IR non-contact temperature detection in dispensers

Abstract

To provide an apparatus and a process for dispensing material, and more specifically, an apparatus and a process for dispensing solder paste in a dispenser.SOLUTION: A dispensing system (10) includes: an optional pre-heat station configured to receive an electronic substrate 12; dispense stations (14, 18) configured to dispense material onto the electronic substrate received from the optional pre-heat station; an optional post-heat station configured to receive the electronic substrate from the dispense station; and a non-contact sensor (212) positioned above the electronic substrate on at least one of the optional pre-heat station, the dispense station and the optional post-heat station.SELECTED DRAWING: Figure 2

Description

Technical Field

[0004] ,

[0003] , , ,

[0001] [Related Applications] This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 62 / 792,087, filed Jan. 14, 2019, entitled “IR Non-Contact Temperature Sensing in a Dispenser,” which is hereby incorporated by reference in its entirety, and this application also claims priority to U.S. Patent Application No. 15 / 831,800, filed Dec. 5, 2017, entitled “Material Temperature Sensor for Stencil Printer,” which is hereby incorporated by reference in its entirety.

[0002] This disclosure relates to apparatuses and processes for dispensing materials, and more particularly, to apparatuses and processes for dispensing solder paste within a dispenser.

Background Art

[0003] There are several types of dispensing systems used to dispense accurate amounts of liquid or paste for a variety of applications. One such application is assembling integrated circuit chips and other electronic components onto circuit boards. In this application, an automated dispensing system is used to dispense dots of liquid epoxy resin, or solder paste, or some other related material onto a circuit board. The automated dispensing system is also used to dispense lines of underfill material and encapsulant that can be used to mechanically secure components to the circuit board. Exemplary dispensing systems described above include those manufactured and distributed by ITW EAE of Glenview, Ill., under the trademark CAMALOT(™).

[0004] In a typical dispensing system, the pump and / or dispenser assembly is mounted on a mobile assembly or gantry, which moves the pump and dispenser assembly along three mutually orthogonal axes (X, Y, and Z axes) using servo motors controlled by a computer system or controller. To dispense a dot of liquid to a desired location on a circuit board or other substrate, the pump and dispenser assembly is moved along the horizontal X and Y axes on the same plane until it is positioned above the desired location. In one embodiment, the pump and / or dispenser assembly is then lowered along the vertical Z axis until the nozzle / needle of the pump and dispenser assembly is positioned at the appropriate dispensing height above the electronic substrate. The pump and / or dispenser assembly dispenses a dot of liquid, is then raised along the Z axis, moved along the X and Y axes towards a new location, and lowered along the Z axis to dispense the next dot of liquid. In another embodiment, the material is ejected from the pump and dispenser assembly without raising or lowering the nozzle / needle of the pump and dispenser assembly. In the sealing or underfill applications described above, the pump and dispenser assembly is typically controlled to dispense the material line as the pump and dispenser assembly moves along the desired path of the line in the X and Y axes.

[0005] It is known that IR temperature sensors are used to monitor the temperature of the solder paste supply cartridge in stencil printers, motivated by the need to ensure that the paste has reached the appropriate temperature for print deposition to proceed. Similarly, the application of material temperature sensing in the pump and dispenser assemblies of dispensing systems is known, motivated by the need to ensure that materials stored at a temperature lower than the appropriate application temperature have actually warmed up to the appropriate temperature for deposition. [Overview of the Initiative]

[0006] One aspect of the present disclosure relates to a dispensing system comprising: an optional preheating station configured to house an electronic substrate; a dispensing station configured to dispense material onto an electronic substrate received from the optional preheating station; an optional postheating station configured to house an electronic substrate from the dispensing station; and a non-contact sensor positioned above the electronic substrate on at least one of the optional preheating station, the dispensing station, and the optional postheating station.

[0007] Embodiments of the dispensing system may further include a non-contact sensor positioned above the electronic substrate on an optional preheating station to ensure the electronic substrate is at an appropriate temperature before being moved to the dispensing station. The non-contact sensor may be mounted on an adjustable mechanism that moves toward and away from a temperature measurement target. The non-contact sensor may be positioned above the dispensing station to ensure the electronic substrate is at an appropriate temperature at the dispensing station. The non-contact sensor may be mounted on an adjustable mechanism associated with the dispensing station. The non-contact sensor may be positioned above the electronic substrate on an optional postheating station to ensure the electronic substrate is at an appropriate temperature at the optional postheating station. The non-contact sensor may be an infrared temperature sensor.

[0008] Another aspect of the present disclosure relates to a dispensing system configured to dispense a viscous assembly material onto an electronic substrate. In one embodiment, the dispensing system comprises a conveyor configured to move a plurality of electronic substrates through the dispensing system; a dispensing station including a dispensing unit configured to dispense a viscous assembly material onto one electronic substrate; and a sensor coupled to the dispensing unit, configured to measure the temperature of the electronic substrate.

[0009] Embodiments of the dispensing system may further include a sensor, which is a non-contact sensor. The non-contact sensor may be an infrared sensor. The non-contact sensor can be fixed to the dispensing unit by an adjustable bracket. The adjustable bracket may be configured to orient the non-contact sensor at a certain angle with respect to the orientation of the electronic substrate.

