JPH0226383B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for calculating hole positions in a ceramic sintered substrate that has holes through which lead wires of electronic components can be inserted and can be used as a circuit wiring board.

Such ceramic sintered substrates, such as alumina substrates, are usually manufactured by punching a number of predetermined holes into a green sheet and then sintering it at high temperature. Wiring conductors are printed, lead wires of electronic components are inserted into predetermined holes, and then soldered to the wiring conductors.

When the above green sheet is sintered at high temperature, the binder, air, etc. are scattered and the substrate is reduced by about 10% to 20%.
The shrinkage rate varies widely from lot to lot. Therefore, the position of the hole (distance from the edge of the board to the hole) created in the green sheet changes due to sintering, making automatic insertion of electronic components with lead wires difficult. Since most of the board dimensions were about 2 inches square, the degree of change in the hole position was small and fell within the tolerance range of the automatic insertion machine, so it did not cause any major problems.

However, recently, some alumina substrates have relatively large dimensions depending on the intended use or because they are easier to handle with automatic insertion machines.
In order to match the PCB, a large board size of, for example, 6 inches square may be required. In this case, the position of the hole on the board deviates by a large amount from the set value, and the variation becomes so great that it falls outside the tolerance range of the automatic insertion machine, making it impossible to automatically insert parts, making it difficult to increase the size of the board. It was hot.

Although it is also possible to use an automatic insertion machine that can correct the hole position, it takes too much time and is insufficient in terms of cost.

Therefore, an object of the present invention is to provide a hole position calculation method for a ceramic sintered substrate that can be applied to an automatic insertion machine even if the dimensional tolerance of the substrate (hole position) varies as the size of the substrate increases. .

Embodiments of the present invention will be described in detail below with reference to the drawings.

1A shows a green sheet 1 of an alumina substrate which is a ceramic sintered body substrate, and FIG. 1B shows an alumina substrate 2 after sintering. As shown in FIG.
At the same time as forming the marks 3, . The positions of the marks 4 and the holes 3 are set at predetermined distances X ₀ , Y ₀ , X ₁ , Y ₁ in the x direction and the y direction from a corner connected by two substrate edges, for example, a reference point A. When the green sheet 1 provided with the holes 3 and marks 4 is sintered at high temperature, the substrate shrinks and the marks 4 are formed as shown in FIG.
The position changes to X ₀ ′, Y ₀ ′. Further, the positions of the large number of holes 3 also change depending on the position of each hole 3.

A predetermined conductive pattern is applied to the alumina substrate 2 provided with such holes 3 and marks 4, and various electronic components are mounted.
The position of the mark 4 is calculated from the reference point A, the relative positional deviation of each hole 3 is calculated, and the position where the part is inserted is corrected based on this calculated value, and the part is inserted automatically. For example, by deriving α=X ₀ ′/X ₀ , β=Y ₀ ′/Y ₀ (these fractions are called the shrinkage ratio of the green sheet), we get X ₁ ′=αX ₁ , Y ₁ ′=βY ₁ , ...Xn′=αXn,
Find Yn′=βYn and insert the parts.

According to this method of calculating the hole positions of a ceramic sintered substrate, even if the dimensional tolerance of the large alumina substrate (hole positions) varies, it can be easily and reliably inserted into an automatic insertion machine.

In the embodiment described above, two or more marks 4 may be provided on the substrate, and in this case, the deviation in the rotational direction of the substrate can also be corrected. Further, the mark according to the present invention may be formed by using any predetermined hole among a large number of holes. Further, regarding the method of calculating the hole position, in the example, the shrinkage rate of the green sheet was calculated in two directions, the x direction and the y direction, but the method is not limited to this example.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of a ceramic sintered body substrate according to the present invention. 1 is a green sheet, 2 is a ceramic sintered body,
3 is a hole, 4 is a mark.

Claims (1)

[Scope of Claims] 1. A method for calculating hole positions in a ceramic sintered substrate formed by sintering a green sheet in which a hole through which a lead wire of an electronic component can be inserted is formed at a position a predetermined distance from the edge. A mark is formed in advance at a predetermined distance from the edge of the green sheet, and the green is determined from the position of this mark and the position of the mark on the ceramic sintered substrate after sintering this green sheet. Find a formula that represents the product of the shrinkage rate of the sheet (expressed as a fraction) and the distance from the edge of the hole position of the green sheet, and use this formula to calculate the hole position of the ceramic sintered substrate. A method for calculating hole positions in a ceramic sintered substrate, characterized by: