problems associated with heat treatment. Microelectronic components are installed first, then circuit layers are made.

A standard board is not required, the production cycle time is reduced, costs and complexity are reduced, and the reliability problems of the board are reduced.

The disadvantage of this method is the low accuracy of the positioning of the components on the basis of which leads to a trace error of the circuit. Another disadvantage is the separation of crystals. This process operation reduces reliability and increases the complexity of multi-chip modules and microassemblies. The use of packaged electronic components leads to a significant increase in the mass and size characteristics of the nodes.

The task to which the invention is directed is to reduce the complexity of manufacturing and increase the reliability of microelectronic components, reduce their weight and size parameters.

To achieve this goal, in the method of assembling microelectronic components, which includes placing, on the basis of previously tested and programmed components, their sealing, metallization and layer formation, chip-free crystals are used as programmed components, a metal round plate is used for the base, in which holes are formed at specified coordinates under open shell crystals, on one of the surfaces of a metal round plate pull adhesive tape, sticky with the inside side of the plate, the casing-free crystals are placed in contact coordinates on the surface of the adhesive tape, then sealed, the adhesive tape is separated, the polyimide photographic varnish is applied, holes are formed in the polyimide photographic varnish - the windows are opened exactly above the contact pads and the openings of the open-casing crystal, and they are switched by vacuum deposition of metals through a thin removable mask or photolithography after vacuum-plasma deposition of metals from three layers in layers, then apply second a swarm dielectric layer, windows are formed in it, the last metallization layer is applied, switching with contact pads is formed, then the chip components are installed.

Distinctive features of the claimed method is that instead of housing elements, shell-free crystals are used, a metal round plate is used for the base, in which holes for shell-free crystals are formed according to the given coordinates, an adhesive tape is pulled onto one of the external surfaces of the metal plate, the sticky side inside the plate, shell-free the crystals are installed at the specified coordinates by the contact pads on the surface of the adhesive tape, then they are sealed, the adhesive tape is separated, n they wear polyimide phototlack, form holes in the polyimide photolack, open windows exactly above the contact pads and openings of the open-frame crystal, carry out switching by vacuum deposition of metals then through a thin removable mask, or use photolithography processes after vacuum-plasma deposition of metals, at least from two layers in layers, a second dielectric layer is applied, windows are formed in it, the last metallization layer is applied, switching with large contact pads is formed, then Component chip.

The use of a metal round plate allows using it for further processing using microelectronics methods used for semiconductor wafers in the production of microelectronic components. That is, the proposed method contains a minimum number of technological operations that differ from standard in the production of integrated circuits. In the production of microelectronic components in this way, a level of automation is achieved that is comparable to the level of automation of microelectronic productions, since a similar set of technological equipment is used, and this can significantly reduce the cost of production of electronic components and significantly improve quality indicators.

Chipless crystals of integrated circuits are precision mounted on adhesive tape with pads and leads to the adhesive side of the tape at specified coordinates. Initially, standard or specially formed boards with ready-made switching are not required, the use of which greatly complicated the high-precision installation of crystals.

The use of frameless elements significantly reduces the overall dimensions of the electronic unit. During the placement, the electronic components are pressed against the adhesive tape by pads or pins down under a certain load. This operation is used to fix the installed frameless elements for the subsequent operation of applying polyimide varnish.

The proposed method allows to reduce weight and size parameters, eliminates spurious electromagnetic phenomena associated with welded joints, since installation or electrical contact with microelectronic components is carried out without welding by vacuum deposition of metals. Reliability is increased, speed is increased, vibration resistance and heat resistance of radio electronic equipment units are increased. There are no defects associated with welding, namely, short circuits, breaks, voids, residual deformations. The invention is illustrated in FIG. 1 (a, b, c, d, d, f, f.) - the sequence of technological operations of the method of installation of microelectronic components,

Where:

1 - metallic round plate,

2 - uncased crystals,

3 - adhesive tape

4 - layer of polyimide photolac - the first layer of dielectric,

5 - layer switching

6 - the second dielectric layer,

7 - the second layer of switching,

8 - chip components,

9 - compound.

The method is implemented as follows. According to the given coordinates, holes are formed for open-frame crystals in a round metal plate. An adhesive tape 3 is pulled onto one of the outer surfaces of the metal round plate 1, with the adhesive side inside the plate 1. Uncased crystals 2 are set in contact coordinates on the surface of the adhesive tape 3. Contactless crystals 2 are lightly pressed to the adhesive tape 3 to ensure fixation before further operations (Fig. 1a). Sealed with compound 9 (Fig. 1B). The adhesive tape 3 is separated from the surface of the metal round plate 1 (Fig. 1B). Apply polyimide phototlac 4 (Fig. 1d). Form holes in the polyimide photographic varnish 4 (Fig. 1d). Open the windows exactly above the pads and the findings of the open-chip 2 (Fig. 1d). They carry out switching by vacuum deposition of metals through a thin removable mask or use photolithography processes after vacuum-plasma deposition of metals, with at least 5 layers of at least two layers (Fig. 1e). A second dielectric layer 6 is applied (Fig. 1e). Windows are formed in it (Fig. 1e). Apply the last layer of metallization, form a commutation with large pads 7 (Fig. 1e). Then install the chip components 8 (Fig. 1g).

Example.

In an aluminum plate AMg 3M with a thickness of 0.8 mm and a diameter of 100 mm, holes for shell-free crystals are formed in the given coordinates. Then, on one side, the adhesive tape is pulled with the adhesive side inside the plate. Chip-free crystals are installed at specified coordinates by contact pads on the surface of the adhesive tape. Chipless crystals are gently pressed against the adhesive tape to ensure fixation.

Sealing is carried out - an epoxy compound K-400 is applied. The adhesive tape is separated from the surface of the metal round plate. A photodetectable dielectric is applied - a heat-resistant photolacquer FLTP (IVS RAS) (the method of application is centrifugation, thickness 5 μm) (damping is up to 300 ° C). Using photolithography methods, holes are formed in the polyimide photographic varnish - they open windows exactly above the contact pads and the openings of the open-chip crystal. Switching is carried out by the method of vacuum deposition of metals, then through a thin removable mask or using photolithography processes after vacuum-plasma deposition of metals, moreover, at least two layers are deposited in layers — chromium is deposited then copper is deposited with 2 microns (the deposition method is magnetron sputtering). A second dielectric layer is applied. Form windows in it. A metallization finish layer is applied - nickel, then low-temperature solder is applied (the method of application is magnetron sputtering, then solder paste through a stencil). Form switching with contact pads. Then install the chip components.

Thus, the proposed method provides a reduction in the complexity, increased efficiency, reduced weight and dimensions of electronic components.

Information sources

1. RF patent No. 2331993.

2. US patent No. 8193042 - prototype.

Claims (1)

The method of installation of microelectronic components, including placement on the basis of previously tested and programmed components, their sealing, metallization and the formation of layers, characterized in that the programmed components are used without crystals, for the base they use a metal round plate in which holes are formed at specified coordinates for open crystals, on one of the surfaces of a metal round plate pull adhesive tape, sticky side inside the plate, the casing-free crystals are placed in contact coordinates on the surface of the adhesive tape by contact pads, then they are sealed, the adhesive tape is separated, the polyimide photographic varnish is applied, holes are formed in the polyimide photographic varnish - the windows are opened exactly above the contact pads and the openings of the open casing, switching is carried out by vacuum spraying through a thin removable mask or photolithography after vacuum-plasma deposition of metals from three layers in layers, then a second layer of di lektrika form a window therein, the last applied layer of metallization formed with switching contact surfaces, then mounted chip components.

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