JPH05235556A - Pattern cut structure of thin film substrate - Google Patents

Abstract

PURPOSE:To realize a pattern cut without relation to quantity of energy of laser beam on the occaion of cutting a pattern of a thin film substrate on whose surface a patterned insulating layer is formed. CONSTITUTION:In a pattern cut constitution of a thin film substrate having a multilayer insulating layer 2 on the surface thereof and a pattern 10 formed on the surface of the insulating layer 2 cut as required with a laser beam, a dummy pattern 4 ensuring higher reflectivity of laser beam or high absorption coefficient is formed, corresponding to the forming position of the pattern 10, at a lower layer L2 of the layer L3 forming the pattern 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern cut structure of a thin film substrate, and more particularly to a thin film substrate in which a multilayer insulating layer having a pattern for each layer is formed on a substrate such as ceramics.
Design change of the pattern formed on the surface layer of the insulating layer,
The present invention also relates to a pattern cut structure of a thin film substrate that is cut by using a laser beam for repair or the like.

In recent years, as computers have become faster,
The circuit boards used for this are becoming more and more dense, and the board materials have changed from glass epoxy and phenol resin boards to polyimide thin film boards.

On the other hand, when it is necessary to change the wiring for a reason such as a design change or repair of the once formed wiring pattern, the previous pattern is cut and a new pattern is formed by newly connecting with a wire or the like. Is done.

Pattern cuts on substrates with strong mechanical strength, such as glass epoxy and phenol resin plates, were easy to cut mechanically with a drill or cut knife, but polyimide thin film substrates used as thin film substrates. Since the part where the pattern is formed is thin and soft, the mechanical cutting method cannot be used.

For this reason, it is practiced to irradiate a portion to be cut with laser light and cut the pattern with this laser light.

[0006]

2. Description of the Related Art Conventionally, as shown in FIG. 4, insulating layers 41 and 43 which are patterned (patterns 45 and 42) for each layer are formed on the surface of a substrate 40 made of ceramic or the like. , 43, the pattern 45 having the solder 44 formed on the surface layer 43 needs to be cut, the cut portion A is irradiated with laser light to cut the cut portion A.

[0007]

However, when the cut portion A is cut in the prior art, no processing is applied to the underlying layer, and it is difficult to appropriately adjust the energy amount of the laser light. As shown in FIG. 5, when the amount of energy of laser light is large, the pattern formed in the lower layer and even the lower layer may be cut (shown in FIG. 5C).

On the other hand, if the amount of energy is too small, the pattern to be cut cannot be completely cut, and there is a risk of wiring abnormality (shown in FIG. 5B).

Therefore, according to the present invention, when the pattern of the thin film substrate having the patterned insulating layer formed on the surface of the substrate is cut, the pattern cutting is performed without being influenced by the energy amount of the laser beam. The purpose is to do.

[0010]

The above object is to provide a thin film substrate having a multi-layered insulating layer 2 on its surface and cutting a pattern 10 formed on the surface of the insulating layer 2 with laser light as necessary. In the pattern cut structure of
The pattern 10 is formed on the lower layer L2 of the layer L3 in which 0 is formed.
The pattern cut structure of the thin film substrate is characterized in that the dummy pattern 4 having a high reflectance or an absorptance of the laser beam is formed corresponding to the formation position.

[0011]

That is, according to the present invention, since a dummy pattern having a high reflectance or an absorptance of the laser beam is formed at a corresponding position in the lower layer of the pattern to be cut, the energy amount of the laser beam is increased. However, the laser light will not further cut the dummy pattern to the lower layer pattern and the lower insulating layer.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing the operation of the present invention. FIG. 3 is a diagram showing another embodiment of the present invention. The same reference numerals in FIGS. 1 to 3 denote the same objects.

As shown in FIG. 1, a thin film substrate is formed by forming an insulating layer 2 patterned for each layer on the surface of a substrate such as ceramics. The insulating layer 2 has a first layer L1. Is partially connected to the inner layer pattern 3, the second layer L2 is partially connected to a dummy pattern for reflecting or absorbing laser light, and the third layer (surface layer) L3 is connected to the pad 5 and the pad 5 thereof. Each pattern 10 is formed. Solder 7 for connecting input / output terminals (not shown) is applied onto the pad 5.

Although not shown, the pad 5, pattern 10 formed on the third layer L3 and the inner layer pattern 3 formed on the first layer L1 are connected to the wiring in the substrate by a via or the like. There is.

Now, a change occurs in the pattern of the third layer L3,
When it becomes necessary to perform pattern cutting, the cutting portion 6 (hatched portion) in FIG. 1 is cut by laser light. Lower layer (L2) of the pattern 10 (cut portion 6) to be cut at this time
Has a dummy pattern 4 formed at least in its cut portion, and the dummy pattern 4 prevents the energy of the laser light from reaching the inner layer pattern 3 and the first layer L1 any more (reference numeral in FIG. 2). 8).

By providing the dummy pattern 4 in this way, it has been necessary to control the laser light during cutting so that it does not reach more than necessary, but the energy control can be roughened. ..

The dummy pattern may be a partial pattern or may be a solid layer over the entire second layer L2. In particular, as shown in FIG. 3, a ground (GND) layer or a signal layer 9 is always provided in the insulating layer 2, and the ground (GND) layer or the signal layer 9 is solid-printed on the entire layer. Since it is configured, this ground (GND) layer or signal layer 9
Is also effective as a dummy pattern. Even if the ground (GND) layer or the signal layer 9 is used as a dummy pattern, there is no particular problem as long as a via or the like for connecting the layers is provided.

[0019]

As described above, according to the present invention, the pattern cutting of the thin film substrate can be realized with high quality, which greatly contributes to the invention.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an operation of the present invention.

FIG. 3 is a diagram showing another embodiment of the present invention.

FIG. 4 is a diagram showing a conventional example.

FIG. 5 is a diagram showing a problem.

[Explanation of symbols]

 1 thin film substrate, 2 insulating layer, 3 inner layer pattern, 4 dummy pattern, 5 pads, 6 cut parts, 9 ground (GND) layer or signal layer,

Claims (2)

[Claims] 1. A multi-layer insulation layer (2) is provided on the surface of the layer,
In a pattern cut structure of a thin film substrate, which cuts a pattern (10) formed on the surface of the insulating layer (2) with a laser beam as needed, a lower layer of a layer (L3) on which the pattern (10) is formed. A pattern cut structure for a thin film substrate, characterized in that a dummy pattern (4) having a high reflectance or an absorptance of a laser beam is formed in (L2) corresponding to the formation position of the pattern (10). 2. The pattern cut structure for a thin film substrate according to claim 1, wherein the dummy pattern (4) is either a ground pattern or a signal pattern.