TW201325862A - An apparatus and a method for controlling temperature of a heating element in a thermocompression bonding process - Google Patents

Abstract

An apparatus and a method for controlling temperature of a heating element of a thermocompression bonding machine in a thermocompression bonding process is disclosed. An input temperature profile is applied to apply heat to the heating element in the thermocompression bonding machine. A controller of the thermocompression bonding machine can be configured to receive a heating element temperature signal corresponding to a temperature of the heating element. A temperature compensation profile can be generated in the controller based on the heating element temperature signal and a input temperature signal corresponding to the input temperature profile. Power input to the heating element can be controlled in the controller based on the temperature compensation profile.

Description

Temperature control device and method for heating element in thermocompression bonding process

The present invention relates to the field of thermocompression bonding of intermediate film layers to join different materials. More particularly, the present invention relates to an apparatus and method for controlling the temperature of a heating element in a thermocompression bonding process for bonding substrates.

Thermocompression bonding machines and processes are often used to manufacture consumer electronic devices including: mobile phones, notebook computers, touch panels, electronic components, display modules, touch panels, liquid crystal display (LCD) panels, And similar.

Conventional thermocompression bonding machines have heating elements (often referred to as hot electrodes) for applying heat and pressure to cure the bonding layer between the two substrates to bond the substrates to form a substrate assembly. The substrate may comprise a polarizer film material, a film material, a printed circuit board material, a glass material, or any material suitable for meeting the requirements in a thermocompression bonding process. The bonding layer material used in the thermocompression bonding may include a solder material, an anisotropic conductive film (ACF), or any viscous film layer suitable for interconnection of substrates.

In order to achieve and achieve optimal bonding between the substrates, it is generally recommended that the temperature profile for curing the bonding layer (often referred to as "bonding wire temperature profile") is based on the target bonding wire temperature profile specified by the bonding material supplier. However, this situation is often difficult to achieve in practice due to heat loss in the thermocompression bonding process. Such heat loss can be attributed, for example, to the thermal resistance of the bonding layer or/and substrate to be bonded and the heat loss in the parts of the thermocompression bonding machine. Due to the bonding process The heat loss, the bonding layer may not be cured according to the specified bond wire temperature profile, and this situation may result in defects such as voids or insufficient adhesion strength of the bond.

Currently, before manufacturing a new product such as a flex-on-glass substrate assembly using a bonding layer material having a bonding wire temperature profile, it is necessary to determine the heating of the hot electrode in the thermocompression bonding machine. Enter the temperature curve.

In order to determine the input temperature profile, the user must often measure the actual temperature ("bonding wire temperature") in the bond wires of the substrate assembly to be bonded.

To compensate for the heat loss explained above, the operator must adjust the input temperature profile to be applied to the hot electrode. However, it is difficult to determine the amount by which the input temperature profile should be adjusted, since the amount of adjustment depends on the experience of the operator. Figure 1 illustrates a method 21 for an operator to determine an input temperature profile. Referring to Figure 1, in a first test joint for determining the temperature of the hot electrode, the thermocouple is fixed 22 in the bond wire and by a specified bond wire temperature profile based on the bond layer to be used to produce the substrate assembly (" The input temperature profile of the target temperature curve ") is used to heat the 23 hot electrode. Typically, in the first trial joint, the bond line temperature profile measured in the bond line is below the specified bond line temperature profile due to the heat loss explained above. Thus, in step 25, if the measured bond line temperature profile is not equal to the target temperature profile, the user must adjust the input temperature profile in step 26 and apply the adjusted input temperature profile at step 23. To achieve the target bond line temperature profile, a temperature measurement is taken at the bond line and the input temperature profile is adjusted until a target temperature profile is reached at the bond line.

Depending on the experience of the operator, a typical operator must often perform a series of test joints before the hot electrode temperature profile for production can be determined in step 27.

However, the shortcomings of the method 21 described above are heavily dependent on user attention and user decision making. User decisions can be influenced by factors such as user training, experience, and product knowledge. In addition, the high user dependency levels associated with such methods typically add significant time cost. In a mass production manufacturing environment, time cost significantly affects product yield.

According to a first aspect of the present invention, there is provided a method of controlling the temperature of a heating element in a thermocompression bonding machine to compensate for heat loss during a thermocompression bonding process, the thermocompression bonding process comprising an input temperature profile Applied to the heating element to apply heat to a substrate assembly to be joined, the method comprising: a) receiving a heating element temperature signal corresponding to a temperature of one of the heating elements in a controller; b) based on the heating a component temperature signal and an input temperature signal corresponding to the input temperature profile to generate a temperature compensation curve in the controller; and c) controlling a power input to the heating element based on the temperature compensation curve; wherein the input temperature The curve is based on a target temperature profile of a bond line in the substrate assembly.

The step of generating the temperature compensation curve may include: Applying a first series of bond line temperature differential values for a series of times in the controller; a series of heating element temperature values from temperature data corresponding to the heating element and corresponding to the input temperature profile at a series of times A series of input temperature values are used to calculate a series of heating element temperature differential values; a series of temperature compensation values are derived based on the series of heating element temperature differential values and the first series of bonding wire temperature differential values at a series of times.

The step of controlling the power input can include comparing the temperature compensation curve with a predetermined series of power settings for applying heat to the heating element; generating a temperature based on a power setting from the predetermined series of power settings The compensated power signal.

According to a second aspect of the present invention, there is provided a program encoded in a computer readable recording medium, the program causing a computer to execute the method.

According to a third aspect of the present invention, there is provided a computer readable recording medium recording a program in a computer readable form, the program causing a computer to execute the method.

The step of applying the first series of bond wire temperature differential values may include: a) measuring a series of bond wires at a series of times corresponding to one of the bond wires of one of the substrate assemblies in the thermocompression bonding machine a temperature value; b) calculating a series of bond wire temperature differential values from the series of bond wire temperature values at the series of times and the series of input temperature values to generate a bond wire temperature differential curve in one of the thermocompression bonding machines ; c) storing the bond wire temperature differential curve in a memory device.

The memory device can be a memory of the controller.

The method can further include: receiving, in the controller, a bond wire temperature signal corresponding to a bond wire temperature of the bond wire; comparing the bond wire temperature signal to the input temperature signal in the controller; at the controller The first series of bond wire temperature differential values are compensated based on a comparison of the bond wire temperature signal to the input temperature signal; and the second series of compensated bond wire temperature differential values are derived in the controller.

The step of compensating for the first series of bond wire temperature differential values can include applying a multiplier gain to the first series of bond wire temperature differential values.

According to a fourth aspect of the present invention, there is provided a thermocompression bonding machine for compensating for heat loss in a thermocompression bonding process, the thermocompression bonding process comprising applying an input temperature profile to a heating element to apply heat To a substrate assembly to be joined, the bonding machine includes: a first input interface for receiving a heating element temperature profile of the heating element; and a second input interface for receiving the substrate combination to be bonded a bonding wire temperature profile of the body; a controller configured to: a) receive a heating element temperature signal corresponding to the heating element temperature profile of the heating element; b) based on the heating element temperature signal and a corresponding Generating a temperature compensation curve for the input temperature signal of the input temperature profile; and c) controlling the power input to the heating element based on the temperature compensation curve.

The memory can be a memory of the controller.

The bonding machine can further include an input interface adapted to enable the controller to record the temperature differential profile on a recording medium.

The bonding machine can further include a first amplifier coupled to a first analog-to-digital converter, the first analog-to-digital converter configured to convert one of the heating element temperature profile and a bonding line temperature profile into a digital signal; And a second amplifier coupled to a second analog-to-digital converter, the second analog-to-digital converter for converting one of the heating element temperature profile and a bond line temperature profile into a digital signal.

According to a fifth aspect of the present invention, there is provided a device for controlling the temperature of a heating element in a thermocompression bonding machine to compensate for heat loss in a thermocompression bonding process, the thermocompression bonding process comprising an input The temperature profile is applied to a hot electrode to apply heat to a substrate assembly having a bond line, the device having: a processor; and a memory; the device is configured to target a series of Exchanging instructions stored in the memory: a) receiving a heating element temperature signal corresponding to a temperature of one of the heating elements in a controller; b) based on the heating element temperature signal and a corresponding to the input temperature profile Input temperature signal to generate a temperature compensation curve in the controller; and c) controlling the power input to the heating element based on the temperature compensation curve.

The apparatus can be configured to store a series of input temperature values corresponding to the temperature of the heating element at the series of times.

The apparatus can be configured to: a) receive a first series of bond line temperature differential values for a series of times in the controller; b) a series of heating element temperature values from a temperature profile corresponding to the heating element and a Calculating a series of heating element temperature differential values at a series of input temperature values corresponding to the input temperature profile; c) based on the series of heating element temperature differential values and the first series of bonding wire temperature differences at a series of times The value is used to derive a series of temperature compensation values.

The apparatus can be configured to: a) receive a bond wire temperature signal corresponding to a bond wire temperature of the bond wire; b) compare the bond wire temperature signal to the input temperature signal; c) based on the bond wire temperature signal Compensating for the first series of bond line temperature differential values as compared to the input temperature signal; and d) deriving the second series of compensated bond line temperature differential values.

The apparatus can be configured to apply a multiplier gain to the first series of bond wire temperature differential values to obtain the second series of compensated bond wire temperature differential values.

The device can be configured to: Comparing the temperature compensation curve with a predetermined series of power settings for applying heat to the heating element; and generating a temperature compensated power signal based on a power setting from the predetermined series of power settings.

An advantage of generating the temperature compensation curve in the controller is that the temperature control can be synchronized in the thermocompression bonding machine during a thermocompression bonding process.

One advantage of controlling the power input based on the temperature compensation curve is that a method for compensating for heat loss can be automated and there is less reliance on the operator's knowledge of how to adjust the input temperature to be applied to the heating element. .

Another advantage of controlling the power input is that the temperature of the heating element can be controlled and compensated based on the temperature compensated power signal.

Various specific examples of the invention will now be described by way of example only and with reference to the accompanying drawings.

2 is an isometric view of a thermocompression bonding machine 30 that can be used in a thermocompression bonding process for fabricating, for example, a touch panel display, a glass-on-flex circuit assembly, or a different substrate material. The project of the assembly. 2, the thermocompression bonding machine 30 has a hot electrode assembly 31 (generally referred to as a hot electrode) for applying heat to bond the substrate assembly before assembling the heating element 33. The thermocompression bonding machine 30 has a platform 14 for supporting the substrate assembly during the bonding process. Bonding machine 30 also includes an input unit 32 for receiving an input temperature profile. The input unit 32 can be, for example, a touch type A panel display, or may include an indicator device for receiving input from an operator. The thermocompression bonding machine 30 can have a first input interface for receiving a first temperature input corresponding to the bond wire temperature measurement and a second input interface for receiving a second temperature input corresponding to the hot electrode temperature measurement. Based on the hot electrode temperature measurement, the thermocompression bonding machine has a controller 35 that can perform temperature compensation and control the power input to the heating element 33 based on temperature compensation to achieve target engagement in the bond wires of the substrate assembly Line temperature. Details of the heating element 33 and the controller 35 will be described in FIGS. 3 and 4.

The first input interface and the second input interface of the thermocompression bonding machine 30 can be or include a socket plug, a temperature reader connector, or the like, configured to enable the controller 35 to receive via the temperature measuring device ( The temperature value measured, for example, by a thermocouple connected to a temperature measuring instrument. In one embodiment, the thermocompression bonding machine can also be configured to include a third input interface that can detect and receive from, for example, flash memory devices, hard disk drives, optical drives, and the like. The program for storing media. Further, the controller 35 can read the program via a data cable that can be connected to an external computer where the execution program is located. The first input interface and the second input interface can be connectors suitable for receiving a thermocouple input or the like.

3 is a schematic block diagram of an assembly of the thermocompression bonding machine 30 with respect to temperature control of the heating element 33. Controller 35 is configured to receive input temperature profile 45 from a user or operator via input device 32. The controller 35 communicates with the ignition unit 34, such as an ignition mechanism, by transmitting a signal 41 to control The operating state of the heating element 33 and/or the temperature of the heating element 33 are controlled. It will be appreciated that a series of drive assemblies, such as servo motors, are operatively coupled between the controller 35 and the heating element 33 to facilitate movement or positioning of the heating element 33.

Additionally, the thermo-bonding machine 30 can include a first amplifier 49 (AMP 49) coupled to a first analog-to-digital converter 50 (ADC 50) and a second amplifier coupled to a second analog-to-digital converter 52 (ADC 52). 51 (AMP 51). The AMP 49 amplifies the first temperature input 43 received via the first input interface, and the ADC 50 can convert the amplified temperature input 43 into a digital signal 53 that is communicated to the controller 35 via the input 40. For example, if the first temperature input 43 is a series of bond line temperature measurements at a series of times, each of the temperature values can be converted to a signal 53 that can be considered a bond line temperature profile. Similarly, the second temperature input 44 can be a series of temperature measurements measured on the heating element 33 at a series of times. The AMP 51 can amplify the second temperature input 44 to obtain an amplified temperature input 44 that is passed to the second analog to digital converter 52 (ADC 52). The second ADC 52 converts the amplified temperature input 44 into a digital signal 54 that can be passed to the controller 35 via the input 39. Digital signal 54 can be considered a heating element temperature profile. Controller 35 can be configured to process digital signals 53 and 54 to control or adjust power input signal 41 to firing unit 34. Based on the power input signal 41 from the controller 35, the firing unit 34 applies an ignition signal 42 to heat the hot electrode 33 to achieve the desired temperature in the bond wire.

Referring to FIG. 4, controller 35 can include a processor 55 configured to process signals corresponding to bond wire temperature profiles and heating element temperature profiles. The processor 55 can be configured to: for a series of moments, store a series of input temperature values corresponding to the temperature of the heating element at the series of times; store corresponding to the temperature sensed at the bonding line at the series of times The temperature values sensed by the respective series; a series of temperature difference values are calculated from the series of input temperature values and the sensed temperature values of the series; and the compensated temperature profile is derived from the series of temperature differential values.

The controller 35 can have a memory 58 for storing programs executable by the controller 35. The processor 55 can also store the signal 56 in the memory 58 or retrieve the signal 57 from the memory 58 corresponding to the stored data. Alternatively, controller 35 may have a reader interface circuit (not shown in FIG. 4) adapted for reading from a recording medium such as a flash memory card. As an example, controller 35 can be a printed circuit board (PCB) assembly. Although a signal 41 is sent from processor 55 to perform the function in FIG. 4, it will be appreciated that processor 55 can transmit a number of signals depending on the desired function to be performed by the controller.

FIG. 5 is a schematic block diagram of a thermocompression bonding machine arrangement 60 based on the hot press 30 of FIG. The provision 60 is used to determine the bond line temperature differential curve of the substrate assembly 66 to be bonded prior to initiating the substrate assembly in the thermocompression bonding process. The substrate assembly 66 may be composed of an intermediate bonding layer, a flexible circuit substrate 67, and a glass substrate 68. Alternatively, the substrate assembly 66 may be a flexible circuit base The board 67 and the printed circuit board substrate 68 are composed. In setting 60, the intermediate bonding layer is not included. An input temperature profile based on a specified bond line temperature profile ("target temperature profile") of the bond layer can be applied to the heating element 33. The input temperature profile 61 is provided by the operator and can be programmed or stored in the memory of the controller 35.

The thermocouple 64 is fixed in the bonding wire 65 of the substrate assembly 66 to measure a series of bonding wire temperature values in the bonding wire 65 at a series of times to obtain the measured bonding wire temperature profile. The measured bond wire temperature profile is amplified and converted by the ADC into a digital signal for receipt by controller 35 via input interface 39. The controller 35 calculates a series of temperature difference values from the input temperature curve 61 and the bonding wire temperature curve according to the equation (Equation 1): D(x)=T _TBL -T _MBL , --- (Equation 1)

Where D(x) is a temperature difference curve corresponding to a series of temperature difference values at a series of times, T _TBL is a series of target wire temperature values at a series of times, and T _MBL is a series of time series The bond wire temperature value is measured. The series of target bond line temperature values may form a target bond line temperature profile, and the input temperature profile 61 may be based on the target bond wire temperature. The following table (Table 1) illustrates an embodiment in which one series of temperature differential values are obtained from setting 60.

The following graph (graph 1) is an example of a temperature vs. time curve based on the values in Table 1, plotting the measured bond wire temperature and target bond wire temperature at a series of times.

The temperature differential curve D(x) can be stored in a memory or memory device in the controller 35. It should be understood that D(x) depends on the bonding layer and the substrate on which the substrate assembly is formed. Therefore, the equation for D(x) (Equation 1) can be similarly applied to different substrate materials and different bonding layer materials.

By calculating the temperature difference curve based on the substrate assembly to be bonded, it is recognized The procedure of Figure 7 enables the thermocompression bonding machine 30 to quickly perform automated bond line compensation based on different substrate assembly configurations and materials. An advantage of measuring the temperature of the bond wire temperature in a thermocompression bonding machine is that the temperature measurement procedure can be synchronized with the thermocompression bonding machine. The advantage of synchronization is that the operator can determine the temperature differential curve D(x) in a single setting without the need for an external temperature measuring instrument. Additionally, the bond line temperature differential curve can be stored in the memory of the memory device or controller 35. In one scenario, the operator can set the number of times required to perform a thermocompression bonding setup procedure to determine the bond line temperature differential curve for the substrate assembly. For example, the input unit of the thermocompression bonding machine can be configured to allow an operator to enter the number of times the thermocompression bonding setup procedure is performed.

FIG. 6 is a schematic block diagram of a thermocompression bonding machine arrangement 80 for bonding a substrate assembly 70 in a thermocompression bonding process. The substrate assembly 70 is composed of an intermediate bonding layer 71, a flexible circuit substrate 72, and a glass substrate 73. In the thermocompression bonding process of the substrate assembly 70, a thermocouple 84 is mounted to the heating element or the hot electrode 33 to measure a series of heating element temperature values at a series of times which constitute the measured heating element temperature profile. The thermocouple 84 can be located at the center of the heating element 33 such that the temperature of the heating element can be uniform. Controller 35 can be configured to receive a series of heating element temperature values for a series of time-measured heating elements via second input interface 40. In the controller 35, a temperature compensation curve can be generated based on the heating element temperature profile according to the equation (Equation 2).

