CN1753601A - Method for manufacturing components with printed circuits - Google Patents

Abstract

The invention relates to a method for producing a component with a printed circuit (24): a printing template (3) with a lower product layer (4) and at least one grid layer (5) thereon is placed On the substrate surface (1), the product layer has at least one lower opening (6) and the grid layer has at least one upper opening (7) arranged above it, in which an intermediate material region ( 10), which extend through the upper opening and partially cover the lower opening. The paste is printed onto the substrate surface by means of a printing stencil and the printing stencil is removed, wherein the areas of material (18, 20) printed through the openings (6, 7) remain on the substrate surface and harden to A circuit area within a circuit on the surface of a substrate. After removal of the printing stencil, homogenization of the material areas advantageously takes place, so that material areas of different thicknesses can be formed in one step of the stencil printing process.

Description

Method for manufacturing components with printed circuits

technical field

The invention relates to a method for producing a component with a printed circuit, wherein the component can be used in particular in automotive electronics.

Background technique

Substrates for electronic circuits in automotive electronics are produced, inter alia, using thick-film technology and low-temperature co-fired ceramic (LTCC) technology. Here, electronic conductor tracks and other functional elements, such as resistors, for example, are produced using screen printing technology. In screen printing technology, a thick-film paste is scraped or printed through openings in the screen or stencil onto a printing substrate. Ceramic wet films (Grünfolien) or already sintered ceramic substrates can be used as printing substrates. A sintered solid structure is produced from the thick film paste in a subsequent firing or sintering step.

In conventional screen or stencil printing techniques, the thickness of the applied layer of the material to be structured is determined by the thickness of the screen or stencil. The screens or stencils used here have a flat surface, so that the scraping or printing process is not disturbed. In addition, the side facing the substrate is also generally smooth and flat in order to obtain a sufficient seal to the substrate so that the paste does not spread and the desired printed pattern is precisely formed.

In screen and stencil printing processes, generally with constant properties per unit area of the material to be printed, different properties of printed structures are achieved by correspondingly varying transverse widths at uniform thicknesses. In order to form conductor tracks for higher currents, for example for connecting an output stage to a valve control or the like, compared to simple signal lines, significantly wider structures are therefore formed which require a corresponding one on the substrate. The area, which will lead to an increase in cost, and the unfavorable area needs to be expanded. Correspondingly, different R values (resistance values) are produced, for example, from R-paste.

Furthermore, in screen and stencil printing, the aspect ratio (Aspektverhltnis), ie the ratio of the transverse dimension of the opening in the screen or stencil to the thickness, is of great importance. Microstructures in the range of, for example, 20 μm cannot be produced with arbitrary thicknesses. Generally, fine resolution (Auflsung) requires a small printing thickness due to paste rheology and paste flow properties. Due to increasing miniaturization, ever finer structures have to be produced on electronic substrates, which can only be produced with very small layer thicknesses using conventional screen or stencil printing techniques. However, it is also necessary to be able to realize conductor tracks and structures in the substrate which have a higher current-carrying capacity than simple signal lines. Therefore, it is again necessary to construct a wider structure. In order to form different microstructures, it is known to produce the different structured regions in successive printing processes using conventional screen printing techniques.

In addition, pastes of different properties can be applied. In addition to metallic structures, insulating or ceramic and semiconducting structures can also be coated, for example produced by resistor paste. In order to tune the resistor to its specific value, on the one hand various resistor pastes with different resistance values per unit area are used, for example 100 ohms or 1, 10, 100 kohms per unit area, and on the other hand fine tuning is achieved by area tuning. The print thickness is constant here.

In order to avoid widened structures, gravure printing is used in some cases, in which printed structures with different thicknesses are formed. In this case, a shape corresponding to the printed pattern is first formed or scratched out on an intaglio printing plate. Then, in a second step, the intaglio printing plate is turned over and transferred onto the substrate, or the substrate is correspondingly turned over and placed on the intaglio printing plate. Compared to conventional screen printing, this requires an additional process step and thus a longer cycle time. In addition, these gravure plates are expensive and expensive to manufacture.

Contents of the invention

The invention proposes a method for producing components with printed circuits, comprising at least the following steps: a printing template having a lower product layer and at least one grid layer arranged on the lower product layer is placed on On the substrate surface of a substrate, wherein the product layer has at least one lower opening and the grid layer has at least one upper opening arranged above the lower opening in which the intermediate material is formed Areas, which extend through the openings of the upper part and partially cover the openings of the lower part, the material paste is printed on the substrate surface through the printing stencil and the printing stencil is removed, wherein the printed stencil remains on the substrate surface through these openings regions of material, and these regions of material harden into circuit regions of a circuit on the surface of the substrate.

