JPH0119419Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a thick film circuit device in which a circuit is formed on a substrate by printing or the like, and in particular, it has a part to which a chip is bonded on one side of the substrate and a printed circuit on the other side. The present invention relates to a thick film circuit device having a crossover portion.

For thick film circuit devices in which circuits are formed on substrates by printing or other means, the technology for bonding chip components such as ICs and transistors is important.
This is because most of the deterioration of these chip parts is due to bonding parts. Therefore, in thick film circuit devices, it is required to form highly reliable bonding portions.

Conventionally, bonding has been performed with the substrate of the thick film circuit device mechanically fixed. That is, various types of bonding have been performed by fixing the substrate, particularly the bonding portion of the substrate, with a suitable jig or device. However, such mechanical fixing has the disadvantage of requiring complicated operations. Furthermore, some thick film circuit devices have portions requiring bonding on one side of the substrate and a printed circuit crossover on the other side. 1 and 2 are plan views showing an example of such a thick film circuit device, with FIG. 1 showing one surface of the thick film circuit device, and FIG. 2 showing the other surface. Showing the back side. As is clear from FIG. 1, there is a die bonding portion 1 on the surface of this thick film circuit device.
and wire bonding portions 2, 2, 2, 2 are present. On the other hand, on the back side of this thick film circuit device, as is clear from FIG. 2, there is a portion 3 where the printed circuit patterns cross over, ie, a portion where the printed circuit patterns overlap. The portion 3 where the printed circuit crosses over has a relatively large thickness compared to the other printed circuit portions 5,6. This is because the crossover portion 3 is constructed by overlapping the printed circuit patterns 5 and 6 with an insulating layer interposed therebetween, and the thickness of this insulating layer is larger than that of the printed circuit patterns 5 and 6. This is because it is extremely thick. Therefore, in the thick film circuit device shown in FIGS. 1 and 2, when bonding is performed on the bonding portions 1 and 2 on the front surface, the presence of the crossover portion 3 on the back surface prevents the substrate from wobbling. become. That is, since the thickness of the crossover portion 3 is thick, the board cannot ensure horizontality. If the substrate cannot be kept horizontal, it is difficult to perform bonding reliably even if the substrate is mechanically locked. In particular, in wire bonding, if the substrate is inclined due to its nature, the adhesive strength is low and positioning with respect to the bonding part is extremely difficult.

Therefore, the main objective of this invention is to provide a thick film circuit device which overcomes the above-mentioned drawbacks and is provided with a structure such that reliable bonding is achieved.

The thick film circuit device according to this invention is a thick film circuit device that is provided with a bonding portion for bonding an electronic component chip on one side of a substrate, and a portion where a printed circuit is crossed over on the other side of the substrate. In this thick film circuit device, the substrate wobbles when the electronic component chip is bonded to a portion of the other surface where the printed circuit is not provided in cooperation with a portion where the printed circuit is crossed over. The present invention is characterized in that a dummy pad is formed having a thickness substantially equal to that of the portion where the printed circuit is crossed over.

The above objects and other objects and features of the present invention will become more apparent from the following detailed description with reference to the drawings.