A=T _TBL -T _MT +D(x)---(Equation 2)

For a series of moments, A is a series of temperature compensation values at the time of the series, T _TBL is a series of target bonding wire temperature values at the time of the series, and T _MT is a series of quantities at the time of the series. Measure the heating element temperature value. The T _TBL can be typed into the controller by the user as an input temperature profile. The following table (Table 2) illustrates an embodiment that relies on setting 80 and obtains a series of temperature compensation values based on Equation 2.

Based on the temperature compensation curve generated based on Equation 2, controller 35 can then be configured to control the power input to the heating element to compensate for the temperature profile of the bond wire. In one embodiment, each condition of A is associated with a power input that relates to a power setting and a duration setting associated with the firing unit. The duration setting can be measured in milliseconds, and the power setting can be measured in volts or watts. Specifically, Table 3 illustrates A look-up table consisting of a series of temperature compensation curve conditions corresponding to the power input to the heating element and the duration (time) of the power applied to the heating element. Temperature compensation curve conditions can be derived and stored in the controller.

By comparing the value of the temperature compensation curve A with one of the series of power inputs listed in Table 3, the controller 35 can control the power input to the heating element to increase or ramp the temperature of the heating element based on power and duration. (ramp). Higher power and longer duration will mean that the ramp of the temperature of the heating element will be higher. It should be understood that the quality of the joint may also depend on the coefficient of thermal expansion of the material. In one scenario, after applying Equation 2 to derive the temperature compensation value and applying the power input based on the temperature compensation value, the measured bonding wire temperature may be equal to the target bonding wire temperature, that is, the following conditions.

T _MBL =T _TBL ---(Condition 1)

However, for heat transfer in transient systems where boundary conditions can vary, such as in a thermocompression bonding process, the heat loss in the thermocompression bonding process is non-linear. For example, when the heating element is at a higher temperature, there is more heat loss such that the heat loss causes the measured bond wire temperature to be below the target bond wire temperature, as described in the following conditions: T _MBL <T _TBL ---(Condition 2)

In the case where the above condition 2 exists, a function can be implemented to compensate for the loss at a higher temperature. In a specific example, D(x) may be modified to obtain compensated D'(x) by applying multiplier gain G to D(x) [ie, in this case, D'(x) =G ^* D(x)], thereby compensating for heat loss according to the equation (Equation 3), A'=T _TBL -T _MT +G ^* D(x)---(Equation 3), where A' is Temperature compensation curve, and G is the multiplier gain.

G can be obtained based on the reversal (i.e., the test bonding test on the thermocompression bonding machine). In order to optimize the bonding wire temperature in the thermocompression bonding process, the preferred conditions are as follows: G = 1.2 - (- condition 3)

Still further, in a specific example, D(x) may be modified to obtain compensated D'(x) by adjusting T _TBL and repeating the procedure for determining the bond line temperature differential curve based on setting 60 in FIG.

7 is a flow diagram of a method 90 performed by controller 35 of FIG. 4C for determining a temperature differential curve to compensate for heat loss. Will refer to the thermal crimping of Figure 5 The setup is used to describe the flow for determining the temperature differential curve. When the target temperature profile is applied to the heating element 33 in step 91, the temperature of the bonding wire temperature can be measured in step 92 and recorded in the memory of the controller 35. In step 93, the temperature difference curve can be calculated by controller 35 based on the target temperature profile and the measured bond line temperature profile. In step 94, the temperature differential curve can be stored in the memory device. The memory device can be a memory in the controller 35, or a recordable medium such as a flash memory card.

FIG. 8 is a flow diagram of a method 100 for compensating for heat loss during a thermocompression bonding process. In step 101, a target temperature profile is applied to the heating element 33. In step 102, the temperature of the heating element 33 can be measured and recorded in the memory of the controller 35. In step 103, temperature compensation curve A can be calculated using Equation 2 described above, and controller 35 can use temperature compensation curve A to control the power input to heating element 33 to compensate for heat loss in step 104. In one scenario, the bond wire temperature of the substrate assembly can be measured to determine if the bond wire temperature is equal to the target bond wire temperature required to achieve optimum bond quality in the substrate assembly.

