JPH0627962Y2 - Semiconductor device - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application This invention is to protect a semiconductor chip in the event of a sudden temperature change by fixing a temperature sensitive sudden change element such as a thermistor on an upper surface of a semiconductor chip such as a MOSFET through an insulating layer. The present invention relates to a semiconductor device capable of operating a circuit and the like.

(b) Conventional technology In order to prevent damage due to overheating of the power semiconductor chip, a temperature sensor etc. has conventionally been placed in the vicinity of the target semiconductor element, and the sensor output is monitored to provide a protection circuit in the event of an abnormality. Things have been put to practical use. However, since the semiconductor device and the temperature-sensitive sensor are not arranged very close to each other thermally, the temperature rise of the semiconductor chip may not be detected correctly, and especially when a sharp rise change occurs. There is a possibility that the overheated state will be detected after a delay, causing thermal damage to the chip before the protection circuit operates.

In order to solve this problem, the present applicant has filed Japanese Utility Model Application No. 62-1.
In No. 40286, a temperature-sensitive sudden change element such as a thermistor is directly attached to the semiconductor chip, and the chip-on-
A semiconductor device having a chip structure has been proposed. In the proposed semiconductor device, the overheated state of the semiconductor chip can be directly detected by a temperature sensitive abrupt element such as a thermistor without passing through a thermal barrier, so that there is no delay even with a sudden temperature change. There is an advantage that it is possible to follow, the delay of the operation of the protection circuit is eliminated, and the safety is greatly enhanced.

(c) Problem to be Solved by the Invention However, as shown in FIG. 5, the conventional semiconductor device described above has a structure such as a thermistor on the upper surface of a semiconductor chip such as a power MOSFET 52 via an insulating layer having good thermal conductivity (not shown). The temperature-sensitive sudden change element 53 is fixed, and a conductive adhesive 5 such as a silver paste is provided on the side surfaces of the temperature-sensitive sudden change element 53 facing each other.
One end of the wire 55 was attached via the wire 4. In such a wire mounting operation, the temperature-sensitive sudden change element 53 is powered by the power MO.
Although it will be performed in a wiring step after being fixed on the upper surface of the SFET 52, it takes about 1 to 2 hours at about 150 ° C. to cure the conductive adhesive 54 such as silver paste, and the adhesive 54 is cured. Until that time, one end of the wire 55 must be held for a long time so that one end of the wire 55 is located on the side surface of the thermistor 53. Therefore, the wiring work is very troublesome and the workability is poor. Moreover, after attaching the wire 55 to the thermistor 53 with the adhesive 54 in advance, when it is tried to fix it to the upper surface of the power MOSFET 52 again, it takes about 1 to 2 hours at 150 ° C. to cure the insulating layer. Therefore, it is very troublesome to fix the thermistor 53 with the wire 55 in the meantime. Further, the thermal cycle generated in the chip itself in use may cause the bonding wire connection portion to be peeled off, resulting in a problem in reliability.

An object of the present invention is to provide a semiconductor device capable of mounting a bonding wire on a temperature-sensitive abruptly changing element such as a thermistor on the upper surface of the temperature-sensitive abruptly changing element in a short time and improving workability and reliability during manufacturing. Especially.

(d) Means for Solving the Problem A semiconductor device of the present invention is a semiconductor device in which a temperature-sensitive sudden change element is fixed to an upper surface of a semiconductor chip via an insulating layer, and a predetermined temperature is set at two positions on the upper surface of the temperature-sensitive sudden change element. It is characterized in that an electrode surface for wire bonding is formed with a width gap.

(e) Function In this invention, since the electrode surface (pad) for wire bonding is located on the upper surface of the temperature-sensitive sudden change element, it is not necessary to hold the wire by some means when performing wire bonding. In addition, since the wire is connected to the electrode surface by a known wire bonding technique such as thermocompression bonding or ultrasonic waves without using an adhesive for the connection work, it is not necessary to hold the wire for a long time and the connection state is stable. .

(f) Embodiment FIGS. 1A to 1C are a plan view, a side view and a front view, respectively, of a semiconductor device according to an embodiment of the present invention.

Circuit patterns 5a to 5e are formed on the ceramic base 6. The power MO is applied to the central circuit pattern 5a of the circuit patterns 5a to 5e by the conductive adhesive 4.
SFET1 is fixed. This power MOSFET
A thermistor 2 is fixed to the upper surface of 1 by an insulating adhesive 3. Further, lead terminals 10a to 10e are attached by solder 9 to the circuit patterns 5a to 5e, respectively. The source electrode surface 12 of the power MOSFET 1 and the circuit pattern 5c are connected by wire bonding, and the gate electrode surface 13 and the circuit pattern 5d are connected by a wire 7. further,
Wires 8 connect between the circuit patterns 5 b and 5 e and two places on the upper surface of the thermistor 2. These wires 7 and 8 are connected in a single wiring step by a known bonding technique such as thermocompression bonding or ultrasonic (thermocompression) bonding. The upper surface of the ceramic base 6 configured as described above is covered with the epoxy resin 11.

2A and 2B are external views of the temperature-sensitive sudden change element used in the semiconductor device.