The method of the invention has several advantages. According to the invention, a printing template is used which has a lower product layer and at least one upper grid layer arranged thereon. In a known manner, the product layer defines, by its openings, the areas to be printed. The grid layer has upper openings which can be substantially coincident or aligned with the lower openings of the product layer, or which can also be larger than these lower openings. In this case, the intermediate material region extends in the upper opening of the grid layer, in particular web structures, such as parallel webs, which divide the upper opening into opening regions or sub-openings. In this way, the lower openings of the product layer are partially covered by the intermediate material regions of the upper openings located above them, so that the overall open area of the formed through-holes is reduced.

During printing, no material paste is applied in the intermediate material area, so the average vertical thickness of each applied material area is reduced by a factor as the ratio of the total open area of the upper opening to the open opening area The area share of the area of the lower opening.

In order to form structures with a substantially uniform vertical thickness, after printing the material paste and removing the template, homogenization (Vergleichmssigung) of the applied structure is achieved in that the material paste due to its flow properties is at least substantially Upper equalizes the microstructure in the current material region. The inherent viscous properties of the material paste are sufficient here. Auxiliary measures to accelerate or support the flow properties can be used, such as irradiation with ultraviolet radiation, or in principle also other media can be added, such as softeners or solvents.

After the homogenization of the vertical thickness of the individual material regions, the material regions pasted with the applied material are hardened in a known manner by, for example, a sintering process.

It is advantageous if the intermediate material regions passing through these upper openings form microstructures in the material regions which at least partly flow away after the printing stencil has been removed and before the material regions harden.

Advantageously, the grid layer has a plurality of upper openings with intermediate material regions.

Advantageously, these intermediate material regions are grid-like web structures.

Advantageously, the grid-like web structure surrounds a rectangular, preferably square, opening area.

It is advantageous if, in the various openings, a grid-like web structure is formed with different webs arranged in parallel at adjacent distances from one another.

Advantageously, metallic, ceramic, semiconductor or polymeric components are formed from these material regions.

An advantage of the invention is that, unlike conventional stencil or screen printing techniques, it is possible to apply current-carrying and fine conductor tracks of an electronic circuit with different thicknesses in one printing step. This always results in better area utilization. Furthermore, the resistance value of printed resistors can be adjusted not only by using different material-dependent resistance values or paste properties, or by adapting the lateral area, but also by different thicknesses. In this way, the area utilization of the structure can be improved and the variation of the different resistor pastes used can be reduced, thus enabling the area-optimized use of a small number of different resistor values with fewer printing steps, thus advantageous in terms of time and cost.

Compared to the use of gravure printing plates, the simplified processing sequence, which requires only one printing step, has the advantage.

According to the invention, a plurality of grid layers can also be placed on the product layer in principle. Furthermore, several printing steps using different materials can also be used according to the invention, wherein the number of printing steps can be reduced compared to conventional methods. In this way, for example, conductor tracks can be printed in one printing step and different resistors can be printed in another printing step. In addition, for example semiconductor material can be printed in a further printing step.

Description of drawings

The invention will be described in detail below with the aid of the attached illustrations of several embodiments. The picture shows:

Fig. 1 is a cross-section of a printing template with a product layer and a grid layer of the present invention;

Figure 2 is a top view of the product layer and grid layer in Figure 1;

Fig. 3 Different structures in the grid layer, with

a) completely open area;

b) The reduced area share x1 and

c) The reduced area share x2<x1;

4a, b Cross-section in a method step after removal of the printing template, and cross-section of a construction element according to the invention after homogenization and hardening of the material paste.

Detailed ways

In an inventive printing method, a printing template 3 according to the invention is placed on the substrate surface 1 of a substrate 2, the printing template having a lower product layer 4 and at least one upper grid layer 5 .

The product layer 4 has a thickness d1 and penetrating lower openings 6 for forming corresponding structures on the substrate surface 1 . The grid layer 5 placed on the product layer 4 has a thickness d2 and upper openings 7 , which advantageously essentially correspond to or fit over the lower openings 6 of the product layer 4 on the outer contour. Alternatively, in principle, the upper opening 7 can also be designed slightly larger than the lower opening 6 . Intermediate material regions 10 extend through these upper openings 7 , which in the exemplary embodiment are designed as web structures 10 with individual webs 12 . Here, the webs 12 can, for example, run parallel and/or cross one another. The respective upper opening 7 is divided by the webs 12 into individual opening regions 14 . In the web structures 10 shown in FIGS. 2 and 3 , they each have the shape of a rectangular grid forming regularly arranged square opening regions 14 . The overall area of the opening region 14 formed in the upper opening 7 is therefore smaller than or equal to the open area of the upper opening 7 in question, as can be seen in particular in FIGS. 3 a to c.

Figure 3a shows a grid layer 5 without intermediate material and tab structure 10, that is to say, the ratio xa of the total open area F7 of the opening 14 to the open area F6 of the lower opening 6 is xa=F7 /F6=1. In FIG. 3 b correspondingly, a reduced area fraction xb<1 results, since the web structure 10 partially covers or limits the area of the lower opening 6 . In FIG. 3c, the webs 12 of the web structure 10 are arranged closer together, so that the area fraction xc<xb.

According to the invention, in a stencil printing process, the material paste 16 is printed onto the substrate surface 1 through the openings 6 and 7, so that after removing the printing stencil 3, firstly the corresponding grid layer 5 shown in FIG. 4a is obtained. . A structure having a material paste of thickness d1+d2. The material paste 16 then flows away in such a way that these material regions are flattened and thus form a first material region 18 of greater thickness and a second material region 20 of smaller thickness. Here, in each material region 18 , 20 , the current overall thickness di is related to the area fraction xi as di=d1+xi*d2. The material paste 16 of the material regions 18, 20 then hardens in a known manner, thus forming a part 22 shown in FIG. made circuit 24. The material regions 18 , 20 can be, for example, conductors, semiconductor components or ceramic components.

Claims (9)

1. one kind is used for the method that manufacturing has the parts of printed circuit (24), has following steps at least:

With a gas producing formation with a bottom, (4) and at least one be arranged on grid layer on the gas producing formation of bottom, (5) printing stencil, (3) be placed on a substrate, (2) substrate surface, (1) on, wherein, described gas producing formation, (4) has the opening of at least one bottom, (6), and this grid layer, (5) has the opening that at least one is arranged on the bottom, (6) opening on Shang Fang top, (7), in the opening on top, constructed the intermediate materials zone, (10), they extend through the opening on top, (7) and with the opening of bottom, (6) partly hide

By printing stencil (3) material cream is stuck with paste (16) and be printed onto substrate surface (1) and go up and take printing stencil (3) away, wherein be retained in substrate surface (1) and go up by these openings (6,7) typographic material areas (18,20), and

These material areas (18,20) are hardened to the circuit region of the circuit (24) on substrate surface (1).

2. in accordance with the method for claim 1, it is characterized in that: the intermediate materials zone (10) of the opening (7) by these tops is at described material area (18,20) constitute fine structure (19 in, 21), they are taking down printing stencil (3) back and were scattering at least in part before described material area (18,20) sclerosis.

3. it is characterized by in accordance with the method for claim 2: described material cream stick with paste (16) structure the material area (18,20) of fine structure (19,21) at the described vertical thickness di that has after wandering be:

di＝d1+xi*d2，

Wherein d1 is the thickness of gas producing formation (4), d2 is the thickness of grid layer (5), xi is an area fraction, and this area fraction is by the open area of the opening (6) of bottom and be positioned at composition of proportions between the gross area of the open area of opening wide (14) of opening (7) on top of opening (6) top of bottom.

4. according to one of aforesaid right requirement described method, it is characterized by: this grid layer (5) has a plurality of openings (7) that have the top in some intermediate materials zones (10).

5. according to one of aforesaid right requirement described method, it is characterized by: these intermediate materials zones (10) are grid-like tab construction (10).

6. it is characterized by in accordance with the method for claim 5: described grid-like tab construction (10) be surrounded as rectangle, square open area (14) preferably.

7. in accordance with the method for claim 6, it is characterized by: in these different openings (7), constructed some and had the grid-like tab construction (10) of the contact pin (12) of the different parallel placements of spacing located adjacent one another.

8. according to one of aforesaid right requirement described method, it is characterized by: the parts that constitute metal, pottery, semi-conductive or polymer by these material areas (18,20).

9. according to one of aforesaid right requirement described method, it is characterized by: in a plurality of steps, be coated with the material cream that applies different qualities respectively and stick with paste (16).

Images