9 is a flow chart of another method 200 for compensating for heat loss during a thermocompression bonding process. Steps 201, 202, 203 in method 200 of FIG. 9 are similar in operation to steps 101, 102, and 103 in method 100 of FIG. In step 204, the controller controls the power input to the heating element 33 based on the temperature compensation value in step 203, and measures the bonding wire temperature in step 205. In step 206, the measured bond wire temperature is checked to see if condition 1 is satisfied, that is, whether T _MBL = T _TBL is satisfied. If condition 1 (corresponding to no condition) is not satisfied, that is, T _MBL <T _TBL , then the compensated bond line temperature differential curve D'(x) is calculated in step 208, and steps 201 and 202 are repeated to be in steps A second compensation value A' is obtained in 203. Calculating the temperature compensation value A' according to the equation in step 208: A'=T _TBL -T _MT +D(x), where D(x)=D'(x), the D'(x) corresponding to the map The compensated bond line temperature differential curve obtained by method 90 of 7. In the first production operation time, the G value is set to 1. However, depending on the measured bonding wire temperature, the G value can be adjusted to 1.2. Based on the temperature compensation value A', the power input to the heating element can be controlled, and when the condition T _MBL = T _TBL is satisfied (ie, corresponding to the condition in 209), the routine ends.

FIG. 10A is a flow chart showing another method 210 of determining a compensated bond line temperature differential curve D'(x). In step 211, a second input temperature profile T'(x) is applied to the heating element. T'(x) is calculated according to the following equation: T'(x) = T _TBL + D(x), where D(x) corresponds to the temperature difference curve obtained according to the method 90 in FIG. Similar to step 92 of method 90, in step 212, the bond wire temperature _T'MBL is measured and recorded in the memory of controller 35. In step 213, controller 35 may calculate compensated temperature differential curve D'(x) based on the second input temperature profile and the measured bond line temperature profile. In one scenario, method 210 can be used in applications where the substrate assembly to be bonded is comprised of a flexible circuit substrate and a printed circuit board having a conductive metal circuit pattern such as a copper circuit pattern.

FIG. 10B is a flow chart showing another method 215 of determining a compensated bond line temperature differential curve D'(x). Similar to step 91 of method 90 in Figure 7, the target temperature profile T _TBL can be applied to the hot electrode. Similar to step 92 of method 90, in step 217, the bond wire temperature T _MBL is measured and recorded in the memory of controller 35. In step 218, the controller 35 may calculate the compensated temperature differential curve D'(x) according to the following equation: D'(x)=G ^* (T _TBL -T _MBL ), where G is based on the hot press The derived multiplier gain. In the first production operation time, the G value is set to 1. However, depending on the measured bonding wire temperature, the G value can be adjusted to 1.2. Based on the temperature compensation value A', the power input to the heating element can be controlled, and when the condition T _MBL = T _TBL is satisfied (ie, corresponding to the condition in 209), the routine ends. In one scenario, method 215 can be used in applications where the substrate assembly to be bonded is comprised of a flexible circuit substrate and a glass substrate.

11 is a flow chart showing a routine 400 for controlling power input to a heating element based on the temperature compensation value A or A' in step 104 of FIGS. 8 and 9. When control of the power input to the heating element 33 is initiated in step 401, the temperature compensation value A or A' is compared in step 402 with a series of predetermined power input settings corresponding to a series of conditions of A or A'. For example, power input settings can include power settings (measured in volts) and ignition orders The duration of the ignition circuit in element 34 is set and the condition of A or A' can be associated with a predetermined power setting. For example, referring to Table 3, if the value of A or A' is less than 0.1, the power is set to 1 and the duration is set to 1, so a set of predetermined power input settings are selected based on the condition of A in step 403. The duration setting can be a time setting measured in milliseconds. Thus, in step 404, power is applied to the hot electrode 33 based on the selected power input setting to apply heat to the substrate assembly.

An advantage of the above temperature compensation method is that a one-time setting can be performed for the thermocompression bonding of each type of product based on the same substrate assembly. It will be appreciated that in order to heat the heating element to the desired temperature to compensate for heat loss in the bond wire, the ignition unit or ignition circuit can be configured accordingly. For example, the number of points in the temperature profile can vary, such as the temperature approaching the set temperature, and the duration of the ignition will be small. When the duration is small, the ignition frequency may be large. Thus, the number of points changes throughout the temperature profile. It should be understood that the above method can be used in standard ignition units known to those skilled in the art of thermocompression bonding. For example, the firing unit can include a high current or high voltage device operatively coupled to an ignition relay circuit for controlling the high current device by the controller. The ignition relay circuit can include a device for switching a high current device, such as a power relay switch, a semiconductor switch, or the like. The high current device can be a heater or transformer (having a different rating) that can be used to achieve a different wattage (power level) of the bond wire temperature to the target bond wire temperature based on the temperature compensation curve. Can make every new quickly The temperature compensation cycle of the substrate assembly is optimized.

An advantage of the above method according to a specific example is that the temperature compensation of the bonding process is less dependent on the skill of the operator, since the operator does not need to adjust the input temperature in order to compensate for the bonding line in the substrate assembly in the thermocompression bonding process. Heat loss.