[0010] A further aspect of the present disclosure relates to a method for printing an assembly material onto an electronic substrate. In one embodiment, the method includes delivering an electronic substrate to a dispensing system, positioning the electronic substrate at a print location, dispensing a viscous assembly material onto the electronic substrate, and measuring the temperature of the electronic substrate.

[0011] Embodiments of the method may further include providing temperature feedback for an electronic substrate as part of a temperature control system. Providing temperature feedback may include the temperature control system turning off heating to the electronic substrate when the electronic substrate reaches a desired target temperature, and turning on heating when the temperature falls below a lower limit temperature. Measuring the temperature of the electronic substrate can be achieved by a sensor. The sensor may be a non-contact sensor. The non-contact sensor may be an infrared sensor. The method may further include positioning the non-contact sensor relative to the electronic substrate by an adjustable bracket.

[0012] Various aspects of at least one embodiment are discussed below with reference to the accompanying drawings. These drawings are not intended to be drawn to a uniform scale. The drawings are included to illustrate and further understand the various aspects and embodiments and are incorporated into this specification, forming part of this specification, but are not intended to define any limitation to any particular embodiment. The drawings, together with the rest of this specification, serve to illustrate the principles and operation of the described and claimed aspects and embodiments. In the drawings, each identical or substantially identical component shown in different drawings is represented by the same reference numeral. For clarity, not all components are labeled in every drawing. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic diagram of the dispensing system. [Figure 2] This is a perspective view of the dispensing system with the packing removed to reveal the preheating station, dispensing station, and postheating station. [Figure 3] This figure shows the graphical user interface ("GUI") of the infrared ("IR") detection configuration graphics related to the preheating station and postheating station. [Figure 4] This is a diagram showing the GUI of the IR detection configuration related to the dispensing station. [Figure 5] This is a diagram showing the GUI of process programming graphics. [Figure 6] This is a diagram showing the GUI of process programming graphics. [Figure 7] This is a diagram showing the GUI of the process monitoring graphics. [Figure 8] This is a diagram showing the GUI of the process monitoring graphics. [Figure 9] This is a flowchart illustrating the operation of the IR detection command. [Figure 10] This is a diagram showing the GUI for the IR detection command graphic. [Figure 11] This is a diagram showing the GUI for the heating options graphic. [Figure 12] This is a diagram showing the GUI of the heating controller graphic. [Modes for carrying out the invention]

[0014] For illustrative purposes only and not to limit its universality, the present disclosure is described in detail here with reference to the accompanying drawings. The present disclosure is not limited to the details of configurations and arrangements of components described below or shown in the drawings in terms of its applications. The principles described herein are also applicable to other embodiments and can be practiced or implemented in various ways. Furthermore, the expressions and terms used herein are for illustrative purposes only and should not be considered limiting. Any reference herein to an example, embodiment, component, element or operation of a system or method referred to singularly may also encompass embodiments containing multiple components, and any reference herein to any embodiment, component, element or operation as plural may also encompass embodiments containing only one component. References in singular or plural form are not intended to limit the systems or methods, their components, operations or elements disclosed herein. The use herein of the terms “including,” “equipped with,” “having,” “containing,” “accompanying,” and variations thereof means that the articles listed before them, their equivalents and additional articles, are included. A reference to “or / or” can be interpreted as comprehensive, such that any term described using “or / or” can refer to one, two or more, or all of the terms described. In addition, if there is inconsistency in the use of terms between this specification and any document that constitutes part of this specification by reference, the use of terms in the document that constitutes this specification is supplementary to the use in this specification, and the use of terms in this specification shall prevail if the inconsistency is contradictory.

[0015] This disclosure relates to detecting not only the temperature of the material being deposited, but also the temperature of the electronic substrate on which the material is deposited. For example, it is known in the SMT assembly industry that electronic substrates in dispensers are often preheated before the underfill material is deposited. A typical application utilizes what is known as a preheating "chuck" (an area or zone that heats the electronic substrate to a predetermined temperature) before the electronic substrate is transported into the dispensing zone to hold the material to be dispensed. The problem with the preheating zone is that there is typically only one feedback sensor that measures the temperature of the entire preheating chuck, which is typically 330 mm × 250 mm. This feedback from a single sensor generally detects the temperature of one location, and the result is assumed to represent the temperature of the entire preheating zone, and not necessarily reflect the actual temperature of a particular location of interest, e.g., the temperature of a critical component. Furthermore, without feedback of the actual temperature of a particular location on the electronic substrate, the time allocated to preheating the electronic substrate is often chosen to ensure that at least a sufficient amount of time has elapsed for the temperature of the electronic substrate to stabilize. This could mean that valuable time is wasted by waiting for an excessively long "sufficient" amount of time.

[0016] Embodiments of the present disclosure include a non-contact sensor positioned above an electronic substrate on a preheating chuck to verify that the electronic substrate is actually at the appropriate temperature before proceeding with a dispensing operation, without having to wait longer than necessary to ensure that the electronic substrate reaches a predetermined temperature. The actual temperature of a critical location can be measured by mounting the non-contact temperature sensor over a specific location on the electronic substrate. Furthermore, the temperature of any specific spot can be measured by mounting the sensor on a dispensing unit (or other mechanism such as a visual probe in a printer) that can move across the electronic substrate in the X-axis and Y-axis directions. The sensor can also be mounted on a mechanism that moves toward and away from a temperature measurement target, or the target can move in the X-axis, Y-axis, and Z-axis directions relative to the sensor. Such configurations allow the effective spot size of the sensor to be adjusted or adjusted to suit the needs of the application. For example, the sensor can be mounted on a vertical stage and oriented to look down on the electronic substrate. The temperature of smaller localized spots can be measured by moving the vertical stage and sensor downward, and therefore closer to the electronic substrate. By moving the vertical stage and sensor upwards, and therefore away from the electronic substrate, the temperature to be measured can be effectively averaged over a larger area. This can also be achieved by moving the target to a specific location relative to the sensor and achieving a specific spot size. Such a configuration allows for the detection of averaged temperature over a controllable size area where the size of the detection area can be optimized for application requirements. Thus, both the location and spot size can be controlled, for example, by mounting the sensor on a Z-axis stage attached to an XY positioning system from a pump mounting bracket.

[0017] By implementing the principles of the present disclosure, it is possible to monitor the temperature of the material dispensed by a piece of equipment and the temperature at important locations on the electronic substrate onto which the material is dispensed, ensuring that all participants in the deposition process are at the desired temperature. Each of these measured temperatures can be utilized to confirm that the process variables are within a preset range before proceeding with the deposition process. Further (or perhaps alternatively), these measurements can be shared or stored for data collection such as statistical process control (SPC) where the quality or yield of the process can be correlated with measured variables within the process for process optimization.

[0018] For purposes of illustration, embodiments of the present disclosure will now be described with reference to a dispensing system generally designated 〖10〗 in accordance with one embodiment of the present disclosure. Referring to FIG. 1, the dispensing system 〖10〗 is used to dispense a viscous material (e.g., an adhesive, encapsulant, epoxy resin, solder paste, underfill material, etc.) or a semi-viscous material (e.g., solder flux, etc.) onto an electronic substrate 〖12〗 such as a printed circuit board (〖"PCB"〗) or semiconductor wafer. The dispensing system 〖10〗 can alternatively be used in other applications such as for applying automotive gasket material, or for application in certain medical fields, or for applying conductive ink, etc. It should be understood that references to viscous or semi-viscous materials herein are illustrative and are intended to be non-limiting. The dispensing system 〖10〗 includes a number of dispensing units, such as a first dispensing unit and a second dispensing unit generally designated 〖14〗 and 〖16〗 respectively, and a controller 〖18〗 that controls the operation of the dispensing system.Please understand that the dispensing unit may also be referred to herein as a dispensing pump and / or a dispensing head. Although two dispensing units are shown, it should be understood that three or more dispensing units can be utilized.

[0019] The dispensing system 10 may also include a frame 20 having a base or support 22 for supporting the electronic substrate 12, a dispensing unit gantry 24 movably coupled to the frame 20 for supporting and moving dispensing units 14, 16, and a weighing device or weighing instrument 26 for weighing the amount of viscous material dispensed and providing weight data to the controller 18, for example, as part of a calibration procedure. To control the mounting and detachment of the electronic substrate to the dispensing system, the dispensing system 10 may use other transfer mechanisms such as a conveyor system (not shown) or a moving beam. The gantry 24 can be moved using motors under the control of the controller 18 to position the dispensing units 14, 16 in predetermined locations above the electronic substrate. The dispensing system 10 may also include a display unit 28 connected to the controller 18 to display various information to the operator. An optional second controller for controlling the dispensing units may be provided. Each dispensing unit 14, 16 may also be configured to use a Z-axis sensor to detect the height at which the dispensing unit is positioned above the electronic substrate 12 or above a mechanism mounted on the electronic substrate. The Z-axis sensor is coupled to the controller 18 and relays the information acquired by the sensor to the controller.

[0020] Before performing the dispensing operation as described above, an electronic substrate, e.g., a printed circuit board, must be aligned or otherwise positioned with respect to the dispensing unit of the dispensing system. The dispensing system further includes a vision system 30. In one embodiment, the vision system 30 is coupled to a vision system gantry 32, and the vision system gantry 32 is movably coupled to the frame 20 to support and move the vision system. In another embodiment, the vision system 30 may be provided on the dispensing unit gantry 24. As described above, the vision system 30 is utilized to collate the locations of landmarks or components known as fiducials on the electronic substrate. Once located, the controller can be programmed to manipulate the movement of one or more of the dispensing units 14, 16 to dispense material onto the electronic substrate.

[0021] In one embodiment, the dispensing operation is controlled by a controller 18, and the controller 18 may include a computer system configured to control the material dispensing unit. In another embodiment, the controller 18 may be operated by an operator. The controller 18 is configured to manipulate the movement of the vision system gantry 32 to move the vision system to acquire one or more images of the electronic substrate 12. The controller 18 is further configured to manipulate the movement of the dispensing unit gantry 24 to move the dispensing units 14, 16 to perform the dispensing operation.

[0022] Referring to Figure 2, the dispensing system is denoted as 200 overall. As shown in the figure, the dispensing system 200 comprises a dispensing station denoted as 202 overall, a preheating station denoted as 204 overall and located upstream of the dispensing station, and a postheating station denoted as 206 overall and located downstream of the dispensing station. The preheating station 204 defines the preheating zone of the dispensing system 200, the dispensing station 202 defines the dispensing zone of the dispensing system 200, and the postheating station 206 defines the postheating zone of the dispensing system 200. A conveyor 208 is provided to move electronic substrates, such as substrates 12, from the preheating station 204 to the dispensing station 202 and the postheating station 206 (from left to right in Figure 2). As shown in the figure, the conveyor 208 includes two lanes 208A and 208B to allow the substrates to enter the dispensing station more efficiently and at a faster rate. The preheating station 204 is configured to heat the electronic substrate to an acceptable temperature for dispensing at the dispensing station. The preheating station 204 can be configured to raise the temperature of the electronic substrate between 20°C and 200°C. The postheating station 206 is configured to lower the temperature of the electronic substrate before it is passed from the dispensing system 200 to another processing station downstream. Similar to the preheating station 204, the postheating station can be configured to lower the temperature of the electronic substrate in the range of 20°C to 200°C.

[0023] In one embodiment, the preheating station 204 and the postheating station 206 may be part of a dispensing system 200 that includes a dispensing station 202. In another embodiment, the dispensing system 200 may be configured to include only the dispensing station 202, and the preheating station 204 and / or postheating station 206 may be separate units assembled together with the dispensing system, with the conveyor 208 extending through all three stations.

[0024] The preheating station 204 is equipped with an adjustable bracket, generally shown as 210, which is mounted on the conveyor 208 at a high position covering the conveyor lanes 208A and 208B. As shown in the figure, the adjustable bracket 210 is positioned to cover the electronic circuit board as it moves along the conveyor lanes 208A and 208B through the preheating station 204. For each lane 208A and 208B, an infrared sensor 212 is mounted on the adjustable bracket 210 and positioned to be directed toward the electronic circuit board as it moves along the conveyor lane beneath the adjustable bracket and infrared sensor. The adjustable bracket 210 of the preheating station 204 can be configured to move each infrared sensor 212 in the X-axis, Y-axis, and Z-axis directions.

[0025] In one embodiment, the adjustable bracket 210 includes a first rail member 214 extending over lane 208A and a second rail member 216 extending over lane 208B. The first rail member 214 includes a first support member 218 configured to rest along a track formed within the first rail member. A first thumbscrew 220 is provided to secure the first support member 218 to the first rail member 214 in order to lock the first support member in place. An infrared sensor 212 is mounted on the free end of the first support member 218. Similarly, the second rail member 216 includes a second support member 222 configured to rest along a track or slot formed within the second rail member. A second thumbscrew 224 is provided to secure the second support member 222 to the second rail member 216 in order to lock the second support member in place. The infrared sensor 212 is mounted on the free end of the second support member 222. The position of the infrared sensor 212 can be adjusted by unlocking the thumb screws 220 and 224 and moving the first support member 218 and the second support member 222, respectively, to the desired position.

[0026] For each lane 208A, 208B, the actual temperature of a critical location on the electronic circuit board can be measured by mounting an infrared sensor 212 to cover a specific location on the electronic circuit board as it moves along the lane. The adjustable bracket 210 is configured to move each infrared sensor 212 toward and away from the temperature measurement target in the Z-axis direction, and to position the infrared sensor in the X-axis and Y-axis directions. Such a configuration allows the effective spot size of the infrared sensor to be adjusted or adjusted to suit the needs of the application. As described above, the infrared sensor 212 can be oriented to look down on the electronic circuit board. By operating the adjustable bracket 210 to lower the infrared sensor 212 closer to the electronic circuit board, the temperature of a smaller local spot can be measured. Conversely, by operating the adjustable bracket 210 to raise the infrared sensor 212 away from the electronic circuit board, the temperature of a larger spot can be measured, thereby effectively averaging over a larger area. Such a configuration allows for the detection of an averaged temperature over a controllable size area where the size of the sensing area can be optimized for application requirements.

[0027] Similarly, the post-heating station 206 is equipped with an adjustable bracket, generally shown as 230, which is identical to the adjustable bracket 210 of the pre-heating station 204, and is mounted on the conveyor 208 at a high position that covers the electronic circuit board, such as the electronic circuit board 12, as the electronic circuit board moves along the conveyor lanes 208A and 208B through the post-heating station. For each lane 208A and 208B, an infrared sensor 212, identical to the infrared sensor used in the pre-heating station 204, is mounted on the adjustable bracket 230 and positioned so as to be directed toward the electronic circuit board as the electronic circuit board moves beneath the adjustable bracket and infrared sensor. The adjustable bracket 230 of the post-heating station 206 can be configured to move each infrared sensor 212 in the X-axis, Y-axis, and Z-axis directions.

