JPH01793A - Manufacturing method of circuit device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of wire bonding to a thick film conductor of a circuit board using a wire bonder having an image recognition function.

[Conventional technology and its problems]

In a thick film hybrid IC, a bonding pad made of a thick film conductor on a circuit board and an external lead are connected tangentially by a wire made of an AI wire or an Au wire. In order to perform this wire bonding, recently, automatic wire bonders that automatically determine the wire bonding position using an image recognition function and perform wire bonding are often used.

Image recognition in automatic wire honda generally handles binary image data, determines a predetermined position on a circuit board using a pattern matching method, and calculates a horning position from this position.

In pattern matching, analog image data taken from a TV camera is converted into binary image data, and compared with a preset standard pattern (binarized image data).
It is assumed that the predetermined position has been recognized when a predetermined matching rate (matching rate) is reached.

By the way, on a white Al203 (alumina) ceramic substrate, an Ag (silver) -Pd (palladium) based thick film conductor, an I(, LI02 (ruthenium oxide) based thick film resistor, and a glass film (insulator) were screened separately. TV is a standard thick film hybrid IC that is printed to form a thick film circuit.
When captured by the left camera, the conductor is the brightest, the ceramic substrate is darker than the conductor, and the resistor/glass film is darker than the ceramic substrate. Therefore, by converting the analog image data into binary image data by setting the binarization threshold so that the conductor becomes "white J" and the other "black J", the conductor pattern becomes "white" pattern. This is convenient for wire bonding to bonding pads that are part of the conductor. However, in reality, there is not a big difference in brightness between the conductor and the ceramic substrate, so if you set the threshold to ensure that the conductor becomes a "white J", some parts of the ceramic substrate that should become a "black J" will become irregular. "White J" is reversed. Ceramic substrate is more reliable "Black J"
When the threshold value is selected so that [a part of the conductor that should be white J] is irregularly inverted to white J. ,
Conventionally, it was not possible to obtain a high recognition rate.

Conventionally, it has been common practice to recognize images using the difference in brightness between a glass film or a resistor and a conductor in an analog image. Figure 6) shows a typical example.
A square glass film or resistor 2 is printed and fired on a ceramic substrate 1, and a cross-shaped conductor 3 is printed and fired on top of this.
It is fired to form a mark 4 exclusively for image recognition. conductor 3
For example, be sure to use [White J] against the glass film or the base of resistor 2.
It can be binarized as follows. Therefore, it is possible to perform image recognition (determination of the position of conductor 3) with a high recognition rate by using the cross-shaped "white J pattern" corresponding to conductor 3 as the characteristic figure of the pattern matching dog. However, before printing the conductor, Since printing the glass film or resistor 2 cannot be performed using a standard procedure, the steps of printing and firing the glass film or resistor 2 are added, leading to an increase in manufacturing costs.

The 6th square glass film or resistor 20 part is used as a conductor, and the cross-shaped conductor 3 part is used as a glass film or resistor, and the cross-shaped "black J pattern" corresponding to this glass film or resistor is image-recognized. In this case, the image recognition mark can be formed in the standard procedure of printing the glass film or resistor after printing the conductor, which requires additional printing and firing steps. However, since a glass film or resistor pattern is used for wire bonding to a bonding pad that is a part of the conductor, printing misalignment between conductor printing and glass film printing or resistance printing may occur. This will directly lead to a shift in the bonding position.Therefore, the bonding position accuracy will deteriorate.Furthermore, it will be necessary to secure a place to form the image recognition dedicated sign 4, so as the wiring pattern becomes denser, This may become a factor that inhibits densification and reduces the degree of freedom in pattern design.

Therefore, the purpose of the present invention is to form an image recognition area that has a high one-image recognition rate (low manufacturing cost, has little negative impact on pattern design, and can perform image recognition with high positional accuracy of the bonding position). The purpose is to perform wire bonding using

[Means for solving problems]

In order to solve the above problems and achieve the above objects, the present invention forms a thick film conductor on a ceramic substrate, and determines the wire bonding position for the thick film conductor based on image recognition using binary image data. a thick film having a first portion and a second portion facing each other with a spacing of about 0.35 mm or less; A conductor is provided on the ceramic board, and the approximately 0.55 mm
The area with the following intervals is used as the surface of the ceramic substrate for determining the reference position, and the surface of the ceramic substrate for determining the reference position? Extract the containing area using image recognition.

The present invention relates to a method of manufacturing a circuit device, characterized in that a wire bonding position is determined and wire bonded based on the position of the surface of the ceramic substrate for reference position determination obtained by this extraction.

[For production]

In image recognition, the ceramic substrate is darker than the conductor, but because it has a brightness close to that of the conductor, when binarizing the conductor as "white" and the ceramic substrate as "black J", it may be mistakenly marked as "white J". There is a risk that it will be recognized as such. However, in the vicinity of the conductor, the surface of the ceramic substrate is perceived as "black". For this reason, the @ sandwiched between the first and second parts according to the present invention
The surface of the ceramic board for determining the reference position is 0.35 mm or less.

It is almost certainly recognized as a ``black child'' and can serve as a highly reliable standard.

[First Embodiment] Next, a hybrid IC and a manufacturing method thereof according to an embodiment of the present invention will be described based on FIGS. 1 to 5. In FIG. 2 showing the completed hybrid IC, 1] is a support plate made of a Ni-coated Cu plate, 12 is a hole in the support plate 11, 13 is an external lead, 1.1 is a thick film circuit device, and 15 is a thick film circuit device. A protective resin made of silicone rubber that covers the membrane circuit device 11, 16 a power transistor chip, 17 a protective resin made of silicone resin, 18 to 23 wires made of A1 wire, 24 a sealing resin body made of epoxy resin, 25
is the mounting hole.

FIG. 3 shows a part of the thick film circuit device 14 of FIG. 2. As shown in FIG. The thick film circuit device 14 is formed by printing a conductive paste containing Ag-I'd powder and glass powder in a predetermined pattern on a ceramic substrate 31 whose main component is Al2O3, and then firing it. system thick film conductor 32,33% 34.35.36.37.38,
Furthermore, between the conductors 32 and 33,
It has 9. This thick film resistor 39 is covered with a protective glass film 40. Reference numeral 41 denotes a flip-chip type monolithic IC, which is face-down bonded to the ends of the conductors 33 to 38. Conductors 32 to 38, resistor 39.
and the glass film 40 are formed by screen printing and firing in this order. 32a.

Reference numerals 33a and 34a are bonding pads to which wires 18, 19, and 21 shown in FIG. 2 are ultrasonically wire bonded. Although not shown in the figure, there are of course also bonding pads for connecting the wires 20, 22, 23 of FIG. Wire bonding to the bonding pads 32a, 33a, and 34a is performed using an automatic wire bonder having an image recognition function. In order to perform this wire bonding easily and reliably, the pattern of the conductors 32, 33, 34% 35 in FIG. 3 is determined to have a special shape and size according to the present invention.

Partly, a narrow gap 11, j2 of 3.5 mm or less is provided between the conductor 32 and the conductor 33, and a narrow gap /4°15 of 3.5 mm or less is also generated between the cased conductor 34 and the conductor 35. There are parts. This narrow gap! 3.12
．． 14, how to use the j5 part will be explained in detail later.

FIG. 4 conceptually shows the configuration of an automatic wire bonder. This automatic wire bonder includes a bonding stage 60 on which a support plate 11 with a ceramic substrate 31 is placed, a push-opening device 61, a black and white TV right camera 2, a bonding tool 63, a moving mechanism 64, and an image reading device. It consists of a device 65 and a computer 66. The moving mechanism 64 supports a lighting device 61, a camera 62, and a tool 63, is movable relative to the stage t30, and moves to a target position under the control of a computer 66 accompanied by peripheral devices.

Next, the recognition of both images by the automatic wire bonder shown in FIG. 4 will be explained. First, the hybrid IC shown in FIG. 2 (however, wires 18 to 2
3. Set the protective resin 15.17 (without the sealing resin body 24).

The TV left camera 2 images a first area 42 shown surrounded by a dotted line in FIG. 3, which reliably includes the first reference point to be determined by percent image recognition according to a preset setting.

This analog image data is then sent to a 5-image reading device 65, where it is A-D converted into 256-level digital image data, and further binarized using a predetermined threshold value as binary image data. The data is input to the memory within the image reading device 65.

FIG. 1 schematically shows a binarized image 43 of the first area 42. Conductors 32 and 33 are almost certainly [white j
A threshold value is set so that the number of pixels is n. At this time, the area around the conductor 32 and 330 (up to a distance of about 0.15 mm) will almost certainly become a "black pixel (filled in black in the figure). The reason for this is not necessarily clear, but it is as follows. The conductor contains a glass component that strengthens its adhesion to the ceramic substrate.

Although this glass component is not visible to the naked eye,
It oozes out from the conductor to the periphery through printing and firing. The area where this glass component seeps out is due to the properties of the glass film, and if it is binarized, it will almost certainly become a "black J pixel" just like the glass film. The substrate 310 surface (shown as shaded) does not ensure a "black" pixel due to irregular surface reflections of light.

Irregularly "White J pixels are mixed in. The spacing between the bonding pad part 3.33 of the conductor 33 and the conductor 320 facing it is
/1=72=0.3mm, which is narrow. Therefore, the "2"-shaped ceramic substrate surface 44 exposed at the 1 interval/Ib/2 almost certainly becomes a "black" pixel. The first target single pattern 45 shown in FIG. 1 031 is preset in the memory of the computer 66 as binary image data for comparison. The computer 66 performs pixel calculations based on a predetermined procedure for pattern matching, and performs pixel calculations as shown in FIG.
4) Find a region 46 that matches the first standard pattern 45 from the binarized image 43 (when a region with a predetermined match rate or higher is found, it is considered to have matched). Region 46 includes the main portion of ceramic substrate surface 44 excluding the edges. In this way, the position Cx5y coordinates of the first reference point (for example, the center point of the region 46) of the conductor pattern on the bonding stage is accurately determined.

Next, by setting the TV camera 62 in advance, the second area 4 shown surrounded by a dotted line in FIG.
7 is captured, and the binarized image data is input into the memory of the image reading device 65 in the same manner as described above. FIG. 1(C) schematically shows a binarized image 48 of the second area 47.
It is the same as the prisoner in Figure 1. The laterally running portion of the conductor 34 is parallel to the conductor 35 at an interval of 13=0.45 mm. However, the protrusion gAs 35 a formed on the conductor 35
Therefore, it is located near the corner adjacent to the pounding pad 34a.

The part running in the horizontal direction of the conductor 34 is the conductor 35 and /4=0.3
They are narrowly sewn at mm intervals. Ponding pad 34
The distance between a and the conductor 350 is also narrowed to 15=0, 3 mm. Therefore, the "+:i]j-shaped ceramic substrate surface 49 exposed at 1 interval 14.15 almost certainly becomes 1 black J pixel. A second standard single pattern 50 is set in advance as binary image data for comparison shells.A region 51 that matches the second standard pattern 50 is found by pattern matching using a computer, as described above.

Region 51 includes the main portion of ceramic substrate surface 49 excluding the edges. In this way, the position of the second reference point (for example, the center point of region 51) of the conductor pattern on the bonding stage is accurately determined in the same manner as the first reference point.

1st. When the position of the second reference point is determined, it means that the position of the conductor pattern has been determined, and the center position of the bonding parameters (32a, 33a, 34a1 and others not shown) in the conductor pattern is determined in advance. It is calculated and determined relatively from the positional relationship in the pattern design,
This is input into the memory of the computer 66 as bonding position data. Further, the bonding position to the external lead 13 is calculated and determined relatively from the determined position of the conductor pattern, and is stored in the computer 66 as bonding position data. The accuracy is low due to variations in the bonding position to the external lead 13 and the position of the conductor pattern with respect to the support plate 11. However, the bonding pad portion of the external lead 13 is connected to the bonding pads 32ab, 33a, 34a in the conductor pattern.
Since the area is sufficiently large compared to the above, there is no problem in practical use.

Of course, the bonding position to the external lead 13 may also be determined by image recognition. In addition, the bonding position (two points) to the power transistor chip 16 is determined by image recognition using the chip pattern (details omitted),
The data is input into the memory of the computer 66 as bonding position data.

Once all bonding positions are determined in this way,
The computer 66 issues a command to perform a predetermined ultrasonic wire bonding operation while referring to the bonding position data, and as shown in FIG.
~23 bondings are performed.

For this automatic wire bonding? 0.35mm
The ceramic substrate surface 44°49 with the following width can almost certainly be made into a black pixel, and the conductor pattern can almost certainly be made into a white pixel. We were able to perform good wire bonding with a high image recognition rate without image recognition.Compared to the case where image recognition is not performed, the conductor pattern only requires slight changes, and printing and baking processes are added. There's nothing wrong with that.

Even if the H1 weight portion 35a is not formed and the entire portion of the conductor 34.35 running in parallel in the lateral direction is formed to have a width of /3-0.3 mm, image recognition of the region 51 can be performed well. . However, if the distance between the conductors is narrow and the distance between the conductors is long, short circuits between the conductors may occur, resulting in a decrease in manufacturing yield. Therefore 1 interval! ,,12.14.The length of the 150 portion should be kept to the minimum necessary. Practically speaking, conductors 33.
1 interval/, 12.14.
The lengths of the 15 parts are /, ~4/,, /2~4, respectively.
/2,! 4~4/<bls~415 i.e. 1~4 in each interval
A double range is desirable. Interval 'Ib' 2- '4-'
5 should not be made smaller than necessary ('1%'
2,/4.15) -0.2 to 0.35 mm.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIGS. 7 and 8. However, FIGS. 7 and 8 showing the second embodiment
In addition, FIGS. 9 and 10 showing a third embodiment, which will be described later,
Further, in FIGS. 11 and 12 showing modified examples, the first
Components that are substantially the same as those in FIGS.

The thick film circuit device 14a of the second embodiment shown in FIG.
Compared to the thick film circuit device 14 of the first embodiment shown in the figure, only the formation positions and patterns of the first and second reference position determining ceramic substrate surfaces 44a and 49a, which are made of non-printed areas of conductive paste, are different. ing. The surface 44a of the ceramic substrate for reference position determination in FIG. 7 is disposed in a cross shape within the wide portion of a single Ag-Pd wiring thick film conductor 320. The surface 44a of this reference position determination soil support board
Width 17 of the vertically extending portion and width 18 of the horizontally extending portion of
is approximately 0.3 mm, which is less than 0.35 mm. The vertically extending portion of the reference position determining ceramic substrate surface 44a is sandwiched between first and second portions made of thick film conductors, and the horizontally extending portion of the reference position determining ceramic substrate surface 4da is made of a thick film conductor. It is sandwiched between a third and a fourth part consisting of. The 16-width section between the first and second portions of the thick-film conductor functions identically to the 12-width section of FIG. The width 17 section functions in the same manner as the width 11 section in FIG. The second ceramic substrate surface 49a for reference position determination is also formed in a cross shape like the first ceramic substrate surface 4da for reference position determination, and has a portion extending in the vertical direction having a width I8 and a width 19. It consists of a part that extends in the horizontal direction.

It is provided in the wide portion of a single thick film conductor 35 for Ag--Pd wiring.

Image recognition by the automatic wire bonder in the thick film circuit device 14a shown in FIG. 7 is also performed in the same manner as in the first embodiment. That is, a binarized image 115a schematically shown in FIG. 8(4) is obtained by projecting the first region 42a shown surrounded by a square in FIG. 7 on a square camera. At this time, the thick film conductor 62 will surely become a "white J pixel, but the surface 4da of the ceramic substrate for reference position determination, which consists of the non-printed part of the conductor paste where @+s, +7 is 0.3 mm, will become a "black" pixel. . Therefore, Figure 8C
Area 4 that matches the first standard pattern 115a shown in B)
6a and determine the first reference point. Next, the second area 47a is also captured on the camera in the same way as shown in FIG.
) A VC binarized image 48a is obtained. At this time, the second cross-shaped
The surface 49a of the ceramic board for determining the reference position becomes the "black pixel. Therefore, the second standard pattern 5 shown in FIG.
A region 48a that matches 0a is found and a first reference point is determined. Note that the wire bonding in the second embodiment is performed on the ceramic substrate surface 44a for reference position determination;
The second embodiment is carried out in the same manner as the first embodiment except for the difference in the shape and formation position of 49a. Therefore, the second embodiment has the same operation and effect as the first embodiment.

In the second embodiment, a non-printing area of conductor paste is provided in one thick film conductor 62, 65 for wiring to serve as the surfaces 44a and 49a of the Yaramic board for determining the reference position.
It is no longer necessary to narrow the distance between the thick film conductors for wiring as in the embodiment described above, and there is no risk of lowering the withstand voltage between the thick film conductors for wiring.

Note that the ceramic substrate surfaces 44a and 49 for determining the reference position
Since the current can be passed through the portion surrounding a, the circuit device does not become very large by providing the reference position determining ceramic substrate surfaces 44a, d9a in the wiring thick film conductor 32.35.

[Sixth Embodiment] FIGS. 9 and 10 show a third embodiment of the present invention. This third embodiment is based on the ceramic substrate surface d for reference position determination.
This embodiment is the same as the second embodiment except that 4b and 49b are L-shaped. In this sixth embodiment, the ceramic substrate surfaces 44b and 49b for reference position determination have a width of 110.Ill.112.11 within the thick film conductor 32.35.
3. 110~1]3 is set to 0.30mm below 0.35mrrlJ, so the first and second regions 42b and 47b are
When one image captured by a television camera is recognized in the same manner as in the embodiment, binarized images 45b and 48b schematically shown in FIG. 10 (At(C)) are obtained.
13 is a "black" pixel. Therefore, regions 46b and 51b corresponding to the first and second standard patterns 45b and 50bvc shown at Ω in FIG. 10 are found, and the first and second reference points are determined in the same manner as in the first embodiment.

[Modified example]

The invention is not limited to the embodiments described above.

For example, the following transformations are possible.

(1) As shown in Fig. 11, it consists of a conductor paste non-printing area of 0.35 mm or less @1 extending only in the vertical direction (one direction) in the wiring thick film conductor 62 on the oak ε ivy board 31. A ceramic substrate surface 44c for determining a reference position may be provided. In this case, a standard pattern corresponding to the area surrounded by dotted lines is prepared.

(2) Bonding pad 32a of thick film conductor 62 for wiring and bonding bath 3 of thick film conductor 33 shown in FIG.
3a may be provided with a reference position determining ceramic substrate surface 44d consisting of a conductor paste non-printing area ρ having a width l of 0.35 mm or less and extending only in one direction. In this case as well, a standard pattern corresponding to the portion surrounded by the dotted line is prepared.

f3+ 16-113 and 1 also 0.2-0.35mm
In order to clearly obtain a reference pattern, it is preferable to set the value within the range of .

(41 A thick film conductor unrelated to electrical connection is provided opposite the thick film conductor for wiring, and a conductor paste non-printing area with a width of 0.35 mm or less is provided between them, and this is set on the surface of the ceramic substrate for reference position determination. May be used as

〔Effect of the invention〕

As is clear from the above, the present invention has the following effects: (11) good image recognition (high image recognition rate) comparable to the conventional case of forming a dedicated image recognition mark made of a conductor on a glass film or resistor; and high bonding position accuracy).

(2) It is no longer necessary to form a thick film dedicated to image recognition through printing and baking processes, making it possible to reduce the cost of a single-circuit device.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing the image recognition pattern according to the embodiment of the present invention, where 0 indicates the first area, ■ indicates the first standard pattern, and 0 indicates the second area. Show - ([
1 is a diagram showing the second standard pattern, and FIG. 2 is a plan view showing the hybrid IC. FIG. 6 is a plan view showing a part of the thick film circuit device. FIG. 4 is a block diagram schematically showing an automatic wire bonder. FIG. 5 is a plan view showing the thick film circuit device after wire bonding. The sixth drawing is a plan view showing a conventional sign exclusively for image recognition, and FIG. 6) is a cross-sectional view taken along the line BB of the sign in the sixth drawing. FIG. 7 is a plan view showing a part of the thick film circuit device of the second embodiment. FIG. 8 schematically shows an image recognition pattern in the second embodiment corresponding to FIG. 1, and FIG. 9 is a plan view showing a part of the thick film circuit device of the sixth embodiment. FIG. 10 is a diagram schematically showing an image recognition pattern in the third embodiment, corresponding to FIG. 1. FIGS. 11 and 12 are plan views showing a portion of a modified thick film circuit device. 61... Yarabikku substrate, 32-38... Thick film conductor. 42... First region, 44... Ceramic substrate surface for reference position determination, 45... First standard pattern. Agent Nori Takano Figure 3 Figure 5 Figure 6 Figure 7 Figure 10

Claims (1)

[Claims] (1) A circuit including forming a thick film conductor on a ceramic substrate, determining a wire bonding position for the thick film conductor based on image recognition using binary image data, and bonding a wire to the wire bonding position. In a method of manufacturing a device, a thick film conductor having a first portion and a second portion facing each other with a spacing of about 0.35 mm or less is provided on a ceramic substrate;
A region having an interval of 1 m or less is used as the surface of the ceramic substrate for reference position determination, a region including the surface of the ceramic substrate for reference position determination is extracted by image recognition, and the ceramic for reference position determination obtained by this extraction is A method for manufacturing a circuit device, comprising determining a wire bonding position based on a position on a substrate surface and performing wire bonding.