Although the specific examples of the present invention have been particularly shown and described with reference to the specific embodiments, it is understood by those skilled in the art Various changes in form and detail are made therein. The scope of the invention is therefore indicated by the scope of the appended claims.

14‧‧‧ platform

21‧‧‧Method for the operator to determine the input temperature curve

30‧‧‧Hot press bonding machine

31‧‧‧Thermal electrode assembly

32‧‧‧Input unit/input device

33‧‧‧ heating elements

34‧‧‧Ignition unit

35‧‧‧ Controller

39‧‧‧ input

40‧‧‧Input/second input interface

41‧‧‧Signal/power input signal

42‧‧‧Ignition signal

43‧‧‧First temperature input / amplified temperature input

44‧‧‧Second temperature input/amplified temperature input

45‧‧‧Input temperature curve

49‧‧‧First Amplifier/AMP

50‧‧‧First analog-to-digital converter/ADC

51‧‧‧Second amplifier/AMP

52‧‧‧Second analog-to-digital converter/ADC

53‧‧‧ digital signal

54‧‧‧ digital signal

55‧‧‧Processor

56‧‧‧ signal

57‧‧‧ signal

58‧‧‧ memory

60‧‧‧ thermocompression bonding machine settings

61‧‧‧ Input temperature curve

64‧‧‧ thermocouple

65‧‧‧bonding line

66‧‧‧Substrate assembly

67‧‧‧Flexible circuit substrate

68‧‧‧ glass substrate

70‧‧‧Substrate assembly

71‧‧‧Intermediate bonding layer

72‧‧‧Flexible circuit substrate

73‧‧‧ glass substrate

80‧‧‧ thermocompression bonding machine settings

84‧‧‧ thermocouple

90‧‧‧Method for determining the temperature difference curve to compensate for heat loss

100‧‧‧Methods for compensating for heat loss in a thermocompression bonding process

200‧‧‧Another method for compensating for heat loss in a thermocompression bonding process

210‧‧‧Another method for determining the compensated bond line temperature differential curve D'(x)

215‧‧‧An alternative method for determining the compensated bond line temperature differential curve D'(x)

400‧‧‧Procedure for controlling the power input to the heating element

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a flow chart showing a known procedure for determining an input temperature profile of a heating element to be applied to a hot press; Fig. 2 is an isometric view of a thermocompression bonding machine according to a specific example; Figure 4 is a schematic block diagram of a controller in a thermocompression bonding machine; Figure 5 is a schematic block diagram of a thermocompression bonding machine; Figure 6 is a thermocompression bonding Schematic block diagram of the process of thermocompression bonding machine setup; Figure 7 is a flow chart of a method for determining a temperature differential curve; Figure 8 is a temperature control of the heating element during the thermocompression bonding process to compensate for heat FIG. 9 is a flow chart of a method for controlling the temperature of a heating element to compensate for heat loss in a thermocompression bonding process; FIG. 10A is a method for determining a compensated bonding line temperature differential curve according to a specific example; Flowchart; FIG. 10B is a flow chart of a method of determining a compensated bond line temperature differential curve; and FIG. 11 is a flow chart of a method for controlling power input to a heating element based on a temperature compensation curve.

100‧‧‧Methods for compensating for heat loss in a thermocompression bonding process

Claims (21)

