JPH04225539A - Method of manufacturing semiconductor device - Google Patents

Abstract

PURPOSE:To provide a manufacturing method by which the quality of a semiconductor device can be improved by a method wherein a bonding pattern is kept clean and a connecting defective of a fine wire is reduced in a wire bonding process of a COB semiconductor device. CONSTITUTION:A manufacturing method of a COB semiconductor device comprises the following steps: (1) a die attaching process, (2) a wire bonding process, (3) a silicon dam forming process, (4) a sealing process. Since the silicon dam forming process is prepared before the sealing process and after the wire bonding process, a thin film made of silicon is prevented from extending to a bonding pattern.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device in which a semiconductor element is directly attached to a circuit board.

0002

[Prior Art] Chip-on-board technology (hereinafter referred to as COB) is a technology for directly attaching semiconductor elements to a circuit board.
It is a light, thin, short, and small semiconductor device that is often used in small electronic devices such as wristwatches. The conventional manufacturing method for this COB semiconductor device is shown in Figure 2.
It was carried out using the manufacturing method shown in . FIG. 3 explains a conventional example together with a sectional view of a COB semiconductor device. In the first step, the silicon dam 2 is formed at a desired location on the circuit board 1. The silicon dam is formed using a transfer method called stamping or a printing method.

The silicon dam is provided to prevent the sealing resin 5 from flowing out. Because silicone has hydrophilic properties, it is commonly used as a dam to repel the sealing resin. The silicon dam is dried after being formed on the circuit board.
In the step, the semiconductor element 3 is bonded to a desired location within the silicon dam on the circuit board. This process is usually called die attach. In the third step, the wiring pattern 6 on the circuit board (hereinafter referred to as a bonding pattern) and the electrode on the semiconductor element bonded on the circuit board are electrically connected with the thin wire 6. In a process commonly called wire bonding, a wire bonding machine uses thin wires, usually Au wires, to connect them using thermocompression bonding and vibration. In the fourth step, in order to protect the semiconductor elements and thin wires on the circuit board from the external environment, the semiconductor elements and thin wires are covered with sealing resin 5 within the range of the silicon dam on the circuit board.
This is usually called the sealing process. Epoxy resin is usually used as the sealing resin.

The above manufacturing method has been known as a method for manufacturing COB semiconductor devices.

[0005]

[Problems to be Solved by the Invention] However, in the conventional manufacturing method, when forming a silicon dam, silicon flows out to the surrounding area due to capillary phenomenon, and as a result, the bonding pattern where thin wires are connected in the wire bonding process is a thin film of silicon. It was often covered with In order to reliably connect thin wires with wire bonding, it is absolutely necessary to keep the bonding pattern clean, and once a thin film of silicon is formed on the bonding pattern,
There was a problem in that connection failures of thin wires often occurred.

In order to solve these conventional problems, the present invention provides a manufacturing method that can keep the bonding pattern clean and eliminate poor connection of thin wires when connecting thin wires in a wire bonding process. The purpose is to

[0007]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention involves performing the step of forming a silicon dam after the wire bonding step, so that when connecting thin wires in the wire bonding step, the bonding The pattern can now be kept clean.

[0008]

[Operation] In the COB semiconductor manufacturing method configured as described above, the bonding pattern is kept in a clean state during the wire bonding process, making it possible to eliminate connection failures of thin wires. .

[0009]

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 and 3. FIG. 1 is a diagram showing the flow of the method for manufacturing a COB semiconductor device according to the present invention, in which a semiconductor element 3 is bonded to a desired location on a circuit board 1 in the die attach step (2). In the wire bonding process (2), the wiring pattern (bonding pattern) 6 on the circuit board and the electrode on the semiconductor element bonded on the circuit board are connected with the thin wire 6. ■
In the silicon dam forming step, a silicon dam 2 is formed at a desired location on the circuit board. The forming method is a transfer method,
Alternatively, a silicon dam can be formed by a drawing method using a dispenser or the like. ■In the encapsulation process, the semiconductor element and thin wires are covered with a sealing resin 5 within the silicon dam on the circuit board in order to protect the semiconductor element and thin wires from the external environment.The sealing resin is usually epoxy. system resin is used.

[0010] In the manufacturing method of the present invention, after the silicon dam is formed, resin sealing is performed in a continuous sealing step immediately after temporary drying, and the silicon dam and the sealing resin can also be dried together at a high temperature.

[0011]

As explained above, the present invention has a significant effect on the quality of COB semiconductor devices by using a simple method in which the silicon dam forming step is performed after the wire bonding step. This has the effect of ensuring the connection of thin wires in the wire bonding process, eliminating connection failures, and at the same time improving the quality of semiconductor devices.

[Brief explanation of the drawing]

FIG. 1 is a process diagram of a method for manufacturing a semiconductor device according to the present invention.

FIG. 2 is a process diagram of a conventional method for manufacturing a semiconductor device.

FIG. 3 is a cross-sectional view of a COB semiconductor device.

[Explanation of symbols]

1 Circuit board 2 Silicon dam 3 Semiconductor element 4 Thin line 5 Sealing resin 6 Wiring pattern

Claims (1)

[Claims] 1. A circuit board, a semiconductor element is directly bonded to the circuit board, the semiconductor element and a wiring pattern of the circuit board are electrically connected by a thin wire, and the semiconductor element is bonded in a range including the thin wire. A method for manufacturing a semiconductor device in which a semiconductor element is sealed with a resin includes the steps of: adhering the semiconductor element to the circuit board; and electrically connecting the wiring pattern of the circuit board and the semiconductor element with a thin wire. , forming a silicon dam surrounding the semiconductor element at a predetermined location on the circuit board after the step; sealing the thin wire and the semiconductor element with resin within the range of the silicon dam; A method of manufacturing a semiconductor device, comprising: