JPS62254455A - Pinless package and mounting method thereof - Google Patents

Abstract

PURPOSE:To form the pitch between terminals in a microscopic manner by a method wherein a pick-up terminal with which an electric connection is performed with a circuit substrate, is provided on the mounting surface of the main body of the title package, and they are connected using an insulative bonding agent. CONSTITUTION:A package and a printed wiring substrate are electrically connected by interposing a bonding agent between them and by performing positioning and pressure-welding operations. They can be pressurewelded by coating anisotropic conductive bonding agent on the whole surface of the connecting part of a circuit. As for conductive particles it is desirable to use abrasive grain like particles, because they produce an anchor effect on the surface of the opposing circuits. Pertaining to the method of adhesion, metal-plating in which conductive superhard material grains are misced is performed on the circuit of the circuit substrate or the pick-up terminal of the pinless package opposing to said circuit, and they are pressure-welded through the intermediary of an insulative bonding agent. As said particles are in an abrasive granular state and they have a high degree of hardness, they break the insulative bonding agent when the pressure-welding work is performed, they cut into the pick-up terminal of the package and the circuit of the circuit substrate and an electrical continuity is performed.

Description

[Detailed Description of the Invention] (Technical Field of the Invention) The present invention involves preparing an advanced circuit board on which electronic circuit elements are mounted, and mounting the circuit elements thereon using an anisotropic conductive adhesive or the like. The present invention relates to a pinless package in the form of a high-density circuit element that can be automated for processing.

(Prior Art and Problems) Conventionally, various components have been mounted on circuit boards such as printed wiring boards of electronic devices mainly by soldering. Today, electronic components are becoming lighter, thinner, and smaller.

At the expense of lowering mounting costs and improving reliability, we are entering an era of planar mounting using reflow soldering methods. For this reason, the component elements mounted on the board have been made into chips and have been improved to be suitable for automatic mounting, and the solder has also been improved to have high performance suitable for this purpose.

However, as long as soldering relies on connections, heat damage to components such as the package body is unavoidable, and soldering on molds and lead frames also serves to protect the semiconductor by absorbing heat over time. Therefore, the original size of the package is 20
This is one of the reasons why it is not possible to downsize the size by ~150 times. In addition, devices such as LSIs with narrow pin pitches have a large number of pins, resulting in various problems such as poor connections after reflow or short circuits between pins due to bridging of excessive solder.

(Object of the Invention) In view of the above-mentioned problems, the object of the present invention is to provide a functional passive element, cabinet, and capacitor, excluding a mold and a lead frame larger than the mother body.

Coil chip itself, diode, transistor, I
The object of the present invention is to provide a pinless package that can be bonded to a printed circuit board using an anisotropic conductive adhesive or the like, with C in the form of an almost bare chip, making soldering unnecessary.

(Structure of the Invention) The present invention relates to a pinless package in which a takeout terminal for electrically connecting to a circuit board is provided on the mounting surface of the package body in a package to be mounted as an electronic circuit element, and the pinless package. This is a method for mounting a package on a circuit board.

To explain the present invention with reference to the drawings, Fig. 2 shows an example of a conventional package, in which the package (1) is equipped with a large number of pitches (2) corresponding to the built-in circuits, and the printed wiring board (3) is equipped with a number of pitches (2) corresponding to the built-in circuits. The circuit pattern (4) of the connection part corresponding to the pitch (2) above is printed with solder plating or cream solder, and (2) and (4) are made by temporarily bonding the package (1) and soldering. Connected.

FIGS. 1(a), (b), and (c) illustrate the package of the present invention, and FIG. 1(d) shows a printed wiring board on which the package of the present invention is mounted.

The square flat package (5) and the FP type circular flat package (6) each have a printed wiring board (
Connection part patterns (8) and (9) corresponding to the circuit connection part patterns (8' and 9') of 1) are provided. The circuit connection patterns in Figures 1 (A) and (B) are both printed on the package body, but as shown in Figure 1 (C), the outer edge (10) is provided on the package, and the circuit connection patterns are printed on the package body as shown in Figure 1 (C). Pattern (9) may also be printed.