A method of controlling the temperature of a heating element in a thermocompression bonding machine to compensate for heat loss during a thermocompression bonding process, the thermocompression bonding process including applying an input temperature profile to the heating element to apply heat to the a substrate assembly to be bonded, the method comprising: a) receiving a heating element temperature signal corresponding to a temperature of one of the heating elements in a controller; b) based on the heating element temperature signal and a corresponding to the input temperature profile Inputting a temperature signal to generate a temperature compensation curve in the controller; and c) controlling a power input to the heating element based on the temperature compensation curve; wherein the input temperature profile is based on one of the substrate assemblies A target temperature profile of the bond wire. The method of claim 1, wherein the generating the temperature compensation curve comprises: applying, in the controller, a first series of bonding wire temperature differential values for a series of times; and a temperature data corresponding to the heating element The series of heating element temperature values and a series of input temperature values corresponding to the input temperature profile at a series of times to calculate a series of heating element temperature differential values; based on the series of heating element temperature differential values and the first of the series of times The series of wire temperature differential values are used to derive a series of temperature compensation values. The method of claim 1, wherein controlling the power input comprises: comparing the temperature compensation curve with a predetermined series of power settings for applying heat to the heating element; based on power settings from the predetermined series A power set value of the value produces a temperature compensated power signal. A program encoded in a computer readable recording medium, which causes a computer to execute the method of claim 1 of the patent scope. A computer readable recording medium for recording a program in a computer readable form, the program causing a computer to execute the method of claim 1 of the patent scope. The method of claim 2, wherein applying the first series of bonding wire temperature differential values comprises: a) measuring a series of times in the thermocompression bonding machine corresponding to one of the bonding wires of the substrate assembly a series of bond wire temperature values at one of the temperatures; b) calculating a series of bond wire temperature differential values from the series of bond wire temperature values at the series of times to control one of the controllers at the thermocompression bonding machine A bonding line temperature differential curve is generated; c) storing the bonding wire temperature differential curve in a memory device. The method of claim 1, wherein the memory device is a memory of the controller. The method of claim 1, wherein the method further comprises: receiving, in the controller, a temperature corresponding to one of the bonding wires Bonding a line temperature signal; comparing the bond wire temperature signal to the input temperature signal in the controller; compensating the first series of bond wire temperatures based on a comparison of the bond wire temperature signal and the input temperature signal in the controller a differential value; and deriving a second series of compensated bond line temperature differential values in the controller. The method of claim 1, wherein compensating the first series of bond wire temperature differential values comprises applying a multiplier gain to the first series of bond wire temperature differential values. A thermocompression bonding process for bonding a glass substrate to a flexible circuit substrate in accordance with the steps of the method of claim 1 of the patent application. A thermocompression bonding machine for compensating for heat loss in a thermocompression bonding process, the thermocompression bonding process comprising applying an input temperature profile to a heating element to apply heat to a substrate assembly to be bonded, the bonding The machine includes: a first input interface for receiving a heating element temperature profile of the heating element; a second input interface for receiving a bonding wire temperature profile of the substrate assembly to be bonded; a controller Having been configured to: a) receive a heating element temperature signal corresponding to the heating element temperature profile of the heating element; b) generate based on the heating element temperature signal and an input temperature signal corresponding to the input temperature profile a temperature compensation curve; and c) controlling the power input to the heating element based on the temperature compensation curve. The bonding machine of claim 11, further comprising: a first amplifier connected to a first analog-to-digital converter, the first analog-to-digital converter for using the heating element temperature profile and a bonding wire temperature curve Converting one of the signals into a digital signal; and a second amplifier coupled to a second analog-to-digital converter for converting one of the heating element temperature profile and a bonding wire temperature profile Into a digital signal. The bonding machine of claim 11, wherein the controller is configured to: calculate a series of temperature difference values based on the input temperature profile and the bonding wire temperature profile and the heating element temperature profile to Obtaining a temperature difference curve; calculating a temperature compensation curve based on the series of temperature difference values; and controlling a power input input to the heating element based on the temperature compensation curve. The bonding machine of claim 11, wherein the controller has a memory for storing one of: the input temperature profile, the heating element temperature profile, or the bonding wire temperature profile. The bonding machine of claim 13 further comprising an input interface adapted to enable the controller to vary the temperature difference The partial curve is recorded on a recording medium. A device for controlling the temperature of a heating element in a thermocompression bonding machine to compensate for heat loss during a thermocompression bonding process, the thermocompression bonding process comprising applying an input temperature profile to a hot electrode to apply heat To a substrate assembly having a bond wire, the device has: a processor; and a memory; the device is configured to execute instructions stored in the memory for a series of times under control of the processor: a) receiving a heating element temperature signal corresponding to a temperature of one of the heating elements in a controller; b) generating in the controller based on the heating element temperature signal and an input temperature signal corresponding to the input temperature profile a temperature compensation curve; and c) controlling a power input to the heating element based on the temperature compensation curve. The device of claim 16, wherein the device is configured to store a series of input temperature values corresponding to the temperature of the heating element at the series of times. The device of claim 16, wherein the device is configured to: a) receive a first series of wire temperature differential values for the series of times in the controller; b) from the corresponding heating element Temperature data for a range of heating element temperatures a series of input element temperature values corresponding to the input temperature profile at a series of times and a series of input temperature values to calculate a series of heating element temperature differential values; c) based on the series of heating element temperature differential values and the first series at a series of times The wire temperature differential value is used to derive a series of temperature compensation values. The device of claim 18, wherein the device is configured to: a) receive a bond wire temperature signal corresponding to a bond wire temperature of the bond wire; b) compare the bond wire temperature signal to the input a temperature signal; c) compensating for the first series of bond wire temperature differential values based on a comparison of the bond wire temperature signal to the input temperature signal; and d) deriving a second series of compensated bond wire temperature differential values. The device of claim 19, wherein the device is configured to apply a multiplier gain to the first series of bond wire temperature differential values to obtain the second series of compensated bond wire temperature differential values. The apparatus of claim 16, wherein the apparatus is configured to: compare the temperature compensation curve with a predetermined series of power settings for applying heat to the heating element; and based on the predetermined series A power set value of the power setpoint produces a temperature compensated power signal.