Method for manufacturing multilayer circuit boards

Abstract

The present invention relates to a method for manufacturing a multilayer circuit board. First, within the scope of the assembly method steps, multiple functional layers (5) and at least one insulating layer (4) of the circuit board to be manufactured are arranged layer by layer between a lower mold (2) and an upper mold (1) of a multi-part mold, and at least one measuring value encoder is positioned between the upper mold (1) and the lower mold (2) such that the measuring value encoder is abutting against at least one functional layer (5) and / or insulating layer (4) of the circuit board to be manufactured. Then, within the scope of the assembly method steps, the mold together with the multiple functional layers (5), the at least one insulating layer (4) and the measuring value encoder are loaded into a thermal compression cavity (20). Then, further within the scope of the manufacturing method steps, the upper mold (1) and the lower mold (2) together with the multiple functional layers (5) and the at least one insulating layer (4) disposed therebetween and the measuring value encoder are pressed and heated against each other in the thermal compression cavity (20), and the measuring value encoder is used to detect the measuring value. Here, the measured values ​​and / or the data obtained therefrom are transmitted to the manufacturing control device (13) during the ongoing manufacturing method steps, and the manufacturing control device (13) processes the measured values ​​and / or the data obtained therefrom with reference to predetermined values ​​of the measurement parameters for the measured value encoder, for monitoring the ongoing manufacturing method steps and / or for controlling the ongoing manufacturing method steps.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a multilayer circuit board. First, within the scope of an assembly method step, multiple functional layers and at least one insulating layer of the circuit board to be manufactured are arranged layer by layer between a lower and upper mold of a multi-part mold. At least one measurement encoder is positioned between an upper and lower portion of the mold frame such that the measurement encoder abuts against at least one functional layer and / or insulating layer of the circuit board to be manufactured. Then, within the scope of an assembly method step, the mold, along with the multiple functional layers, the at least one insulating layer, and the measurement encoder, is inserted into a thermocompression chamber. Further, within the scope of a manufacturing method step, the upper and lower molds, along with the multiple functional layers and the at least one insulating layer disposed therebetween, and the measurement encoder, are pressed together and heated in the thermocompression chamber, where the measurement encoder is used to detect measured values. Background Technology

[0002] Multilayer circuit boards are now typically manufactured in a layered hot press. Within the scope of experimental testing of this manufacturing method, suitable process parameters for operating the layered heating device are determined, and subsequent assembly is performed using these experimentally determined process parameters. To determine the parameters necessary for the experimental testing, functional layers, particularly copper-based layers, and insulating layers are alternately stacked in the mold during the assembly process steps. Between these two layers, a temperature sensor is positioned as a measuring encoder, and a signal line is led out from the mold. Here, the temperature sensor constitutes a lost sensor that cannot be reused.

[0003] The free ends of the signal lines are typically temporarily fixed to the outside of the mold, for example, by means of adhesive strips. The assembled mold is then loaded into a stacking hot press along with several other molds in the assembly process step. Here, the lower mold is placed on and oriented or positioned relative to the heating plate of the stacking hot press. The heating plate serves as a support for the mold. The upper mold is spaced apart from another heating plate positioned above it, which (except for the uppermost heating plate) supports another assembled mold.

[0004] To allow for the determination of measured values ​​and method parameters in experimental testing, the free end of the signal line is detached from the corresponding mold and connected to a data storage box, which is positioned within the hot compression chamber of a layered hot press along with the heating plate and the mold. The hot compression chamber is then sealed, and the heating plates are moved relative to each other in subsequent manufacturing steps, such that the mold is sandwiched between the two heating plates and heated by the equipped mold, bonding the functional and insulating layers under pressure within the mold. During this forming process, the temperature inside the mold is measured, particularly by means of a temperature sensor.

[0005] The determination of process parameters is carried out offline within the scope of the experimental tests. During the experimental tests, only data is detected and collected in a data storage box. Data preparation and evaluation are performed subsequently. Therefore, the measurements determined during the experimental tests are not used to control or regulate interventions in the ongoing manufacturing process steps. Furthermore, the manual cabling of individual temperature sensors in the hot lamination press is costly, time-consuming, and carries a risk of burns to the machine operator due to the limited space available and the typical 100°C or higher temperatures predominant there.

[0006] In exceptional cases, the methods described above for experimental testing can also be applied to the mass production of circuit boards. However, due to the high time consumption and associated high costs, this is only done in exceptional circumstances, such as when the circuit board to be manufactured is used in a safety-critical application and therefore the user has specific requirements for monitoring and recording of the manufacturing process. Even in such cases, it is not feasible to use the measured values ​​for online intervention in the ongoing manufacturing process steps. Summary of the Invention

[0007] The objective of this invention is to provide an improved method for manufacturing multilayer circuit boards.

[0008] To address the aforementioned task, the present invention is characterized in that the measured values ​​and / or the data obtained therefrom are transmitted to a manufacturing control device during the ongoing manufacturing method steps, and the manufacturing control device processes the measured values ​​and / or the data obtained therefrom with reference to predetermined values ​​of measurement parameters for the measured value encoder, for monitoring the ongoing manufacturing method steps and / or for controlling the ongoing manufacturing method steps.

[0009] A particular advantage of this invention is that it allows for intervention in ongoing manufacturing process steps through online detection and processing of measured values. The manufacturing process steps can be monitored and readjusted by referring to relevant process parameters, such as the temperature in the hot compression chamber or mold and / or the pressure applied to the mold. This allows for optimized processes and, if necessary, earlier process termination than planned. Consequently, process time or cycle time is reduced, and production volume can be increased. Higher production volume then directly leads to lower costs or an increase in the number of parts manufactured.

[0010] Furthermore, quality control can be established by monitoring improvements to ongoing manufacturing process steps, allowing for the identification of defects in the manufacturing process before the manufactured circuit boards are supplied and reach the market. This improves product quality and reduces the costs associated with troubleshooting or recalling defective instruments. Particularly in safety-critical applications, it also meets the requirements for improved manufacturing documentation and reduces the risk of failure.

[0011] As long as manufacturing control devices and / or control of manufacturing process steps in progress are described within the scope of this invention, control and regulation devices or control and regulation interventions are also included thereunder.

[0012] According to the present invention, measurement values ​​obtained by means of a measurement value encoder and / or data obtained therefrom can be transmitted and used for monitoring or control of ongoing manufacturing process steps. The concept of data obtained from the measurement values ​​specifically includes, but is not limited to, data obtained through smoothing, compressing, summarizing, and / or mathematical processing of the measurement values ​​obtained by the measurement value encoder.

[0013] According to a preferred embodiment of the invention, the measured values ​​and / or data obtained by means of the measuring value encoder are transmitted in a hybrid manner, that is, at least partially wirelessly and partially via cable or wire connection. Advantageously, by transmitting the measured values ​​and / or data obtained therefrom in a hybrid manner, the rough boundary conditions of the manufacturing process and the material flow requirements during manufacturing are also met. The measured values ​​and / or data obtained therefrom can be transmitted wirelessly, for example, from a transmitter provided to the mold to a receiving unit that cooperates with the transmitter, which is fixedly mounted as part of a layer press or other suitable manufacturing equipment, either inside or outside the hot compression chamber. By loading the mold into the hot compression chamber, the cable laying for the measuring value encoder, which is common today, is eliminated. This reduces setup time and the risk of burns to machine operators when laying cables for the measuring value encoder is reduced. Meanwhile, the measured values ​​obtained inside the mold can be transmitted to the transmitter via cable or wire connection. This is because the temperature in the hot compression chamber and the pressure acting on the mold are equally robust and insensitive to errors. Furthermore, since the measurement encoder, as a lost sensor, cannot be reused, the use of a radio measurement encoder and the wireless transmission of the measurement value from the mold are very expensive. Conversely, if, for example, a thermocouple wire simultaneously constitutes both the measurement encoder and the signal line leading from the measurement encoder to the transmitter, the implementation is very low-cost.

[0014] According to an improved embodiment of the invention, a receiving unit that cooperates with the transmitter is disposed within the thermocompression chamber itself, and a cable or wire connecting the measured value or the data obtained therefrom is routed from the thermocompression chamber to the manufacturing control device disposed outside the thermocompression chamber. Advantageously, this ensures that the transmitter and receiving unit are spatially adjacent to each other. Thus, wireless data transmission can be performed with very low interference and low energy. For example, energy can be wirelessly supplied to the transmitter itself. Further data transmission from the receiving unit to the manufacturing control device is re-wired or wired and robustly constructed according to manufacturing boundary conditions.

[0015] According to an alternative embodiment of the invention, the receiving unit can be disposed outside the thermocompression chamber. Advantageously, the receiving unit is subjected to less intense thermal loading outside the thermocompression chamber, thus allowing for the use of particularly low-cost receiving units.

[0016] According to an improved embodiment of the invention, the transmitter is fluidly cooled within the thermal compression chamber. Cooling fluid is introduced or discharged via at least one fluid pipe. Air, preferably ambient air, can be used as the cooling fluid. Advantageously, the thermal load on the transmitter is reduced through fluid cooling. Therefore, damage to the transmitter is prevented.

[0017] According to an improvement of the invention, temperature, pressure, or humidity values ​​are determined as measurements. Advantageously, these measurements provide a basis for reporting on the quality or functionality of the circuit board. Simultaneously, these measurements can be used to intervene online in ongoing manufacturing process steps. In particular, the possibility of influencing ongoing manufacturing process steps online can be realized here to minimize the process or cycle time's impact on the quality or functionality of the circuit board without adverse effects. Here, maintaining and thus adjusting the pressure and / or temperature in the thermocompression chamber for such a long period ensures that the functional layers and insulating layers are reliably interconnected in the desired manner.

[0018] According to an improvement of the invention, in the ongoing manufacturing process steps, the target temperature and / or target pressure may be increased or adjusted differently, based on the measured values ​​and / or the data obtained therefrom, beyond predetermined values ​​for the target temperature or target pressure. In the ongoing manufacturing process steps, the hot compression chamber should be heated to the target temperature, and the mold should be loaded into the hot compression chamber at the target pressure. Similarly, it can be specified that the temperature-time and / or pressure-time curves to be followed in the ongoing manufacturing process steps are adapted or modified based on the measured values ​​and / or the data obtained therefrom. Attached Figure Description

[0019] Further advantages, features, and details of the invention will be revealed by the other dependent claims and the following description. Features mentioned therein may be important to the invention individually or in any combination. The accompanying drawings are for illustrative purposes only and are not intended to be limiting.

[0020] In the attached image:

[0021] Figure 1 A perspective partial view of an apparatus for manufacturing multilayer circuit boards according to the present invention is shown, the apparatus having an equipped multi-part mold, a mold logic module and a measurement value transmission module, wherein the lower mold of the mold is applied to a heating plate and the receiving unit of the measurement value transmission module is held on the heating plate;

[0022] Figure 2 Showing according to Figure 1 A magnified view of the details of the layout structure X;

[0023] Figure 3 Showing according to Figure 1 A side view of the layout structure;

[0024] Figure 4 Showing according to Figure 1 A top view of the layout structure;

[0025] Figure 5 Showing according to Figure 1 An exploded view of the layout structure shows that the equipped multi-piece mold, along with the mold logic module mounted thereon, is spaced apart from the heating plate; and

[0026] Figure 6 A schematic diagram of the device according to the present invention is shown, illustrating a portion of the layered hot press as a manufacturing control device. Detailed Implementation

[0027] The apparatus for manufacturing multilayer circuit boards according to the present invention includes a multi-part mold having a lower mold 2 and an upper mold 1, a measurement value encoder, and a mold logic module 7, wherein the measurement value detected by the measurement value encoder is introduced to the mold logic module via a signal line. The apparatus also includes a measurement value transmission module 12 having a receiving unit 9 and a transmission unit 10, and a data line 14 for continuing to transmit the measurement value or data obtained therefrom. The receiving unit 9 and the transmission unit 10 of the measurement value transmission module 12 are spatially separated from each other and are currently interconnected via a conduit 11.

[0028] A mold having an upper mold 1 and a lower mold 2, a mold logic module 7, a measurement value encoder, and a receiving unit 9 of a measurement value transmission module 12 are arranged together with multiple heating plates 3 in the hot compression chamber 20 of a layered hot press when the equipment according to the invention is used as specified. The transmission unit 10 of the measurement value transmission module 12 and the manufacturing control device 13 of the layered hot press, which is connected to the transmission unit 10 via a data line 14, are located outside the hot compression chamber 20. The manufacturing control device 13, the hot compression chamber 20, and the heating plates 3 are not part of the equipment according to the invention. However, they belong to the layered hot press together with the equipment according to the invention.

[0029] In manufacturing multilayer circuit boards, firstly, in a preparatory assembly step, the functional layer 5 and insulating layer 4 of the circuit board to be manufactured are alternately arranged in the mold outside the hot compression chamber 20 of a layered hot press, and layers are formed between the upper mold 1 and the lower mold 2. During layering, in the current embodiment of the invention, a total of six thermocouple wires 6 are arranged between the layers 4 and 5, which simultaneously constitute the measurement encoder and signal lines of the device according to the invention. The arrangement of the thermocouple wires 6 is preferably such that the thermocouple wires 6 are positioned outside the circuit board to be manufactured after the layer structure is cut.

[0030] Thermocouple wire 6 emerges from the layered structure and is guided to mold logic module 7, where contacts are made open. Mold logic module 7 is fixed to the lower mold 2 of the mold, and includes a housing 8, a transmitter, and other functional components for receiving and / or storing and / or reprocessing measured values. The internal structure of mold logic module 7 is configured such that measured values ​​introduced via signal lines reach the transmitter.

[0031] In the preparation for manufacturing multilayer circuit boards, multiple molds are pre-configured or pre-assembled in the manner described above and transported, preferably automatically, to a layered hot press via a suitable operating mechanism during the assembly process. The multiple molds are then loaded into the hot compression chamber 20 of the layered hot press such that each mold, with its lower mold 2 below it, rests on and is positioned relative to a heating plate 3. Preferably, the number of heating plates 3 in the hot compression chamber 20 is selected such that one heating plate 3 is provided under each lower mold 2, and additionally, another heating plate 3 is positioned above the upper mold 1 of the uppermost mold in the hot compression chamber 20.

[0032] When the mold is loaded into the hot compression chamber 20 of the layered hot press, the mold logic module 7, along with its transmitter, is positioned adjacent to the receiving unit 9 of the measurement value transmission module 12, which is also installed in the hot compression chamber 20. The spacing between the transmitter of the mold logic module 7 and the receiving unit 9 of the measurement value transmission module 12 is chosen such that it is possible to wirelessly transmit the measured value, or the data obtained therefrom, from the transmitter of the mold logic module 7 to the receiving unit 9.

[0033] The wireless transmission is currently exemplarily performed using a near-field communication (NFC) routine. The transmitter of the mold logic module 7 then includes, for example, an NFC coil (NFC: Near Field Communication), and the receiving unit 9 of the measurement value transmission module 12 is configured as an NFC reader or equipped with such an NFC reader. Here, the NFC coil and NFC reader cooperate to wirelessly transmit or transmit the measurement value or the data obtained therefrom. For example, power supply for the mold logic module 7 is provided via the measurement value transmission module 12 within the range of NFC communication.

[0034] To ensure the positioning of the transmitter of each mold relative to the receiving unit 9 of the measurement value transmission module 12 assigned to the corresponding mold during the process of positioning the mold on the heating plate 3, a support body 19 is provided on each heating plate 3, on which the receiving unit 9 is fixed. In the current embodiment of the invention, the support body 19 is exemplary constructed of a double L-shaped or Z-shaped profile.

[0035] To interconnect the functional and insulating layers 4 and 5 now positioned in the mold, the thermocompression chamber 20 is heated to approximately 180°C. Simultaneously, the heating plate 3 is moved, thus pressing the layers 4 and 5 together within the mold. After a holding time, which varies particularly with temperature, pressure, and the materials used for the functional and insulating layers 4 and 5, the layers 4 and 5 are then material-locked together, with adjacent functional layers 5 separated and insulated from each other by the insulating layers 4. Thermocouple wires 6 are fixedly connected to the layer structure. The thermocouple wires cannot be reused as lost sensors.

[0036] To protect the functional components of the mold logic module 7, and particularly the transmitter, from excessively high temperatures, fluid cooling for the mold logic module 7 is implemented in the current embodiment of the invention. The fluid cooling system includes two fluid lines 16 and 17 through which cooling fluid is introduced and discharged. Furthermore, an inlet opening 21 and an outlet opening 22 for the cooling fluid are provided on the housing 8 of the mold logic module 7.

[0037] A resilient connecting sleeve 18 connects the inlet and outlet openings 21, 22 to the fluid lines 16, 17. The connecting sleeve is fixed to the support body 19 on the side facing the mold logic module. The connecting sleeve 18 connects to the fluid lines 16, 17. Furthermore, the connecting sleeve 18 is positioned on the support body 19 such that it is placed over the inlet and outlet openings 21, 22 when the mold is loaded into the thermocompression chamber 20. Here, the connecting sleeve 18 can elastically deform. This deformation provides a clamping force, resulting in a fully sealed connection and only minimal leakage.

[0038] Cooling fluid reaches the inlet opening 21 of the housing 8 via the first fluid line 16 and the first connecting sleeve 18, and flows out via the outlet opening 22, the second connecting sleeve 18, and the second fluid line 17. The housing 8 itself currently serves as a fluid passage and connects the inlet and outlet openings 21 and 22. In this way, cooling is achieved for the functional components of the mold logic module 7 that are mounted in the housing 8.

[0039] For example, ambient air introduced from outside the thermal compression chamber can be used as a cooling fluid.

[0040] The manufacturing of multilayer circuit boards can be improved by using the device according to the invention as part of a layered hot press. Measurements determined by means of the thermocouple wires and / or the data obtained therefrom can be imported online, i.e., directly into the manufacturing control device 13 of the layered hot press during the ongoing manufacturing process steps. The manufacturing control device 13 can determine, with the aid of the measurements and / or the data obtained therefrom, whether intervention in the ongoing manufacturing process steps is necessary, and for example, to extend or shorten the holding time or to readjust the temperature or pressure. The manufacturing control device can, in particular, be configured to compare the measurements and / or the data obtained therefrom with stored and / or calculated predetermined values, particularly predetermined values ​​for the duration of the ongoing manufacturing process steps, for the target temperature, or for the target pressure, to heat the hot compression chamber 20 to the target temperature, and to load the mold in the hot compression chamber 20 at the target pressure. In this way, deviations between theoretical and actual process changes can be identified early and timely measures for fault avoidance or elimination can be introduced. Furthermore, the measurements and / or the data obtained therefrom can be stored for recording purposes.

[0041] The same components and their functions are indicated by the same reference numerals.

Claims

1. A method for manufacturing multilayer circuit boards, - Within the scope of the manufacturing method steps, the upper mold (1) and lower mold (2) of a multi-part mold, together with multiple functional layers (5) and at least one insulating layer (4) of the circuit board to be manufactured disposed therebetween, and at least one measuring value encoder, are pressed together and heated in a thermal compression chamber (20), and the measuring value encoder is used to detect the measuring value. The measured values ​​and / or the data obtained therefrom are transmitted to the manufacturing control device (13) during the ongoing manufacturing process steps, and the manufacturing control device (13) processes the measured values ​​and / or the data obtained therefrom with reference to predetermined values ​​of the measurement parameters for the measured value encoder, for monitoring the ongoing manufacturing process steps and / or for controlling the ongoing manufacturing process steps. Its features are, - Prior to the manufacturing method step, within the scope of the assembly method step, the plurality of functional layers (5) and the at least one insulating layer (4) are first layered and disposed between the lower mold (2) and the upper mold (1), and the at least one measuring value encoder is positioned between the upper mold (1) and the lower mold (2), such that the measuring value encoder is abutted against at least one functional layer (5) and / or insulating layer (4), and - Prior to the manufacturing method step and within the scope of the equipment method step, a plurality of pre-assembled molds together with the plurality of functional layers (5) and the at least one insulating layer (4) and the measuring value encoder are transported via a suitable operating mechanism to a layered hot press and loaded into the hot compression chamber (20) of the layered hot press, such that each mold is placed on the heating plate (3) from above with the lower side of its lower mold (2) and positioned relative to the heating plate.

2. The method of claim 1, wherein, The measured values ​​are transmitted wirelessly, at least in part, to the manufacturing control device (13).

3. The method according to claim 2, characterized in that, The measurements are transmitted in a hybrid manner, that is, at least partially wirelessly and partially via cable or wire connection.

4. The method according to claim 1, characterized in that, The measured value is derived from the mold via a cable or wire connection.

5. The method according to claim 1, characterized in that, The measured value is transferred from the hot compression chamber (20) to the manufacturing control device (13) located outside the hot compression chamber (20) via a cable or wire connection.

6. The method according to any one of claims 2 to 5, characterized in that, The measured value is wirelessly transmitted from a transmitter located in the thermocompression chamber (20) to a receiving unit (9) that works in conjunction with the transmitter.

7. The method according to claim 6, characterized in that, The transmitter is fluidly cooled in the thermal compression chamber (20) by introducing and / or exporting cooling fluid via at least one fluid line.

8. The method according to claim 6, characterized in that, When the mold is inserted into the thermocompression chamber (20), the transmitter is positioned and / or oriented relative to the receiving unit (9) together with the mold or as part of the mold.

9. The method according to any one of claims 1 to 5, characterized in that, Temperature and / or pressure and / or humidity values ​​are determined as measured values.

10. The method according to any one of claims 1 to 5, characterized in that, When the measured values ​​and / or the data obtained therefrom are processed by the manufacturing control device (13), the measured values ​​and / or the data obtained therefrom are compared with the stored reference values.

11. The method according to claim 10, characterized in that, The comparison is based on the predetermined value of the measurement parameter used for the measurement value encoder as a reference value.

12. The method according to any one of claims 1 to 5, characterized in that, The duration of the ongoing manufacturing method step is determined based on the measured value and / or the data obtained therefrom, and / or the ongoing manufacturing method step is continued until it exceeds a predetermined value for the duration of the ongoing manufacturing method step or ends before reaching the predetermined value for the duration of the ongoing manufacturing method step.

13. The method according to any one of claims 1 to 5, characterized in that, In the ongoing manufacturing process steps, the target temperature is increased beyond a predetermined value for the target temperature based on the measured value and / or the data obtained therefrom, thereby heating the thermal compression chamber (20) to the target temperature.

14. The method according to any one of claims 1 to 5, characterized in that, In the ongoing manufacturing process steps, the target temperature is adjusted according to the measured value and / or the data obtained therefrom, which is different from the predetermined value used for the target temperature, and the hot compression chamber (20) is heated to the target temperature.

15. The method according to any one of claims 1 to 5, characterized in that, In the ongoing manufacturing process steps, the target pressure is increased beyond a predetermined value for the target pressure based on the measured value and / or the data obtained therefrom, and the mold is loaded with the target pressure in the thermal compression chamber (20).

16. The method according to any one of claims 1 to 5, characterized in that, In the ongoing manufacturing process steps, the target pressure is adjusted according to the measured value and / or the data obtained therefrom, which differs from the predetermined value used for the target pressure, and the mold is loaded in the hot compression chamber (20) with the target pressure.

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