JPH0789575B2 - Printed wiring board for mounting semiconductor chips - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board used in a semiconductor device having a structure in which a semiconductor chip is mounted and the periphery thereof is sealed with a resin material. The present invention relates to a printed wiring board having a resin flow stop frame for.

(Prior Art) When mounting a semiconductor chip on a printed wiring board, it is common to cover the semiconductor chip with a liquid thermosetting resin after conductively connecting the circuit chip to a circuit pattern, and then heat-cure the resin to seal it. Is being carried out. Therefore, the printed wiring board used for this purpose aims to prevent the sealing resin from spreading to unnecessary places and to improve the reliability of the sealing by ensuring a sufficient height of the sealing resin. Often, a resin flow stop frame is provided around the portion where the semiconductor chip is to be mounted.

As a method for forming this frame, a simple method is disclosed in Japanese Patent Laid-Open No. 59-105342.
As in Japanese Patent Laid-Open Publication No. JP-A No. 2003-187, a frame-shaped molded body previously molded in a predetermined frame shape may be attached to a predetermined position using an adhesive. However, with this method, the steps such as forming the frame-shaped molded body, positioning of pasting, and adhesion are extremely complicated, and the product price is not preferable. Therefore, as a method for easily forming the flow stop frame, there is a method of applying and curing an insulating resin in a frame shape by using a screen printing method or the like, as disclosed in JP-B-49-43873. And, as a method further improving this method, as in Japanese Utility Model Laid-Open No. 55-25381, a method of using a normally used solder resist as a resin flow stop frame rather than forming the resin flow stop frame as an independent step. Is.

However, when the screen printing method is used, there is a limit to the thickness of the printed material that can be formed by one printing by the usual method, and in some cases, the required frame height is required unless printing and drying are repeated many times. You may not get it. In that case,
In the case of a thick film wiring board, the thick film pattern made of the same material as each thick film element is laminated at the same time as the thick film element forming process as in JP-A-59-117253 to increase the film thickness. There is also a method.

However, the invention proposed in Japanese Patent Laid-Open No. 59-117253 is based on the premise that the same material as each thick film element is used and the number of dam formation steps is not increased.
Moreover, the electrical characteristics of the thick film material are not a problem, and the purpose is merely to secure the necessary film thickness. Further, the purpose of forming the dam is to prevent the semiconductor chip sealing resin from entering the thick film resistor portion, and is not intended to ensure the resin sealing of the semiconductor chip.

More importantly, in each of the above-mentioned prior arts, only the intention is to reliably prevent the resin sealing from flowing to other parts. No consideration is given to enhancing the function of this kind of sealing resin flow stop frame by adding such a function.

(Problems to be Solved by the Invention) The present invention has been made in view of the above circumstances, and the problem to be solved is that the conventional sealing resin flow stop frame causes resin outflow. Is merely physically prevented, and does not contribute to the electric circuit at all.

Then, an object of the present invention is to impart conductivity to a sealing resin flow stop frame in a semiconductor chip mounting printed wiring board of this type and use this as a part of a circuit. In this way, it is possible to provide a printed wiring board for mounting a semiconductor chip, which has a higher wiring density or a smaller substrate.

(Means for Solving Problems) In order to solve the above problems, means adopted by the present invention will be described with reference to FIGS. 1 to 3 corresponding to the embodiment. A semiconductor in which (2) is mounted on a printed wiring board, and a sealing resin (6) is dripped and flowed into a resin flow stop frame (10) provided so as to continuously surround the semiconductor chip (2) for sealing. In the equipment, the conductive coating film (1) in which the resin flow stop frame (10) becomes a resistor
And the circuit patterns (3) on the insulating substrate (7) are electrically connected by the conductive material coating film (1) ".

This configuration will be described in detail with reference to the drawings. As shown in FIGS. 1 to 3, a resin coating film is formed by forming a conductive coating film (1) directly on the circuit pattern (3) in a continuous frame shape. (10), the resin flow stop frame (10) is used to perform the original resin flow stop, and conductivity is imparted between the circuit patterns (3).

The printed wiring board for mounting the semiconductor chip is the fourth
As shown in FIGS. 6 to 6, a continuous resin flow stop frame (10) is formed by laminating an insulating coating film (8) and a conductive coating film (1) on a circuit pattern (3). With
The conductive coating film (1) can be connected to the circuit pattern (3) through the openings (a) and (b) formed in the insulating coating film (8) to impart partial conductivity. is there.
Further, FIG. 7 shows a case where the present invention is applied to a thick film wiring board, in which the resin flow stop frame (10) is formed at the same time when each thick film element is formed. In the stop frame (10), at least one layer on the upper side of the insulating substrate (7) is a multilayer coating film formed of the conductive coating film (1).

(Operation of the Invention) The present invention adopts the above-mentioned means and has the following operation.

In the printed wiring board for mounting a semiconductor chip according to the present invention, as shown in FIGS. 1 to 3, as a material for a conductive coating film directly formed on a circuit pattern in a continuous frame shape,
If the paste for printed resistors is used, it becomes equivalent to the case where resistors are mounted between the circuit patterns, and the printed wiring board with resistors is obtained. At this time, the resin flow stop frame (10) formed of the conductive coating film (1) may be formed by a screen printing method, or if a larger film thickness is required, a fixed amount is applied. A drawing method using an apparatus may be used.
Even when it is not necessary to provide a resistor between the circuit patterns on the circuit, if a low antibody having a resistance value large enough not to interfere with the operation of the semiconductor is provided between the circuit patterns, the low antibody will be reduced. It serves as a protection circuit that prevents semiconductor damage and malfunction due to static electricity.

Further, in this semiconductor chip mounted printed wiring board, as shown in FIGS. 4 to 6, the insulating coating film and the conductive coating film are laminated on the circuit pattern to form a continuous frame. For example, the resin flow stop frame (10) becomes a jumper wire in the thick film multilayer circuit. Needless to say, this portion also becomes a low antibody due to the conductivity of the conductive coating film.

Further, as shown in FIG. 7, when the present invention is applied to a thick film wiring board, the function as the resistor or the jumper wire described above is achieved by the resin flow stop frame (1
No additional step is required to form the resin flow stop frame (10) provided in step (0). Further, in the case of a thick film substrate, the coating film is generally multi-layered, and even if a normal screen printing method is used, the resin flow stop frame (10) has a sufficient film thickness.

As described above, according to the present invention, the resin flow stop frame (10) functions not only as a resin flow stop, but also as a resistor and a jumper wire.

Next, the present invention will be described with reference to examples.

(Example) Example 1 In the example shown in FIGS. 1 to 3, the etching method was used.
After forming a circuit pattern (3) with 35 μm copper foil, electroplating nickel 5 μm and gold 0.5 μm on the surface, and as a conductive coating film (1) on it, sheet resistance value 1 MΩ by screen printing method. The resin-based carbon paste of / □ was applied by printing in a continuous frame shape and heat-cured. This resin-based carbon paste is intended to function as a protective resistance of the semiconductor, and the optimum value of its conductivity is determined by the characteristics of the semiconductor chip.

Example 2 In the example shown in FIGS. 4 to 6, after the circuit pattern (3) is formed in the same manner as in Example 1, the circuit pattern requiring the conductive connection with the jumper wire (2). (3) An insulating coating film is formed by using an epoxy solder resist that is usually used, except for the above two points (a) and (b) and the part where the semiconductor chip is to be mounted. (8)
Was formed. Further, as a conductive coating film (1) having a frame shape slightly larger than the frame, a resin silver paste was applied by printing, and then cured by heating. At this time, the resin-based silver paste is intended to function as a jumper wire.

Example 3 In the example shown in FIG. 7, after forming the circuit pattern (3) in the same manner as in Examples 1 and 2, the insulating coating film (8) is formed in the same manner as in Example 2. Next, the silver coating film (9) is formed at the same time when the silver electrode for the printed resistor is formed. Further, the carbon coating film (9a) is formed when the printed resistor is formed, and the insulating coating film (8a) is formed again when the protective film of the printed resistor is formed. A screen printing method was used for forming these coating films. Further, the silver coating film (9) functions as a jumper circuit as in the second embodiment. Further, as the resin flow stop frame, a sufficient thickness can be secured, and a step of adding it for forming the frame is unnecessary.

(Effects of the Invention) As described above, according to the semiconductor chip mounting printed wiring board according to each invention, the resin flow stop frame can be used as a part of the circuit pattern, and the material and shape of the conductive coating film can be improved. By selecting an appropriate one, various functions such as the electrostatic breakdown prevention treatment of the semiconductor chip, the printed resistor, the jumper wire and the like can be added, and the surface of the printed wiring board can be efficiently used. This greatly contributes to high density and downsizing of the printed wiring board, and it is possible to provide a printed wiring board that satisfies the requirements of light, thin, short and small electronic devices.

Further, when the present invention is applied to a thick film wiring board, it becomes possible to simultaneously form a resin flow stop frame using the same material in the process of forming each element on the board by the screen printing method. There is no need to add the formation as a separate step,
Therefore, it becomes possible to provide a semiconductor chip mounting printed wiring board with a resin flow stop frame having a circuit function at a low cost.

[Brief description of drawings]

FIGS. 1 to 3 show a semiconductor chip mounting printed wiring board according to the present invention. FIG. 1 is a plan view of the semiconductor chip mounting printed wiring board, FIG. 2 and FIG. 3, respectively. FIG. 3 is a sectional view taken along line XX and YY of FIG. 1. Further, FIGS. 4 to 6 show a semiconductor chip mounting printed wiring board according to another embodiment, and FIG. 4 is a plan view of the semiconductor chip mounting printed wiring board, FIGS. Each of the figures is a cross-sectional view taken along line XX and YY of FIG. Furthermore, FIG. 7 is a cross-sectional view of a semiconductor chip mounting printed wiring board according to still another embodiment. Explanation of reference numerals 10 ... Resin flow stop frame, 1 ... Conductive coating film, 2 ... Semiconductor chip, 3 ... Circuit pattern, 4 ... Bonding wire, 5 ... Die pad, 6 ... Sealing resin, 7 …… Insulating substrate, 8 …… Insulating coating, 9 …… Silver coating, 9a …… Carbon coating, 8a …… Insulating coating, (a), (b) …… Conductive connection on the circuit pattern The part to be done.

Claims (2)

[Claims] 1. A semiconductor device in which a semiconductor chip is mounted on a printed wiring board, and a sealing resin is dripped and flowed into a resin flow stop frame provided so as to continuously surround the semiconductor chip for sealing. A printed wiring board for mounting a semiconductor chip, characterized in that the anti-flow frame is formed of a conductive coating film which becomes a low antibody, and the circuit patterns on the insulating substrate are electrically connected by the conductive coating film. 2. The semiconductor chip mounting device according to claim 1, wherein the resin flow stop frame is a multilayer coating film in which at least one layer on the upper side of the insulating substrate is formed of a conductive coating film. Printed wiring board.