The printed wiring board on which the package is mounted is made of ceramic glass, glass epoxy, glass triazine, glass diallyl phthalate, polyphenylene oxide, polyester film, and other materials selected depending on the application. The same materials as conventional ones can be used for the printed wiring board and the circuit connection part of the package (extracting terminals).

In other words, a substrate made of glass epoxy, glass triazine, glass diallyl phthalate, etc., printed with conductive ink on a metal foil such as copper foil, or a polyphenylene oxide, polyester, or polycarbonate film, or a glaze film formed on a ceramic plate or glass plate. etc. are all used.

The electrical connection between these packages and the printed wiring board is achieved by interposing an adhesive between the two, aligning them, and pressing them together.

That is, conventionally, a method of applying a conductive adhesive to a circuit connection pattern and crimping it is known, but the application is difficult because the pitch of the electrode terminals is narrow. In the present invention, an anisotropic conductive adhesive can be applied to the entire surface of the circuit connection part (including parts other than the terminals) and the circuit can be crimped.

As the conductive particles in the anisotropic conductive adhesive, abrasive-like particles, such as polyhedral or sugar-like particles having a surface shape such as a large number of protrusions or ridges, are preferable because they provide an anchoring effect on the opposing circuit surface. .

Such abrasive conductive particles include abrasive metal particles of nickel, cobalt, iron, etc. produced by the carbonyl method, abrasive metal alloy particles of alloys of these metals produced by the atomization method or stamp method, or The surface of superhard material particles or these or abrasive metal oxide particles is made of nickel, copper, silver, gold, platinum, rhodium, or ruthenium.

Examples include abrasive conductive particles plated with highly conductive metals such as osmium and palladium. Examples of the abrasive conductive superhard material particles include carbides, borides, and silicides of Group I, VB, and VIB of the periodic table, and particles of lanthanum borides. Its particle size is usually 0.
It is 3 to 50 μm. Specifically, carbides and borides of titanium, niobium, tantalum, chromium, molybdenum, and tungsten.

A paste mainly composed of particles of silicide, lanthale boride, etc. and colloidal metal powder is applied and pressed. On this occasion,
An insulating adhesive may be used.

As an adhesion method, such conductive superhard material particles may be mixed into the circuit of the circuit board or the lead-out terminal of the pinless package facing the circuit board and plated, and then crimped with an insulating adhesive. Alternatively, it is also possible to form a coating film of a paste containing a conductive superhard material on the circuit or the terminal, and press the paste with an insulating adhesive.

Since these particles are abrasive-like and have a high hardness, they break the insulating adhesive layer during crimping and bite into the take-out terminals of the package and the circuits of the circuit board, thereby establishing electrical continuity.

In this case, surface portions other than the circuit connection portions may also be bonded with an insulating adhesive. In order to incorporate it into the package manufacturing process and the process of mounting it on a circuit board, it must be possible to process it in the same amount of time as conventional bonding and soldering processes. Therefore, as the insulating adhesive, it is usually preferable to use a cyanoacrylate-based "instant adhesive" or a (meth)acrylate-based "anaerobic adhesive" or "capsule curing adhesive" constant-speed hardening adhesive. Additionally, epoxy resin adhesives and silicone resin adhesives may also be used as long as they do not cause any problems in the process.

The circuit connection part, so-called terminal, is DIP, 40 pins, super LS
It is common for I chip carriers to have more than this, and the larger the contact area, the lower the connection resistance, but if it is too large, the pitch between the terminals will become narrower as the number of terminals increases, making it difficult to ensure insulation between the terminals. become. Conversely, reducing the contact area requires high precision in positioning the terminals between the package and the board, and the number of pins increases in VLSI chip carrier packages, resulting in a pitch of 30 μm.
Select the appropriate terminal size according to the actual requirements.

Care must be taken as the height of the package terminals greatly affects the results of adhesive connections. Package body and board body (
It is desirable that the clearance (including resist in areas other than the terminals, if any) is within about one shoe after crimping connection. The smaller the thickness of the adhesive layer, the greater the adhesive strength, which means that the least amount of adhesive is consumed and the appearance after adhesion is more attractive. As described above, the height of the terminals must be determined based on the bonding state, but basically it is preferable that these terminals be on the same plane as the package body and the substrate body. However, the terminals of the package may have a structure that is recessed to some extent within the surface, and this is a convenient structure when the terminal surface is sealed with a film to protect it or when it is handled as a tape carrier type package. When using the above insulating adhesive,
Although it depends on the material of the package and substrate surface, by appropriately selecting the type of adhesive, the interfacial tension of the adhesive itself will allow the adhesive to spread to every corner of the adhesive surface. Conversely, it is also possible to use the interfacial tension of the adhesive to drip the adhesive after aligning the opposing terminals or during pressurization.

This method is advantageous when the pot life of the adhesive is short.

Example 1 A flat package (circuit width 0.3
#1111. A glass epoxy laminate with a pitch of 0.658 and a printed wiring board covered with 18 μm thick copper foil was etched to form a total of 100 circuits with the same pitch width as the package. . The following paste was applied to the part (8') in FIG. 1(d) to a thickness of about 10 μm (composition is heavy matrix).

Adhesive (A agent) (Product name: Bondcony-One.

Manufactured by Konishi Co., Ltd. > ioo part WSi2 (particle size 1 to 6μ9, manufactured by Japan Shinkinzoku Co., Ltd.) 20 parts TiC (particle size 8 to 17μ, manufactured by Showa Denko) Component (Agent B) was applied in a tingling manner, placed on the wiring board, aligned, and a pressure of about 1 ONg was applied from above for about 2 seconds.

In this way, resistance values between circuit connections at a total of 50 points were measured.

Resistance measurement value (Ω) 70℃95%RH Initial value Average after 2000 hours treatment 0.256 0.275 Maximum
0.303 0.361 minimum 0.237
0.242 The insulation resistance value between each terminal was also measured.

Insulation resistance value between terminals (Ω) 10℃95%RH Initial value Average after 2000 hours treatment 6 x 10128 x 1011 Maximum 24 x 10129 x 1012 Minimum 1.8
X10123

(Effects of the Invention) The package of the present invention is provided with a take-out terminal for electrically connecting to the circuit board on the mounting surface of the main body, and an anisotropic conductive adhesive or an anisotropic conductive adhesive is used to obtain sufficient conductivity during bonding. It is characterized in that it can be processed and firmly connected using an insulating adhesive that hardens in a short time. Therefore, unlike conventional products, there is no need to attach pins to the outside of the package body and connect them by soldering. Therefore, the pitch between the terminals of the connection portion can be made extremely fine, and the extra board area due to the provision of pins can be omitted. Furthermore, since there is no need to consider thermal shock due to soldering, there is a wide selection range of IC elements, no complicated processes are required, and damage to the board caused by this can be avoided. Since it can be mounted on a substrate in a nearly bare state, it can be made thinner, more compact, and suitable for process automation.

[Brief explanation of drawings]

Figures 1 (a), (b), and (c) are perspective views showing various aspects of the pinless package of the present invention, and Figure 1 (d) is (a).
FIG. 3 is a perspective view of a printed wiring board provided with a circuit connection pattern corresponding to the circuit connection pattern of the pinless package (b). FIGS. 2(a) and 2(b) are perspective views of a conventional package and a printed wiring board. (1)...Conventional product package, (2)...Pitch. (5)(6)...Pinless package, (7)...
Printed wiring board, (8) (9)...Circuit connection part of pinless package, (8'>(9')...Circuit connection part (A) of wiring board
(/%] (d)

Claims (4)

[Claims] (1) A pinless package, which is used for mounting as an electronic circuit element, and has a lead-out terminal for electrically connecting to a circuit board on the mounting surface of the package body. (2) Mounting of a pinless package characterized in that a pinless package in which a lead-out terminal for electrical connection with a circuit board is provided on the mounting surface of the main body is crimped to the circuit board using an anisotropic conductive adhesive. Method. (3) The mounting method according to claim 2, wherein superhard material particles are used as the conductive particles in the anisotropic conductive adhesive. (4) When electrically connecting a pinless package that has a take-out terminal for making an electrical connection with the circuit board on the mounting surface of the main body with the circuit board, the circuit board or the take-out terminal of the pinless package should be connected to the circuit board. It is characterized by plating with conductive carbide material particles mixed in, or by forming a coating film of paste containing conductive carbide material particles on the circuit or terminal, and then press-bonding with an insulating adhesive. How to implement a pinless package.