[0028] As described above, in one embodiment, the adjustable bracket 230 is identical to the adjustable bracket 210 and includes a third rail member 234 extending over lane 208A and a fourth rail member 236 extending over lane 208B. The third rail member 234 includes a third support member 238 configured to rest along a track or slot formed within the third rail member. A third thumbscrew 240 is provided to secure the third support member 238 to the third rail member 234 in order to lock the third support member in place. An infrared sensor 212 is mounted on the free end of the third support member 238. Similarly, the fourth rail member 236 includes a fourth support member 242 configured to rest along a track formed within the fourth rail member. A fourth thumb screw 244 is provided to secure the fourth support member 242 to the fourth rail member 236 in order to lock the fourth support member in place. An infrared sensor 212 is mounted on the free end of the fourth support member 242. The position of the infrared sensor 212 can be adjusted by disengaging the third thumb screw 240 and the fourth thumb screw 244 and moving the third support member 238 and the fourth support member 242 to the desired positions.

[0029] In one embodiment, the dispensing station 202 further comprises an infrared sensor 212 mounted on or directly on the carriage 250 supporting the dispensing unit 252. Thus, the infrared sensor 212 is moved by the gantry in the X-axis, Y-axis, and Z-axis directions. The infrared sensor 212 can operate to ensure that the electronic substrate is at an appropriate temperature for dispensing when it is positioned within the dispensing station 202 on lane 208A or 208B of the conveyor 208. As described above, with respect to the preheating station 204 and the postheating station 206, the dispensing station can be configured to raise, maintain, and / or lower the temperature of the electronic substrate between 20°C and 200°C.

[0030] Alternatively, in another embodiment, the infrared sensor 212 may be mounted on a visual system gantry, such as the visual system gantry 32 of the dispensing system 10, to move the infrared sensor in the X-axis, Y-axis, and Z-axis directions. Similar to the dispensing system 10, the dispensing system 200 may comprise two or more dispensing units, and the infrared sensor 212 may be mounted on one of the dispensing units.

[0031] Therefore, infrared sensing is used for non-contact temperature tracking across components on electronic circuit boards transported by a conveyor. Temperature sensing allows operators to monitor and record the temperature of the circuit board in each process zone (up to six) within the machine. Preheating and postheating zones use infrared sensors mounted on adjustable brackets, within which the infrared sensors are positioned and locked in place. Dispensing zones (which may be multiple) use infrared sensors mounted on cartridges and / or dispensing units, so the configuration is flexible in terms of location, as it is set in the process program.

[0032] For each process zone, the operator selects the target temperature and tolerance range that the product must reach to be considered "ready." "Ready" can mean that the product can move to the next conveyor zone, or, if in the dispensing zone, is "ready" for the dispensing process to begin. Another objective is to maintain the substrate in a "ready" state, so when at a given temperature, the machine automatically adjusts the heating settings to maintain the product within the desired tolerance range.

[0033] Referring to Figure 3, which shows the graphical user interface, or GUI300, infrared (IR) detection of the electronic substrate temperature can be configured through dedicated software for all three zones: the preheating zone, the dispensing zone, and the postheating zone. Within these zones, IR detection is achieved by non-contact thermal sensors and electronic substrate clamping, and can be configured through the execution software for both single-lane and dual-lane machines.

[0034] Referring to Figure 4, which shows GUI400, both preheating detection and postheating detection can be configured using non-contact thermal detection. The dispensing station configuration includes an option to enable IR detection.

[0035] While creating a new process program, the operator can individually program temperature settings for each program under the Temperature tab. Under the Temperature tab, the operator checks the "Use Temperature Settings from Process Program" option to override the temperature settings from the machine configuration. The alarm status changes from "Using Machine Config Parameters" to "Using Process Program Parameters." If a process requires heating, the "Heat Required" option can be checked to ensure that no process program runs without proper heating. The software can be configured to sound an alarm in this case.

[0036] Referring to Figure 5, which shows GUI500, the maximum temperature limit for IR detection is 100°C for all three zones: the preheating zone, the dispensing zone, and the postheating zone. The operator has the option to turn IR detection on / off for each zone within the process program. Default values ​​for "Min. Temperature," "Max. Temperature," "Soak Time," "Timeout," and "Polling Rate" are displayed for each zone and are shown in Table 1.

[0037] [Table 1]

[0038] Referring to Figure 6, which shows GUI600, if IR detection is disabled for the preheating zone and / or postheating zone, the heating chucks associated with these zones should be heated using a timer. The preheating and / or postheating duration timer is started to heat the chucks. When the timer finishes, the circulating station air should be switched on and off alternately based on the input value.

[0039] The actual readings from the IR sensor are displayed in real time on the GUI via the data display panel, and represent the desired behavior of the traceable MES function for electronic board handling in each zone, as described below.

[0040] In the preheating zone and / or postheating zone, the process includes placing the electronic circuit board and initiating heating. Once the minimum temperature is reached, the immersion time begins. While immersed or waiting to move, heating cycles on and off as the temperature reaches the minimum or maximum pre-designed temperature. When the immersion time ends and the next zone becomes available, the electronic circuit board moves, and an alarm is triggered if the electronic circuit board does not enter the designated range before the timeout period ends. For recovery, the steps are retry, abort, or release to the next zone. If the operator does not perform error recovery during an error condition, the electronic circuit board may be heated to the maximum temperature. To avoid this effect, the software is configured to display an alarm, pause the machine, circulate station air, and continue measuring the electronic circuit board temperature until the operator performs error recovery.

[0041] In the dispensing zone, the process includes housing the electronic circuit board and measuring its temperature. If the temperature is not within a predetermined range, heating is initiated until it reaches the range before the timeout expires. Temperature measurement continues until the temperature is within the predetermined range. Once the temperature is within the range, processing begins immediately. When the dispensing cycle is complete, the electronic circuit board is moved to the next station as quickly as possible. If the operator does not perform error recovery during an error condition, the electronic circuit board may be heated and reach its maximum temperature. To avoid this effect, the software is configured to turn off the station air, issue an alarm, pause the machine, and continue measuring the electronic circuit board temperature until the operator performs error recovery. The process program may have multiple IR detection commands, and IR detections are batched using the dispensing pass. It is possible to detect the electronic circuit board temperature multiple times within the dispensing pass. Only a minimum temperature will exist (there is no maximum temperature). When an IR detection command is activated, dispensing is suspended until the minimum temperature is reached. Alarm times apply to each IR detection command, as with preheating and postheating detections.

[0042] Infrared temperature detection commands can be programmed multiple times at desired locations on the electronic circuit board within the same process program. Chuck temperature, IR detection state timer, electronic circuit board temperature, IR detection state (ramping, immersion, hold), and station air on / off are listed on the data display for easy process monitoring. The station air light on the data display turns green when on and red when off. The status is displayed only when the process program is running.

[0043] Referring to Figure 7, which shows the GUI700 when IR detection is enabled, the timer indicates the duration of the IR detection state (i.e., how long the temperature will ramp up, how long it will be immersed, or how long it will be maintained). The timer resets when the state changes.

[0044] Table 2 shows the different states of IR detection.

[0045] [Table 2]

[0046] Referring to Figure 8, which shows the GUI800 when "Maintain Temp" is selected by the operator, the IR sensor reads the temperature and maintains it between the minimum and maximum by circulating air. The IR sensor behaves in the same way that the preheating station / postheating station currently does.

[0047] Generally, when an electronic circuit board enters the preheating zone, the IR detection state changes as follows: ramping → immersion → complete → maintain.

[0048] Referring to Figure 9, process 900 includes ensuring that the temperature is maintained until the next station becomes available to accept the electronic substrate. As shown in the figure, a determination is made at 902 as to whether the downstream station is available to accept the electronic substrate. If the downstream station is available, the IR detection command is completed at 904 and the operation ends. If the downstream station is not available, the temperature is detected by a non-contact sensor at 906, and a determination is made at 908 as to whether the temperature is within a predetermined range. If the temperature is within the predetermined range, the process returns to determining whether the downstream station is available to accept the electronic substrate. If the temperature is not within the predetermined range, air is circulated on / off at 910 until the process returns to determining whether the downstream station is available to accept the electronic substrate.

[0049] Referring to Figure 10, which shows GUI1000, the operator should place the IR detection command within the main process program when "maintain temperature" is required. If the IR detection command is located inside a call, this feature can be ignored. When using "pass", the operator should assign the last pass to the IR detection command.

[0050] Referring to Figure 11, which shows the GUI1100 during idling, all heating is powered off. The operator can decide to power off all heating, including chuck and needle heating, based on a programmed time in minutes. This function is located under the Temperature tab in the machine configuration and works only in Automatic Mode. The operator can also check the option to disable the heating power-off function during production operation.

[0051] Referring to Figure 12, which shows the GUI1200 at startup, the heating controller is powered on. If the operator checks this option, the heating controller, including up to six chucks and two needle heaters, will be powered on after startup. All heaters will only begin ramping up after the server has started, if the operator left them enabled during the last machine shutdown. If for any reason the server does not start automatically, the heating controller will not be powered on. In that case, the operator must manually start the server to power on the heating controller. This function is located under the Temperature tab in the machine configuration and works in all dispensing modes.

[0052] In one embodiment, the distance at which the non-contact sensor is separated from the electronic substrate depends on the type of non-contact sensor selected. For example, for one type of sensor, the sensor can be separated from the electronic substrate by a distance of 1 millimeter (mm) to 100 mm. In one embodiment, the detection spot size generated by the non-contact sensor corresponds to the distance of the non-contact sensor from the electronic substrate. Therefore, increasing the distance of the non-contact sensor from the electronic substrate increases the detection spot size. Thus, the range for use in a printhead assembly of the embodiments of this disclosure is a distance of 1 mm to 100 mm. In one embodiment, a distance of 25 mm is selected.

[0053] The non-contact sensor is configured to detect the temperature of an electronic circuit board to verify whether the temperature is correct for a specific application, using criteria predetermined by a user setup process in which the operator of the dispensing system inputs settings for the dispensing system before the dispensing operation. The non-contact sensor is connected to a controller and configured to immediately notify the operator if the electronic circuit board is not ready for dispensing. Furthermore, temperature data for one or more electronic circuit boards can be collected by the controller. The collected data can be fed back to the dispensing system for further operation, or the collected data can be transmitted to a data acquisition system such as a downstream machine or to internal or remote statistical processing.

[0054] In a particular embodiment, the non-contact sensor is an infrared sensor that detects the temperature of an electronic substrate. The infrared sensor is an electronic sensor configured to measure infrared light emitted from an object positioned within the sensor's field of view. Objects having a temperature above absolute zero emit heat in the form of radiation. In a particular embodiment, the infrared sensor is the T-GAGE® M18T series infrared temperature sensor supplied by Banner Engineering Corporation, located in Minneapolis, Minnesota. The T-GAGE® sensor is a passive, non-contact, temperature-based sensor used to detect the temperature of an object within a sensing window and to output a proportional voltage or current depending on the sensor configuration.

[0055] Non-contact sensors, such as those positioned above the circuit board on a preheating chuck, can be used to verify that the circuit board is actually at the appropriate temperature before proceeding with the dispensing operation, without having to wait longer than necessary to ensure that the system components are at the appropriate temperature. By mounting the non-contact sensor over a specific location on the circuit board, the actual temperature of that location can be measured. Furthermore, by mounting the sensor on a dispensing unit (or other mechanism such as a visual probe in a printer) that can move across the circuit board in the x and y directions, the temperature of any specific spot within the dispensing station can be measured. The non-contact sensor can also be mounted on a mechanism that moves toward and away from the target of temperature measurement, or the target can move in the x, y, and z directions relative to the sensor. Such configurations allow the effective spot size of the sensor to be adjusted or controlled to suit the needs of the application. For example, the non-contact sensor can be mounted on a vertical stage and oriented to look down on the circuit board. By moving the vertical stage and sensor downward, and therefore closer to the circuit board, the temperature of smaller localized spots can be measured. By moving the vertical stage and sensor upward, and therefore away from the electronic substrate, the temperature to be measured can be effectively averaged over a larger area. This can also be achieved by moving the target to a specific location relative to the sensor and achieving a specific spot size. Such a configuration allows for the detection of averaged temperature over a controllable size area where the size of the detection area can be optimized for application requirements. Thus, by mounting the sensor on a Z-axis stage attached to an XY positioning system, both the location and spot size can be controlled.

[0056] Furthermore (or perhaps alternatively), the measurements can be shared or stored for data collection purposes, such as statistical process control (SPC), where process quality or yield can be correlated with in-process measurement variables for process optimization.

[0057] In another embodiment of the present disclosure, an infrared non-contact temperature sensor is used to provide temperature feedback of the temperature of an electronic substrate as part of a temperature control system. In particular, when the electronic substrate reaches a desired target temperature, commonly referred to as a setpoint temperature, the temperature control system turns off heating to the electronic substrate. Subsequently, when the temperature falls below a lower limit temperature, the temperature control system turns on heating. In some embodiments, the operation of turning heating on or off may be accompanied by enabling or disabling power to the heater. In other embodiments, this operation may be accompanied by enabling or disabling a heat transfer mechanism. For example, in one embodiment of the present invention, air circulates through the surface to be heated and then to the substrate. When the airflow is enabled, heat transfer from the heater to the substrate is increased. When the airflow is disabled, heat transfer from the heater to the substrate is blocked. This simple limit cycle technique can provide sufficient temperature control accuracy for many applications.

[0058] In other embodiments of the present disclosure, an infrared non-contact temperature sensor is used to provide temperature feedback of an electronic substrate temperature as part of a closed-loop temperature control system. In such a system, the controller uses the temperature to be measured and a desired setpoint temperature as inputs to a control algorithm. The algorithm may also have proportional control of a heater, which provides the ability to enable the heater in a number of finer steps between fully on or fully off, as well as enabling or disabling heating. In one embodiment of the present disclosure, a digital proportional / integral / derivative controller, commonly referred to as a PID controller, uses the output of a PID algorithm through pulse-width modulation (PWM) means to vary the on / off duty cycle of the heater. This combination of a PID controller and digital proportional control of a heater can achieve temperature control that is more accurate and can be controlled more precisely than achieved using a limit cycle regulator.

[0059] Having described several aspects of at least one embodiment of the present disclosure, it should be understood that various modifications, changes, and improvements will readily come to mind for those skilled in the art. Such modifications, changes, and improvements are intended to be part of the present disclosure and to be within the spirit and scope of the present disclosure. Accordingly, the foregoing description and drawings are merely illustrative. The above-described embodiments may also be described as follows, but are not limited thereto. [Configuration 1] An optional preheating station configured to house an electronic circuit board, A dispensing station configured to dispense material onto the electronic substrate received from the optional preheating station, An optional post-heating station configured to house the electronic circuit board, A non-contact sensor positioned above the electronic circuit board on at least one of the optional preheating station, the dispensing station, and the optional postheating station, A dispensing system equipped with the following features. [Configuration 2] The dispensing system according to Configuration 1, wherein the non-contact sensor is positioned above the electronic substrate on the optional preheating station to ensure that the electronic substrate is at an appropriate temperature before moving the electronic substrate to the dispensing station. [Configuration 3] The dispensing system according to configuration 2, wherein the non-contact sensor is mounted on an adjustable mechanism that moves toward and away from a target for temperature measurement. [Structure 4] The dispensing system according to configuration 1, wherein the non-contact sensor is positioned above the dispensing station to ensure that the electronic substrate is at an appropriate temperature in the dispensing station. [Composition 5] The dispensing system according to configuration 4, wherein the non-contact sensor is mounted on an adjustable mechanism associated with the dispensing station. [Composition 6] The dispensing system according to configuration 1, wherein the non-contact sensor is positioned above the electronic substrate on the optional post-heating station to ensure that the electronic substrate is at an appropriate temperature on the optional post-heating station. [Composition 7] The dispensing system according to configuration 6, wherein the non-contact sensor is mounted on an adjustable mechanism that moves toward and away from a target for temperature measurement. [Structure 8] The dispensing system according to configuration 1, wherein the non-contact sensor is an infrared temperature sensor. [Composition 9] A dispensing system configured to dispense viscous assembly material onto an electronic substrate, A conveyor configured to move multiple electronic circuit boards through the dispensing system, A dispensing station including a dispensing unit configured to dispense viscous assembly material onto a single electronic substrate, A sensor coupled to the dispensing unit, configured to measure the temperature of the electronic substrate, A dispensing system equipped with the following features. [Configuration 10] The dispensing system according to configuration 9, wherein the sensor is a non-contact sensor. [Composition 11] The dispensing system according to configuration 10, wherein the non-contact sensor is an infrared sensor. [Composition 12] The dispensing system according to configuration 10, wherein the non-contact sensor is fixed to the dispensing unit by an adjustable bracket. [Composition 13] The dispensing system according to configuration 12, wherein the adjustable bracket is configured to orient the non-contact sensor at a certain angle with respect to the orientation of the electronic substrate. [Composition 14] A method for printing assembly materials onto an electronic circuit board, Sending the electronic circuit board to the dispensing system, Positioning the aforementioned electronic circuit board at the print position, Dispensing the viscous assembly material onto the electronic substrate, To measure the temperature of the aforementioned electronic substrate, Methods that include... [Composition 15] The method according to configuration 14, wherein the temperature of the electronic substrate is measured by a sensor. [Composition 16] The method according to configuration 15, wherein the sensor is a non-contact sensor. [Composition 17] The method according to configuration 16, wherein the non-contact sensor is an infrared sensor. [Composition 18] The method according to configuration 16, further comprising positioning the non-contact sensor relative to the electronic substrate by an adjustable bracket. [Composition 19] The method according to configuration 14, further comprising providing temperature feedback for the electronic substrate as part of a temperature control system. [Configuration 20] The method according to configuration 19, wherein providing temperature feedback includes the temperature control system turning off heating to the electronic substrate when the electronic substrate reaches a desired target temperature, and the temperature control system turning on heating when the temperature falls below a lower limit temperature.

Claims

1. A method for dispensing assembly material onto an electronic circuit board, The electronic circuit board is sent to a dispensing system, and the dispensing system is Frame and, A preheating station coupled to the frame and configured to house and heat the electronic circuit board, the preheating station having a first non-contact sensor positioned to measure the temperature of the electronic circuit board, A dispensing station comprising: a dispensing unit gantry coupled to the frame and configured to move in the X-axis and Y-axis directions; at least one dispensing unit coupled to the dispensing unit gantry and configured to move in the Z-axis direction by a carriage, configured to dispense material onto the electronic substrate positioned on a substrate support; and a second non-contact sensor, which is an infrared temperature sensor, positioned above the electronic substrate on the dispensing station and mounted on the carriage to move toward the electronic substrate in the X-axis, Y-axis and Z-axis directions for measuring the temperature of the electronic substrate; Having, Moving the electronic circuit board to the position before dispensing within the preheating station, The first non-contact sensor, positioned above the electronic substrate, measures the temperature of the electronic substrate at the position before dispensing, When the electronic circuit board is at an appropriate temperature, the electronic circuit board is moved to the dispensing position within the dispensing station, Dispensing a viscous assembly material onto the aforementioned electronic substrate, In order to confirm that the electronic substrate is at an appropriate temperature, the temperature of the electronic substrate at the dispensing position is measured by the second non-contact sensor positioned above the electronic substrate, Includes, A method further comprising positioning the first non-contact sensor relative to the electronic substrate by a first adjustable bracket.

2. The method according to claim 1, wherein the first non-contact sensor is an infrared temperature sensor.

3. Moving the electronic substrate to the position after dispensing within the post-heating station, In order to confirm that the electronic substrate is at an appropriate temperature, the temperature of the electronic substrate at the position after dispensing is measured by a third non-contact sensor positioned above the electronic substrate, The method according to claim 1, further comprising:

4. The method according to claim 3, further comprising positioning the third non-contact sensor relative to the electronic substrate by a second adjustable bracket.

5. The method according to claim 1, further comprising providing temperature feedback for the electronic substrate as part of a temperature control system.

6. The method according to claim 5, wherein providing temperature feedback includes the temperature control system turning off heating to the electronic substrate when the electronic substrate reaches a desired target temperature, and the temperature control system turning on heating when the temperature falls below a lower limit temperature.

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