FIG. 3 is a plan view showing one embodiment of this invention, and is a second embodiment of the conventional thick film circuit device.
Corresponds to the figure. As is clear from FIG. 3, in this embodiment, three dummy pads 10, 10, 10 are formed on the back surface of the substrate 4. Other points are similar to the conventional thick film circuit device shown in FIG. 2, so corresponding parts will be given corresponding reference numerals and a description thereof will be omitted. Further, the other surface, that is, the front side, of the substrate 4 in the embodiment shown in FIG. 3 is the same as that in FIG. 1 shown for the conventional thick film circuit device. Each dummy pad 10 is formed to have approximately the same thickness as the crossover portion 3. Therefore, in the thick film circuit device of this embodiment, when bonding is performed on the bonding portions 1 and 2 on the front surface shown in FIG. 1 with the back surface shown in FIG. 3 facing down, the dummy pad 10 cooperates with the crossover portion 3 to prevent the substrate from wobbling. That is, the dummy pad 10 has the function of compensating for the thickness of the crossover portion 3. Therefore, when bonding is performed in the thick film circuit device of this embodiment, highly reliable bonding can be obtained and bonding with uniform bonding strength can be achieved. In addition, each dummy pad 1
The position and number of 0s are not limited to those shown in FIG. That is, the appropriate location and number are selected depending on the shape of the substrate and the position of the portion to be bonded. Further, although it is preferable that the thickness of each dummy pad 10 is exactly the same as that of the crossover portion 3, it is not necessarily necessary that the thickness of each dummy pad 10 be the same as that of the crossover portion 3. The crossover portion 3 is composed of three layers: a first layer conductor, an insulator layer, and a second conductor layer forming the printed circuit pattern 6. The thickness is governed by the thickness of the insulator layer. This is because the thickness of the insulating layer is extremely large compared to each of the printed circuit patterns 5 and 6. Therefore, each dummy pad 10 is
It may be composed of only an insulating layer, or it may be composed of an arbitrary combination of an insulating layer and the materials constituting each printed circuit pattern 5, 6. By forming each dummy pad 10 with the material forming the insulator layer and each printed circuit pattern 5, 6 as described above, each dummy pad 10 is made of the material forming each printed circuit pattern 5, 6 and each insulator layer. At the same time, it can be easily formed.

FIG. 4 is a plan view showing another embodiment of this invention. In the embodiment shown in FIG. 4, the surface of substrate 4 is similar to the surface of the conventional thick film circuit device shown in FIG. A feature of the embodiment shown in FIG. 4 is that a dummy pad 11 having the function of compensating for the thickness of the crossover section 3 is formed on the back side of the bonding sections 1, 2. That is, the dummy pad 11 is connected to the bonding portion 1,
2 and the substrate 4 are placed in between. The rest of the structure is the same as that of the embodiment shown in FIG. 3, so corresponding parts will be designated with corresponding reference numbers and a description thereof will be omitted.

The advantage of the embodiment shown in FIG. 4 is that a dummy pad 11 having a certain area is formed on the back side of the bonding parts 1, 2, so that the substrate 4 becomes very stable during bonding.
This means that even if the substrate 4 resonates during ultrasonic bonding or when the substrate 4 is thin, the resonance will be suppressed by the dummy pad 11. Therefore, it can be said that the embodiment shown in FIG. 4 holds the substrate more stably than the embodiment shown in FIG. Incidentally, dummy pads 12, 12, 12 indicated by broken lines in FIG. 4 may be arranged around the dummy pad 11. By using the dummy pad 11 having a certain area and the plurality of small dummy pads 12, 12, 12 in this way, a thick film circuit device that enables more reliable bonding can be obtained.

As described above, according to this invention, when an electronic component chip is bonded to the part of the other side of the board where the printed circuit is not provided, in cooperation with the part where the printed circuit is crossed over, A dummy pad is formed to prevent wobbling and has a thickness substantially equal to the area where the printed circuit crosses over, so the board does not wobble when bonding electronic component chips, allowing highly reliable bonding. A thick film circuit device is obtained.
Therefore, the thick film circuit device of this invention makes it possible to effectively prevent deterioration of chip components to be bonded.

[Brief explanation of drawings]

FIG. 1 is a plan view showing one surface of a thick film circuit device to which this invention is applied. FIG. 2 is a plan view showing a conventional thick film circuit device. FIG. 3 is a plan view showing an embodiment of this invention. FIG. 4 is a plan view showing another embodiment of this invention. In the figure, 1 and 2 are bonding parts, 3 is a crossover part, 4 is a substrate, 10, 11, 12
indicates a dummy pad.

Claims (1)

[Claims for Utility Model Registration] (1) A thick film circuit device comprising a bonding part for bonding an electronic component chip on one side of the board and a crossover part of the printed circuit on the other side of the board, The printed circuit is crossed over a portion of the other side where the printed circuit is not provided, which cooperates with the crossed over portion of the printed circuit to prevent wobbling of the board when bonding the electronic component chip. A thick film circuit device characterized in that a dummy pad is formed having a thickness substantially equal to that of the overlaid portion. (2) The thick film circuit device according to claim (1), wherein the dummy pad is formed in a region facing the bonding site across the substrate.