In FIG. 2 (A), the thermistor 2 is obtained by cutting a barium titanate disk into a bulk shape. The bulk upper surface of this barium titanate is electrolessly plated with nickel, and then silver paste is baked to form the electrode surface 22. After forming the electrode surface 22, the slit 21 is formed by using dicing, a diamond cutter, a laser cutter or the like. This slit 21 corresponds to the gap of this invention.

In the example shown in FIG. 2B, the thermistor 2a has slits 21a and 21b formed by dicing or a cutter (diamond cutter or laser cutter). In FIGS. 2A and 2B, slits 21, 21a and 2 are formed.
The width and depth of 1b influence the resistance value of the thermistor, and similarly, both slits 21a, 2 in FIG.
The resistance value changes by changing the interval of 1b.

As described above, according to this embodiment, as shown in FIG. 3, the circuit patterns 5b to 5e, the source electrode surface 12 and the gate electrode surface 13 of the power MOSFET 1, and the electrode surface 22 of the thermistor 2 are all the upper surface of the power MOSFET 1. Located on the side. Therefore, the wire 8 can be connected to the electrode surface 22 of the thermistor 2 simultaneously with the wire bonding of the wire 7 to the source electrode surface 12 and the gate electrode surface 13 of the power MOSFET 1, and the connection work of the wire 8 can be extremely facilitated. At the same time, wiring can be performed in a short time.

FIGS. 4A to 4D are views showing another embodiment of the present invention.

As shown in FIG. 4 (A), five terminals 47a to 47e are provided.
And the heat sink 41 having the mounting portion 42 is formed in a hoop shape. The heat sink 41 is made of Cu, for example.
The plate is plated with Ni. Terminals 47a to 47
Only the central terminal 47c of e is integrated with the heat sink 41. The other terminals are integrated with the central terminal 47c by a tie bar 46. Heat sink 41
The mounting portion 42 is plated with silver to improve conductivity.

As shown in FIG. 2B, the mounting portion 4 of the heat sink 41
The power MOSFET 43 is mounted on 2. This power M
A source electrode surface and a gate electrode surface are formed on the upper surface of the OSFET 43, and the thermistor 44 described above is fixed via an insulating layer. As described above, the upper surface of the thermistor 44 is provided with a predetermined gap, and the electrode surface is formed at two places. In the power MOSFET 43, the drain is formed on the bottom surface and is electrically connected to the mounting portion 42. On the other hand, on the upper surface of the power MOSFET 43, the electrode surface of the thermistor 44 is connected to the terminals 47a, 47b, 47d, as well as the source electrode surface and the gate electrode surface.
47e are simultaneously connected by wire bonding.

After that, as shown in FIG. 7C, the mounting portion 42 and the power MOSFET 43 are covered with a resin 45,
Further, the tie bar portion 46 is cut as shown in FIG. This semiconductor device 40 is a TO
Heat sink 41 and resin package 45 to match the external dimensions of a standardized package such as -220.
By forming a power M with built-in thermistor
OSFET is a conventional packaged power MOSF
It can be configured with the same dimensions as ET.

As described above, in the embodiment of the present invention, it is possible to monitor the rising state of the chip temperature with high accuracy without separately providing an external temperature sensor or the like, and the protection circuit can be operated without delay when the temperature rises rapidly. At the same time, since the standard IC package such as TO-220 can be used as it is, compatibility can be provided in mounting. If the power MOSFET is inserted in series with the main circuit and the thermistor detects that the power MOSFET has reached a predetermined temperature, the current to the power MOSFET is cut off, and this semiconductor itself is used as a thermostat. It is also possible to simplify the external circuit.

In this embodiment, the power MOSF is used as the semiconductor chip.
Although the ET is taken as an example, the present invention can be similarly applied to other MOSFETs and bipolar transistors. Further, the temperature abrupt change element is not limited to the thermistor.

(g) Effect of the Invention According to this invention, since the electrode surface for wire bonding is formed on the upper surface of the temperature-sensitive sudden change element fixed to the upper surface of the semiconductor chip, it is not necessary to use an adhesive to connect the wire. During the wire bonding work of the semiconductor chip, the wire bonding can be performed on the electrode surface of the temperature-sensitive sudden change element in the same process, the wiring work can be extremely facilitated, the manufacturing process can be shortened, and the bonding wire There is an advantage that reliability can be improved without the connection portion peeling off.

[Brief description of drawings]

1 (A) to 1 (C) are a plan view, a side view and a front view of a semiconductor device according to an embodiment of the present invention, and FIGS. 2 (A) and 2 (B) are all semiconductor devices according to the present invention. FIG. 3 is an external view showing a thermistor which is a temperature-sensitive sudden change element forming a part of FIG. 3, FIG. 3 is a view showing a wiring state in the same semiconductor device, and FIGS. 4 (A) to 4 (D) are different views of the semiconductor device of the present invention. It is a figure which shows the Example of. FIG. 5 is a plan view showing a conventional semiconductor device. 1 ... Power MOSFET (semiconductor chip), 2 ... Thermistor (temperature-sensitive sudden change element), 21 ... Slit (gap), 22 ... Electrode surface.

Claims (1)

[Scope of utility model registration request] 1. A semiconductor device in which a temperature-sensitive sudden change element is fixed to an upper surface of a semiconductor chip via an insulating layer, and an electrode surface for wire bonding is provided with a gap of a predetermined width provided at two positions on the upper surface of the temperature-sensitive sudden change element. A semiconductor device comprising: