Heating device and method for manufacturing soldered object

Abstract

A heating device and a method for manufacturing a soldered object that have a relatively simple configuration and that suppress the occurrence of temperature unevenness within an allowable range in both the temperature rising process and the temperature maintaining process are provided. [Solution] The heating device 1 includes a support member 18 that supports an object to be heated, and a heater 20 that heats the object to be heated supported by the support member 18 or the support member 18 that supports the object to be heated. The heater 20 has multiple annular heating elements 20P, each with a different circumferential length and arranged in a nested configuration, and is capable of outputting different amounts of heat from one another, and the amount of heat output is changeable. A method for manufacturing a solder-joined object using the heating device 1 includes supplying the object to be heated to the support member 18, causing the heating elements 20P to generate heat and raise the temperature of the object to a first predetermined temperature, changing the output ratio of the heating elements 20P to maintain the first predetermined temperature, supplying a reducing gas, increasing the output of the heating elements 20P to raise the temperature to a second predetermined temperature, and performing solder bonding.

Description

[Technical Field]

[0001] The present disclosure relates to a heating device and a method for manufacturing a soldered object. [Background technology]

[0002] In a reflow soldering device for soldering a substrate, there is a device that prevents temperature unevenness, where the temperature at the edges of the plate is lower than that at the center when the substrate placed on the plate is heated by heating the plate. This reflow soldering device radiates heat to the plate on which the substrate is placed by arranging multiple parallel, coarsely wound infrared lamp heaters in which the filament is wound sparsely in the center in the longitudinal direction and densely at both ends (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2024-106687 Summary of the Invention [Problem to be solved by the invention]

[0004] During the process of raising a substrate from a relatively low temperature to a predetermined temperature (e.g., a temperature suitable for reducing oxides on the substrate), the proportion of heat dissipation from the outer surface of the plate tends to be smaller than during the process of maintaining the predetermined temperature after heating. In other words, the heat dissipation ratio between the center and outer portions of the plate changes between the heating and maintaining temperature. Since the winding density of the filament of a densely wound infrared lamp heater cannot be changed during use, the output ratio between the center and the end portions is predetermined. Therefore, in a reflow soldering machine using a densely wound infrared lamp heater, it is difficult to suppress temperature unevenness within an acceptable range during both the heating and maintaining temperature processes, where the heat dissipation characteristics of the plate differ. While it is possible to install a heater that changes output between the heating and maintaining temperature processes separately from the densely wound infrared lamp heater, this would result in a complex and large-sized device.

[0005] In view of the above-mentioned problems, the present disclosure relates to providing a heating device and a method for manufacturing a solder-joined object that have a relatively simple configuration and that suppress the occurrence of temperature unevenness within an acceptable range during both the temperature increase process and the temperature maintenance process. [Means for solving the problem]

[0006] A heating device according to a first aspect of the present disclosure includes a support member that supports an object to be heated, and a heater that heats the object to be heated supported by the support member or the support member that supports the object to be heated, the heater having a plurality of annular heating elements, each of which has a different circumferential length and is arranged in a nested manner, and which is capable of outputting different amounts of heat from each other and is capable of changing the amount of heat output.

[0007] With this configuration, the output of the heating element can be changed separately for the outside and inside in accordance with the amount of heat required, with a relatively simple configuration, and the occurrence of temperature unevenness can be suppressed.

[0008] Furthermore, as a heating device according to a second aspect of the present disclosure, in the heating device according to the first aspect of the present disclosure, the support member may be a plate-like member on which the object to be heated is placed, and the heater may heat the plate-like member.

[0009] With this configuration, when a plurality of heating objects with different reflectivities are heated in sequence, it is possible to suppress variations in the amount of energy required to raise the heating objects to a predetermined temperature.

[0010] Furthermore, as a heating device according to a third aspect of the present disclosure, in the heating device according to the first or second aspect of the present disclosure, at least one of the heating elements may be divided in the circumferential direction.

[0011] With this configuration, the temperature controllable region can be subdivided, enabling finer temperature control.

[0012] Furthermore, a heating device according to a fourth aspect of the present disclosure may be a heating device according to any one of the first to third aspects of the present disclosure, which is provided with a control device that controls the output of each of the heating elements.

[0013] With this configuration, the output of each heating element can be adjusted depending on the condition of the object to be heated.

[0014] Furthermore, as a heating device according to a fifth aspect of the present disclosure, in the heating device according to the fourth aspect of the present disclosure, the control device may control the output of each of the heating elements so that the output of the outer heating elements is equal to or greater than the output of the inner heating elements, and so that the output of the outermost heating element is greater than the output of the innermost heating element.

[0015] With this configuration, the output of the heating element can be increased toward the outside where heat is relatively easily dissipated, and it is possible to prevent the temperature from dropping on the outside compared to the inside of the object to be heated.

[0016] Furthermore, as a heating device according to a sixth aspect of the present disclosure, in the heating device according to the fourth or fifth aspect of the present disclosure, the control device may increase the ratio of the output of the outer heating element to the output of the inner heating element when it determines that the temperature of the object to be heated has reached a predetermined temperature.

[0017] With this configuration, it is possible to suppress the occurrence of temperature unevenness when, for example, the process shifts from the temperature increasing process to the temperature maintaining process.

[0018] A method for manufacturing a solder-jointed object according to a seventh aspect of the present disclosure is a method for manufacturing an object that has been solder-jointed using the heating device according to the fifth aspect of the present disclosure, and includes the steps of: supplying the object to be heated having solder to the support member; causing the heating element to generate heat to raise the temperature of the object to be heated to a first predetermined temperature, wherein the first predetermined temperature is lower than the melting point of the solder and is a temperature at which oxides present in the object to be heated can be reduced; after the temperature of the object to be heated has risen to the first predetermined temperature, increasing the ratio of the output of the outer heating element to the output of the inner heating element to maintain the temperature of the object to be heated at the first predetermined temperature; supplying a reducing gas to the object to be heated that is maintained at the first predetermined temperature; and after the reducing gas has been supplied to the object to be heated, increasing the output of the heating element to raise the object to a second predetermined temperature that is higher than the melting point of the solder and thereby performing solder joining.

[0019] With this configuration, the object to be heated can be heated evenly, and a soldered object with good solder joints can be produced. [Effects of the Invention]

[0020] According to the present disclosure, with a relatively simple configuration, the output of the heating element can be changed separately for the outside and inside according to the amount of heat required, thereby suppressing the occurrence of temperature unevenness. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view showing a schematic configuration of a reflow apparatus according to an embodiment of the present disclosure. [Figure 2] 1 is a schematic plan view of a reflow apparatus according to an embodiment of the present disclosure. [Figure 3] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. [Figure 4] 1 is a flowchart showing a procedure for manufacturing a solder-bonded substrate according to an embodiment of the present disclosure. [Figure 5] 1A is a schematic plan view of a reflow soldering apparatus according to a first modified example of an embodiment of the present disclosure, and FIG. 1B is a schematic plan view of a reflow soldering apparatus according to a second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, identical or similar reference numerals are used to designate identical or corresponding components, and redundant explanations will be omitted. Furthermore, the dimensions and proportions of the drawings are exaggerated for the sake of explanation and may differ from the actual proportions.

[0023] First, a reflow apparatus 1 according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 3. FIG. 1 is a perspective view showing a schematic configuration of the reflow apparatus 1. FIG. 2 is a schematic plan view of the reflow apparatus 1. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. The reflow apparatus 1 is an apparatus primarily used for solder bonding. The solder bonding referred to here includes forming solder bumps on a substrate and mounting electronic components on the substrate having the solder bumps. When forming solder bumps on a substrate, a substrate having solder material arranged on its surface is heated inside the reflow apparatus 1. The solder material melts, and when the molten solder cools and solidifies, it typically forms hemispherical solder bumps. On the other hand, when mounting electronic components on a substrate, an electronic component is placed on the solder bumps of the substrate on which the solder bumps have been formed, and the substrate is heated inside the reflow apparatus 1. The solder bumps melt, and the molten solder cools and solidifies, soldering the electronic component to the substrate. In this way, the reflow apparatus 1 heats the board having solder thereon, and so the reflow apparatus 1 can be said to be one form of a heating apparatus. First, the configuration of the reflow apparatus 1 will be described below.

[0024] In this embodiment, the reflow apparatus 1 includes a chamber 10, a plate 18, a heater 20, support pins 31, and a control device 60. Note that Fig. 1 shows a state in which the lid 14 of the chamber 10 is open. Fig. 2 shows the arrangement of the lid 14 and the plate 18 with dashed lines to show the configuration and arrangement of the heater 20. Fig. 3 shows a state in which the lid 14 is closed.

[0025] The chamber 10 forms a processing space 11 (see FIG. 3) in which a substrate W (see FIG. 3) is processed. The substrate W is an example of an object to be soldered, and corresponds to an object to be heated because it is the object to be processed, including heating. The substrate W corresponds to what is generally called a workpiece (sometimes simply abbreviated as "work"), and in this embodiment, it will be described as being formed in a circular, plate-like shape (hereinafter referred to as "disk-shaped"). In this embodiment, since a disk-shaped substrate W is handled, the plate 18 that supports the substrate W is also formed in a circular shape. The chamber 10 has a floor 12, a wall 13, and a lid 14.

[0026] The floor 12 is a member that constitutes the floor of the processing space 11. The floor 12 is a thick plate-like member formed to a size that can accommodate the plate 18. In this embodiment, the floor 12 has a circular shape in a plan view, but may also have a rectangular or other polygonal shape. As shown in FIG. 3 , the floor 12 has grooves 12G that accommodate the heaters 20. Therefore, the floor 12 has a thickness that allows the grooves 12G to be formed. In this embodiment, the floor 12 has cooling blocks 12C provided between adjacent grooves 12G. The cooling blocks 12C typically cool the plate 18 by at least one of heat transfer and heat radiation. The cooling blocks 12C typically have cooling fluid flow paths (not shown) on their surface and / or inside, through which a cooling fluid flows, and are cooled by heat exchange with the cooling fluid.

[0027] The wall 13 is a member that forms the wall of the processing space 11. The wall 13 is made of a thick plate-like member, and has a hole 13H formed therein in a plan view. The hole 13H is large enough to accommodate the plate 18 and be encompassed by the floor 12. In other words, in this embodiment, the hole 13H is formed in a circular shape that is larger than the plate 18 and smaller than the floor 12. The floor 12 is connected to the bottom surface of the wall 13 so as to close the bottom of the hole 13H, thereby forming an open processing space 11 inside the hole 13H. In other words, the inner surface of the hole 13H becomes the wall surface of the processing space 11. Therefore, the height required for the wall surface of the processing space 11 can be determined by the thickness of the thick plate-like member that forms the wall 13. In this embodiment, a rectangular plate-like member is used as the thick plate-like member that forms the wall 13. However, plate-like members having shapes other than a rectangle, such as a polygonal, circular, or elliptical shape, may also be used.

[0028] The lid 14 is a plate-like member that closes the open upper surface of the processing space 11, which is formed by the floor 12 and the wall 13. The lid 14 is large enough to encompass the hole 13H, and in this embodiment, a plate-like member that is circular in plan view is used. The lid 14 can be attached to and detached from the wall 13, and when the lid 14 is attached to the wall 13, the processing space 11 is typically sealed. The attachment and detachment of the lid 14 to and from the wall 13 is typically performed automatically by an opening and closing device (not shown), but may also be configured to be performed manually by an operator.

[0029] The plate 18 is a member on which the substrate W is placed. The plate 18 can support the substrate W placed on its upper surface and corresponds to a support member. In this embodiment, a circular, flat member is used as the plate 18. The circular shape of the plate 18 allows for a smaller volume and a smaller heat capacity than, for example, a rectangular plate large enough to contain the substrate W. Furthermore, the processing space 11 can be made cylindrical, thereby reducing the volume inside the chamber 10 (i.e., the processing space 11). The surface of the plate 18 on which the substrate W is placed (hereinafter referred to as the "substrate placement surface") is large enough to contain the entire substrate W. A carbon plate made of carbon is typically used as the plate 18 in order to quickly respond to temperature changes when heated or cooled. The carbon plate may be made of graphite. Alternatively, the plate 18 may be made of a metal such as copper, stainless steel, or steel plate. Similarly, from the viewpoint of quickly responding to temperature changes when heated or cooled, the plate 18 is preferably formed as thin as possible (i.e., as small in volume) within the range that still ensures strength, in order to reduce heat capacity. Furthermore, the plate 18 preferably has a flat substrate mounting surface so as to maximize the contact area with the substrate W.

[0030] The heater 20 is a device for heating the substrate W. In this embodiment, the heater 20 directly heats the plate 18 supporting the substrate W and indirectly heats the substrate W through heat transfer from the heated plate 18. In this embodiment, as most clearly shown in FIG. 2 , the heater 20 has multiple heating tubes: a first heating tube 21, a second heating tube 22, a third heating tube 23, a fourth heating tube 24, and a fifth heating tube 25. When referring to the common configuration or characteristics of these multiple heating tubes 21, 22, 23, 24, and 25, they will be collectively referred to as heating tubes 20P. The heating tubes 20P emit heat and correspond to heating elements. In this embodiment, the heating tubes 20P convert input power into heat. Typically, infrared lamp heaters (sometimes referred to as IR heaters) are used, but other heaters such as resistance heaters may also be used. In this embodiment, the heating tubes 20P are formed in an annular shape.

[0031] The first heated pipe 21, the second heated pipe 22, the third heated pipe 23, the fourth heated pipe 24, and the fifth heated pipe 25 each have a different diameter (and also a circumferential length) of the annular shape, and are arranged concentrically in this embodiment. The diameter of the first heated pipe 21 is larger than the diameter of the second heated pipe 22. The diameter of the second heated pipe 22 is larger than the diameter of the third heated pipe 23. The diameter of the third heated pipe 23 is larger than the diameter of the fourth heated pipe 24. The diameter of the fourth heated pipe 24 is larger than the diameter of the fifth heated pipe 25. With this configuration, the first heated pipe 21, the second heated pipe 22, the third heated pipe 23, the fourth heated pipe 24, and the fifth heated pipe 25 are arranged in a nested manner, that is, arranged inside the annular shape in the order listed here. Each heated pipe 20P is arranged in a groove 12G formed in the bed body 12. In other words, the groove 12G is formed at a position where each heated pipe 20P can be arranged in a nested manner as described above. The depth of the groove 12G is approximately the same as the thickness of the heating pipe 20P (that is, the length of the heating pipe 20P in a cross section perpendicular to the longitudinal direction thereof).

[0032] The outputs of the first heated pipe 21, the second heated pipe 22, the third heated pipe 23, the fourth heated pipe 24, and the fifth heated pipe 25 can be set independently, i.e., they can output different amounts of heat. Furthermore, the amount of heat output by each heated pipe 20P can be changed. With this configuration, for example, the more outer the heated pipe 20P is located, the greater the output can be, and the difference in output between the inner heated pipe 20P and the outer heated pipe 20P can be changed over time.

[0033] In this embodiment, the first heated pipe 21, the second heated pipe 22, and the third heated pipe 23 are divided in the circumferential direction. This suppresses the occurrence of temperature differences depending on the position in the circumferential direction (or length direction) of the heated pipe 20P. In this embodiment, the first heated pipe 21, which has a relatively long circumferential length, is divided into four equal parts in the circumferential direction, and the second heated pipe 22 and the third heated pipe 23, which have shorter circumferential lengths than the first heated pipe 21, are divided into two equal parts in the circumferential direction. Note that although the fourth heated pipe 24 and the fifth heated pipe 25 are not divided in the circumferential direction, they are not infinitely continuous rings but have an end portion interrupted at one location in the circumferential direction. Each heated pipe 20P is bent toward the bed body 12 at the divided or interrupted end in the circumferential direction, penetrates the bed body 12, and is connected to a power source (not shown) outside the chamber, typically via a lead wire.

[0034] The support pins 31 are members that support the underside of the plate 18. Each support pin 31 is formed in the shape of a long, thin rod. The support pins 31 are arranged to extend vertically and support the plate 18 at their upper ends. The support pins 31 are typically fixed to the underside of the plate 18, but may also be supported by simply contacting the underside of the plate 18. In this embodiment, six support pins 31 are provided, each consisting of three pairs, to support the outer periphery of the circular plate 18 at appropriate intervals. The two support pins 31 in each pair are typically positioned so that an imaginary line connecting them passes through the center of the circular plate 18. However, the number and arrangement of the support pins 31 can be changed as needed, depending on, for example, the size and shape of the plate 18. Each support pin 31 can reciprocate up and down by actuation of a drive source (not shown). The drive source (not shown) is typically an electric actuator, but an actuator using fluid pressure (e.g., hydraulic or pneumatic) may also be used. Each support pin 31 is arranged to penetrate the floor structure 12. In other words, the floor body 12 has through holes through which the support pins 31 pass. A sealing measure (not shown) is provided around each support pin 31 that passes through the through hole in the floor body 12, so that the processing space 11 can be kept sealed even when each support pin 31 moves in the axial direction (i.e., up and down). As each support pin 31 moves up and down, the plate 18 can move up and down between a position in contact with the cooling block 12C and a position spaced above the cooling block 12C.

[0035] In addition to the above-described configuration, the reflow apparatus 1 according to this embodiment also includes a gas supply unit 40, as shown in FIG. 3. The gas supply unit 40 supplies nitrogen gas N as an inert gas and formic acid gas F as a reducing gas to the processing space 11 for use in processing the substrate W. The gas supply unit 40 includes a supply pipe 41, a nitrogen pipe 43, and a formic acid pipe 45. One end (or a first end) of the supply pipe 41 penetrates the bed body 12 and opens into the processing space 11. The other end (or a second end) of the supply pipe 41 is connected to one end (or a first end) of the nitrogen pipe 43 and one end (or a first end) of the formic acid pipe 45. The other end (or a second end) of the nitrogen pipe 43 is connected to a nitrogen source (not shown) that supplies nitrogen gas N. The nitrogen pipe 43 is provided with a nitrogen valve 44 that opens and closes the flow path. The other end (or second end) of the formic acid pipe 45 is connected to a formic acid source (not shown) that supplies formic acid gas F. The formic acid pipe 45 is provided with a formic acid valve 46 that opens and closes the flow path. The gas supply unit 40 does not supply gas to the processing space 11 when the nitrogen valve 44 and the formic acid valve 46 are closed. The gas supply unit 40 supplies nitrogen gas N to the processing space 11 by opening the nitrogen valve 44 with the formic acid valve 46 closed, and supplies formic acid gas F to the processing space 11 by opening the formic acid valve 46 with the nitrogen pipe 43 closed. In this embodiment, nitrogen gas N or formic acid gas F is selectively supplied to the processing space 11 via the supply pipe 41, but nitrogen gas N and formic acid gas F may be supplied to the processing space 11 via separate systems. In other words, the supply pipe 41 may be omitted, and one end (or first end) of the nitrogen pipe 43 and one end (or first end) of the formic acid pipe 45 may each be individually opened into the processing space 11.

[0036] As shown in FIG. 3 , the reflow apparatus 1 according to this embodiment also includes an exhaust unit 50. The exhaust unit 50 exhausts gas from the processing space 11 to the outside of the chamber 10. The exhaust unit 50 includes an exhaust pipe 51, a vacuum pump 52, and an exhaust valve 53. The exhaust pipe 51 is a pipe that forms a flow path for directing gas from the processing space 11 to the outside of the system. The exhaust pipe 51 penetrates the floor 12 or the wall 13 as shown in the figure, and one end (or a first end) of the exhaust pipe 51 opens into the processing space 11. The other end (or a second end) of the exhaust pipe 51 is connected to an exhaust treatment device (not shown). The exhaust treatment device (not shown) treats the gas exhausted from the processing space 11 to a level that allows it to be released into the atmosphere. The vacuum pump 52 is a device that pumps the gas from the processing space 11 to the outside and creates a negative pressure in the processing space 11 by exhausting the gas from the processing space 11. The vacuum pump 52 is provided in the exhaust pipe 51. The exhaust valve 53 is a member that can block the flow path of the exhaust pipe 51, allowing the flow of gas when open and blocking the flow of gas when closed. In this embodiment, the exhaust valve 53 is provided in the exhaust pipe 51 between the chamber 10 and the vacuum pump 52. Typically, the exhaust unit 50 keeps the vacuum pump 52 running all the time while the reflow apparatus 1 is in operation, and switches between evacuating the processing space 11 and not evacuating it by opening and closing the exhaust valve 53, but the vacuum pump 52 may also be started and stopped in conjunction with the opening and closing of the exhaust valve 53.

[0037] The control device 60 is a device that controls the operation of the reflow apparatus 1. The control device 60 is connected to an opening / closing device (not shown) that opens and closes the lid 14 of the chamber 10 via a communication line (wired or wireless; the same applies below). The control device 60 opens and closes the lid 14 by operating the opening / closing device (not shown). The control device 60 is also connected to the heater 20 via a communication line and individually controls the output of each heating tube 20P. The control device 60 is also connected to a drive source (not shown) that operates the support pins 31 via a communication line and controls the direction and amount of movement of the support pins 31 (and thus the plate 18) by operating the drive source (not shown). The control device 60 is also individually connected to the nitrogen valve 44 and the formic acid valve 46 of the gas supply unit 40 via communication lines and individually controls the opening and closing of the nitrogen valve 44 and the formic acid valve 46. The control device 60 is also connected to the vacuum pump 52 of the exhaust unit 50 via a communication line and controls the start and stop of the vacuum pump 52. The control device 60 is also connected to the exhaust valves 53 via a communication line, and individually controls the opening and closing of the exhaust valves 53. The control device 60 also has a timer, and measures any desired time.

[0038] 3, the control device 60 may include at least one physical configuration of a processor 61, a memory 62 (e.g., RAM and / or ROM), and a storage 63. The control device 60 may also have a program for properly operating each of the above-mentioned devices stored in, for example, the memory 62 and / or the storage 63, and may execute the program using the processor 61. This program may include a sequence program that determines the sequence and timing of operations of each of the above-mentioned devices. The control device 60 is typically attached to the outer surface of the chamber 10, but may also be installed in a location remote from the chamber 10 to remotely operate the reflow apparatus 1.

[0039] Next, a method for manufacturing a soldered substrate will be described with reference to FIG. 4. The soldered substrate is a substrate W on which soldering has been performed, and corresponds to a soldered object. FIG. 4 is a flowchart showing the steps for manufacturing a soldered substrate. The method for manufacturing a soldered substrate described below is carried out using the reflow apparatus 1 described above. The following description of the method for manufacturing a soldered substrate using the reflow apparatus 1 also includes a description of the operation of the reflow apparatus 1. In the following description, when the configuration of the reflow apparatus 1 is mentioned, reference will be made to FIGS. 1 to 3 as appropriate. The operation of each device connected to the control device 60 via a communication line, as described below, is typically controlled by the control device 60, unless otherwise noted.

[0040] When the reflow apparatus 1 is stopped, the nitrogen valve 44 and the formic acid valve 46 are closed, the vacuum pump 52 is stopped, and the exhaust valve 53 is closed. When manufacturing a solder-bonded substrate begins, a substrate W having solder is first placed on the plate 18 (S1). Placing the substrate W on the plate 18 is one form of supplying the substrate W to the plate 18. When placing the substrate W on the plate 18, it is preferable to place the substrate W so that its centroid coincides with the centroid of the plate 18. This centroid coincidence does not require strict coincidence; it is sufficient if the centroids coincide to the extent that the temperature unevenness when the substrate W is heated in a later process is within an acceptable range. Once the substrate W is placed on the plate 18, the lid 14 of the chamber 10 is closed. Closing the lid 14 seals the processing space 11 within the chamber 10.

[0041] Next, the control device 60 starts the vacuum pump 52 and alternately opens and closes the exhaust valve 53 and the nitrogen valve 44 to replace the gas in the processing space 11 with nitrogen gas N (S2). In this embodiment, the exhaust valve 53 first opens, and when the pressure in the processing space 11 is reduced to about 100 Pa (absolute pressure), the exhaust valve 53 closes. Thereafter, the nitrogen valve 44 opens, and when nitrogen gas N flows into the processing space 11, the nitrogen valve 44 closes. This is repeated once or several times to replace the gas in the processing space 11 with nitrogen gas N.

[0042] Next, the control device 60 activates the support pins 31, which raises the plate 18, setting the plate 18 to the heating position (S3). The heating position is a position where the temperature of the substrate W placed on the plate 18 is set to a temperature higher than the ambient temperature of the reflow apparatus 1, and is a position where the plate 18 is separated from the cooling block 12C. By separating the plate 18 from the cooling block 12C, it is possible to prevent the plate 18 from being cooled by heat transfer from the cooling block 12C during heating.

[0043] Once the plate 18 is set in the heating position, the control device 60 activates the heater 20 to begin heating the substrate W (S4). The heating here aims to heat the substrate W to a reduction temperature. The reduction temperature is a temperature below the melting point of the solder contained in the substrate W and suitable for reducing oxides present in the solder-containing substrate W in the presence of a reducing gas, and corresponds to the first predetermined temperature. In this embodiment, since formic acid gas F is used as the reducing gas, the reduction temperature is, for example, 180°C to 220°C (typically about 200°C), and may have a range. In this process of raising the temperature of the substrate W to the reduction temperature, the control device 60 controls the output of each of the nested heating tubes 20P so that the output of the outer heating tube 20P is equal to or greater than the output of the inner heating tube 20P, and so that the output of the outermost heating tube 20P (i.e., the first heating tube 21) is greater than the output of the innermost heating tube 20P (i.e., the fifth heating tube 25). This is a measure to suppress temperature unevenness of the plate 18 and thus the substrate W during heating, based on the finding that when the entire plate 18 and therefore the substrate W are heated uniformly, the outside tends to dissipate heat more easily and become lower in temperature than the inside. The difference or ratio of the outputs between the heating tubes 20P should be set so as to minimize temperature unevenness of the heated substrate W, taking into consideration the characteristics of the reflow apparatus 1 and the substrate W. In this embodiment, whether the substrate W has been heated to the reducing temperature by heating in this heating step is estimated by determining in advance the time required for the substrate W to reach the reducing temperature under the heating conditions, and heating the substrate W under those conditions for the predetermined time.

[0044] Once the temperature of the substrate W has risen to the reducing temperature, the controller 60 adjusts the output of each heating tube 20P to maintain the temperature of the substrate W at the reducing temperature (S5). In this temperature maintaining step, the substrate W that has risen to the reducing temperature is maintained at that temperature, i.e., the temperature of the substrate W needs not to drop, so the output of the heater 20 is typically smaller than the output in the temperature increasing step (S4). In the step (S5) of maintaining the temperature of the substrate W at the reducing temperature, the controller 60 controls the output of each heating tube 20P so that the output of the outer heating tube 20P is equal to or greater than the output of the inner heating tube 20P, while increasing the ratio of the output of the outer heating tube 20P to the output of the inner heating tube 20P compared to the temperature increasing step (S4). This is a measure to suppress temperature unevenness of the plate 18 and, ultimately, the substrate W that is maintained at the reducing temperature, based on the finding that the proportion of heat dissipated from the outside is greater in the temperature maintaining step (S5) than in the temperature increasing step (S4). The difference or ratio of the outputs between the heating pipes 20P should be set in consideration of the characteristics of the reflow apparatus 1 and the substrate W so that the temperature unevenness of the substrate W maintained at the reduction temperature is minimized.

[0045] Furthermore, once the temperature of the substrate W has risen to the reduction temperature, the control device 60 opens the exhaust valve 53 to exhaust the gas inside the processing space 11 (S6). At this time, it is preferable to reduce the pressure inside the processing space 11 to approximately 50 Pa to 100 Pa (absolute pressure) so that substantially all of the gas inside the processing space 11 is exhausted. Here, "substantially all of the gas inside the processing space 11" means that substances other than the formic acid gas F are exhausted so that the formic acid gas F inside the processing space 11 will have a desired concentration when the formic acid gas F is introduced into the processing space 11 in a later step. In this embodiment, the time required to exhaust the gas inside the processing space 11 is calculated in advance, and when a predetermined time has elapsed since the exhaust valve 53 was opened, the control device 60 closes the exhaust valve 53. Note that in the example shown in FIG. 4, the step (S5) of adjusting the output of each heating tube 20P to maintain the temperature of the substrate W at the reduction temperature and the step (S6) of exhausting the gas inside the processing space 11 are performed in this order. However, the step (S5) of maintaining the temperature of the substrate W at the reducing temperature and the step (S6) of discharging the gas inside the processing space 11 may be performed simultaneously. Alternatively, the order in which these steps (S5, S6) are started may be reversed as appropriate.

[0046] While maintaining the temperature of the substrate W at the reduction temperature, the controller 60 opens the formic acid valve 46 to allow formic acid gas F to flow into the processing space 11 (S7). When formic acid gas F flows into the processing space 11, oxides are reduced in the substrate W heated to the reduction temperature. In this embodiment, the plate 18 and therefore the substrate W are maintained at a generally uniform temperature overall, so that oxide reduction is carried out evenly and appropriately. In addition, in this embodiment, the time required for oxide reduction to be completed under the conditions for oxide reduction (temperature of the substrate W, concentration of formic acid gas F in the processing space 11, etc.) is determined in advance, and the controller 60 determines the completion of reduction when the predetermined time has elapsed.

[0047] When the reduction of oxides on the substrate W is completed, the control device 60 alternately opens and closes the exhaust valve 53 and the nitrogen valve 44 to replace the gas in the processing space 11 with nitrogen gas N (S8). The procedure for replacing the gas with nitrogen gas N here is the same as the above-mentioned step of replacing the gas with nitrogen gas N (S2).

[0048] Once the replacement with nitrogen gas N is complete, the control device 60 increases the output of the heater 20 to start heating the substrate W (S9). The temperature increase here aims to heat the substrate W to the melting temperature of the solder. The melting temperature is a temperature equal to or higher than the melting point of the solder contained in the substrate W, is a temperature suitable for soldering, and corresponds to the second predetermined temperature. In this embodiment, the melting temperature is, for example, 230°C to 270°C (typically about 250°C), and may vary. In this step of raising the temperature of the substrate W to the melting temperature, the control device 60 typically sets the output of each heating pipe 20P to the same value as the output in the step (S4) of raising the temperature of the substrate W to the reduction temperature. This is because the proportion of external heat radiation is smaller in the temperature increase step than in the temperature maintenance step. In consideration of the fact that the melting temperature is higher than the reducing temperature, the output of each heating tube 20P may be made larger than that in the reducing temperature raising step (S4) while maintaining the output ratio between the heating tubes 20P as in the reducing temperature raising step (S4). As in the reducing temperature raising step (S4), in this embodiment, whether the substrate W has risen to the melting temperature through heating in this step is estimated by determining in advance the time required for the substrate W to reach the melting temperature under the heating conditions, and heating the substrate W under those conditions for the predetermined time. When the temperature of the substrate W rises to the melting temperature, the solder present on the substrate W melts and soldering is performed.

[0049] Once the board W is soldered, the control device 60 stops the heater 20, thereby stopping heating of the board W (S10). When the heater 20 stops, the temperature of the plate 18, and therefore the board W, begins to drop. In this embodiment, to accelerate the temperature drop of the board W, after heating of the board W is stopped, the control device 60 activates the support pins 31, which lowers the plate 18 and sets the plate 18 to the cooling position (S11). Here, the cooling position is a position where the temperature of the board W placed on the plate 18 approaches the ambient temperature of the reflow apparatus 1, and is typically a position where the plate 18 is in contact with the cooling block 12C. When the temperature of the board W drops below the solidification temperature of the molten solder, the solder solidifies, and a soldered board is produced. Once the soldered board is produced, the lid 14 of the chamber 10 is opened at any time, and the soldered board is removed from the chamber 10 (S12). This completes the manufacturing of the soldered substrate.

[0050] As described above, the reflow soldering apparatus 1 according to this embodiment has the following advantages. Each of the heating tubes 20P has a different diameter (i.e., circumferential length) and is nested. The heating tubes 20P can output different amounts of heat, and the amount of heat output can be adjusted. This allows the output to be adjusted according to the required amount of heat, thereby suppressing temperature unevenness. Furthermore, the heating tubes 20P, which have a relatively large circumferential length, are divided circumferentially. This allows the temperature-controllable region to be subdivided, enabling more precise temperature control. Furthermore, during temperature rise, the output of the outer heating tubes 20P is set to be equal to or greater than the output of the inner heating tubes 20P, and the output of the first heating tube 21 is set to be greater than the output of the fifth heating tube 25. This allows the output of the heating tubes 20P to be increased toward the outside, where heat dissipation is easier, thereby suppressing temperature unevenness. Furthermore, when the reduction temperature begins to be maintained, the ratio of the output of the outer heating tubes 20P to the output of the inner heating tubes 20P is increased, thereby suppressing temperature unevenness when transitioning from the temperature rise process to the temperature maintenance process.

[0051] In the above description, each heating tube 20P is formed in a circular ring shape, but the shape is not limited to a circular ring shape and may be, for example, an elliptical ring shape, or a polygonal ring shape such as a triangle, a square (including a rectangle and a diamond), a pentagon, a hexagon, or an octagon. As an example, Fig. 5(A) and Fig. 5(B) show an embodiment in which each heating tube 20P is in a rectangular ring shape.

[0052] The heater 20A shown in the schematic plan view of FIG. 5(A) has a first heated pipe 21A, a second heated pipe 22A, a third heated pipe 23A, a fourth heated pipe 24A, and a fifth heated pipe 25A, each of which is formed in a rectangular ring shape. Like each heated pipe 20P in the heater 20 (see FIG. 2), these multiple heated pipes 21A, 22A, 23A, 24A, and 25A and the corresponding heated pipes shown in FIG. 5(B) described below will also be collectively referred to as heated pipes 20P when referring to a common configuration or characteristic. Each heated pipe 20P in the heater 20A according to this modification is configured similarly to each corresponding heated pipe 20P in the heater 20 (see FIG. 2), except that the shape and the manner of division are different, including the fact that the output can be set and changed independently.

[0053] The first heated pipe 21A, the second heated pipe 22A, the third heated pipe 23A, the fourth heated pipe 24A, and the fifth heated pipe 25A have different circumferential lengths but similar shapes, and are typically arranged in a nested manner so that their centroids coincide. Each heated pipe 20P in the heater 20A is divided circumferentially near the midpoint of one of two pairs of opposing sides. The divided pairs of sides in each heated pipe 20P in the heater 20A are staggered so that adjacent heated pipes 20P are shifted by 90 degrees. The heater 20A configured in this manner is suitable for use when the plate 18 (see FIG. 1) is rectangular and is also suitable for processing rectangular substrates W (see FIG. 3). When the heater 20A is used, the floor 12, the hole 13H in the wall 13, and the lid 14 shown in FIG. 3 should also be rectangular.

[0054] The heater 20B shown in the schematic plan view of FIG. 5(B) has a first heated pipe 21B, a second heated pipe 22B, a third heated pipe 23B, a fourth heated pipe 24B, and a fifth heated pipe 25B, each of which is formed in a rectangular ring shape, and these are collectively referred to as heated pipes 20P. Each heated pipe 20P in the heater 20B according to this modification is configured in the same way as each heated pipe 20P in the heater 20A (see FIG. 5(A)), except that the manner of division in the circumferential direction is different. Each heated pipe 20P in the heater 20B is divided in the circumferential direction at the four corners of the rectangle. Therefore, each heated pipe 20P in the heater 20B is divided into four equal parts. With the configuration of the heater 20B according to this modification, a straight pipe without bends can be used for the divided parts of each heated pipe 20P, and the configuration can be simplified.

[0055] In the above description, the reflow apparatus 1 is described as being equipped with the chamber 10, but if it is not necessary to form the processing space 11 when processing the substrate, the chamber 10 need not be provided (i.e., it can be omitted). In this case, it is sufficient to have a configuration equivalent to the floor body 12 on which the heater 20 is installed. Also, in the above description, the reflow apparatus 1 is described as being equipped with the gas supply unit 40 and the exhaust unit 50, but if at least one of the gas supply unit 40 and the exhaust unit 50 is not used, the unused configuration need not be provided (i.e., it can be omitted).

[0056] In the above description, the first heated pipe 21, the second heated pipe 22, the third heated pipe 23, the fourth heated pipe 24, and the fifth heated pipe 25, each having an annular shape and different diameters, are arranged concentrically, but the centers may be offset as long as they are arranged in a nested manner. Similarly, the centroids of the rectangular heated pipes 20P in the heaters 20A and 20B may be offset as long as they are arranged in a nested manner.

[0057] In the above description, it has been assumed that the first heated pipe 21 is divided into four parts in the circumferential direction, the second heated pipe 22 and the third heated pipe 23 are divided into two parts in the circumferential direction, and the fourth heated pipe 24 and the fifth heated pipe 25 are not divided into parts in the circumferential direction. However, whether or not each heated pipe 20P is divided into parts in the circumferential direction, and the number of parts to be divided into if divided, can be determined appropriately depending on the purpose. For example, the number of parts to be divided into in the circumferential direction of the heated pipe 20P is not limited to two or four, and may be three, five, six, eight, or any other number of parts. Furthermore, the mode of division is not limited to equal division, and may be divided at a desired ratio. The same applies to each heated pipe 20P in the heaters 20A and 20B.

[0058] In the above description, the inert gas supplied by the gas supply unit 40 is nitrogen gas N, and the reducing gas is formic acid gas F. However, the inert gas may be other than nitrogen gas N, such as argon gas. Furthermore, the reducing gas may be a carboxylic acid gas other than formic acid, hydrogen gas, or the like.

[0059] In the above description, whether the substrate W has reached the reducing temperature or melting temperature in the temperature-raising step is estimated by heating the substrate W under the relevant conditions for a predetermined period of time. However, a sensor for detecting the temperature of the substrate W or the plate 18 may be provided, and the determination may be made based on the temperature detected by the sensor.

[0060] In the above description, the multiple heating pipes 20P constituting the heater 20 have different circumferential lengths, are arranged nested, and are capable of outputting different amounts of heat from one another, and the amount of heat output is changeable. This configuration of the heater 20 may also be applied to a cooler, and for example, the cooling blocks 12C may have different circumferential lengths, are arranged nested, and are capable of outputting different amounts of cold heat (i.e., amounts of cooled heat or amounts of heat that can be removed) from one another, and the amount of cold heat output may be changeable. The same applies to the heaters 20A and 20B.

[0061] In the above description, the configuration corresponding to the support member is the plate 18 that supports the entire lower surface of the substrate W, but it may also be a jig such as an outer edge holding chuck or frame that supports all or part of the edge of the substrate W. In this case, radiant heat from the heaters 20, 20A, 20B is directly irradiated onto the substrate W.

[0062] In each of the above embodiments, the term "processor" refers to a processor in a broad sense, and includes general-purpose processors (e.g., CPU: Central Processing Unit, etc.) and dedicated processors (e.g., GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, programmable logic device, etc.). Furthermore, the operations of the processor in each of the above embodiments may be performed not only by a single processor but also by multiple processors located at physically separate locations working together. Furthermore, the order of the operations of the processor is not limited to the order described in each of the above embodiments and may be changed as appropriate. The program may be provided by a computer-readable non-transitory recording medium such as a USB (Universal Serial Bus) memory, a flexible disk, or a CD-ROM (Compact Disc Read Only Memory), or may be provided online via a network such as the Internet. In this case, the program recorded on the computer-readable non-transitory recording medium is typically transferred to and stored in a memory or storage device. The program may be provided as standalone application software, or may be incorporated into the software of each device as a function of the device. The program of the present disclosure can be provided as a program product. The program product includes any product for providing the program. For example, the program product includes a program provided over a network such as the Internet, and a non-transitory computer-readable recording medium such as a CD-ROM or DVD on which the program is stored.

[0063] In the above description, the reflow apparatus 1 as a heating apparatus and the method for manufacturing a solder-joined object have been described as exemplary embodiments using the drawings. The configuration, structure, number, arrangement, shape, material, etc. of each part in the description are not limited to the above specific examples, and any suitable alternatives selected by a person skilled in the art are also included within the scope of the present invention as long as they include the gist of the present invention. [Explanation of symbols]

[0064] 1 Reflow equipment (heating equipment) 18 Plate (support member) 20, 20A, 20B heater 20P Heating tube (heating element) 60 Control device W substrate (heating object)

Claims

1. a support member for supporting an object to be heated; a heater for heating the object to be heated that is supported by the support member, or the support member that supports the object to be heated, the heater having a plurality of annular heating elements, each of the plurality of heating elements having a different circumferential length and arranged in a nested manner, capable of outputting different amounts of heat from one another, and the amount of heat to be outputted being changeable; The heating element includes a first heating element, a second heating element having a circumferential length shorter than that of the first heating element, and a third heating element having a circumferential length shorter than that of the second heating element, the third heating element having an end portion interrupted at one point in the circumferential direction, the second heating element being divided in the circumferential direction, and the first heating element being divided in the circumferential direction into a greater number of portions than the second heating element. heating device.

2. a support member for supporting an object to be heated; a heater for heating the object to be heated that is supported by the support member, or the support member that supports the object to be heated, the heater having a plurality of rectangular annular heating elements, each of the plurality of heating elements having a different circumferential length and arranged in a nested manner, capable of outputting different amounts of heat from one another and capable of changing the amount of heat to be output; Each of the plurality of heating elements is divided in the circumferential direction near the midpoint of one pair of opposing sides of the two sets of opposing sides, and the divided pairs of sides are staggered so that there is a 90-degree difference between adjacent heating elements. heating device.

3. a support member for supporting an object to be heated; a heater for heating the object to be heated that is supported by the support member, or the support member that supports the object to be heated, the heater having a plurality of rectangular annular heating elements, each of the plurality of heating elements having a different circumferential length and arranged in a nested manner, capable of outputting different amounts of heat from one another and capable of changing the amount of heat to be output; Each of the plurality of heating elements is divided in the circumferential direction at four corners of a rectangle. heating device.

4. the support member is a plate-like member on which the object to be heated is placed, The heater heats the plate-like member. The heating device according to any one of claims 1 to 3.

5. A control device is provided to control the output of each of the heating elements. The heating device according to any one of claims 1 to 3.

6. the control device controls the outputs of the outer heating elements so that the outputs of the outer heating elements are equal to or greater than the outputs of the inner heating elements, and so that the output of the outermost heating element is greater than the output of the innermost heating element. The heating device according to claim 5 .

7. When the control device determines that the temperature of the object to be heated has reached a predetermined temperature, the control device increases the ratio of the output of the outer heating element to the output of the inner heating element. The heating device according to claim 5 .

8. a support member for supporting an object to be heated; a heater for heating the object to be heated that is supported by the support member, or the support member that supports the object to be heated, the heater having a plurality of annular heating elements, each of the plurality of heating elements having a different circumferential length and arranged in a nested manner, capable of outputting different amounts of heat from one another and capable of changing the amount of heat to be output; a control device for controlling the output of each of the heating elements; When the control device determines that the temperature of the object to be heated has reached a predetermined temperature, the control device increases the ratio of the output of the outer heating element to the output of the inner heating element. heating device.

9. At least one of the heating elements is divided in the circumferential direction. The heating device according to claim 8.

10. A method for manufacturing a soldered object using the heating device according to claim 6, comprising the steps of: supplying the heating object having solder to the support member; a step of increasing the temperature of the object to be heated to a first predetermined temperature by generating heat from the heating element, the first predetermined temperature being lower than the melting point of the solder and being a temperature at which oxides present in the object to be heated can be reduced; After the temperature of the object to be heated has risen to the first predetermined temperature, increasing the ratio of the output of the outer heating element to the output of the inner heating element to maintain the temperature of the object to be heated at the first predetermined temperature; supplying a reducing gas to the object to be heated that is maintained at the first predetermined temperature; and after the reducing gas is supplied to the object to be heated, increasing the output of the heating element to raise the temperature of the object to a second predetermined temperature equal to or higher than the melting point of the solder, thereby performing solder bonding. A method for manufacturing a soldered object.

11. a support member for supporting an object to be heated; a heater for heating the object to be heated that is supported by the support member, or the support member that supports the object to be heated, the heater having a plurality of annular heating elements, each of the plurality of heating elements having a different circumferential length and arranged in a nested manner, capable of outputting different amounts of heat from one another and capable of changing the amount of heat to be output; a control device for controlling the output of each of the heating elements; a control device controlling an output of each of the heating elements so that an output of each of the outer heating elements is equal to or greater than an output of each of the inner heating elements, and so that an output of the outermost heating element is greater than an output of the innermost heating element, supplying the heating object having solder to the support member; a step of increasing the temperature of the object to be heated to a first predetermined temperature by generating heat from the heating element, the first predetermined temperature being lower than the melting point of the solder and being a temperature at which oxides present in the object to be heated can be reduced; After the temperature of the object to be heated has risen to the first predetermined temperature, increasing the ratio of the output of the outer heating element to the output of the inner heating element to maintain the temperature of the object to be heated at the first predetermined temperature; supplying a reducing gas to the object to be heated that is maintained at the first predetermined temperature; and after the reducing gas is supplied to the object to be heated, increasing the output of the heating element to raise the temperature of the object to a second predetermined temperature equal to or higher than the melting point of the solder, thereby performing solder bonding. A method for manufacturing a soldered object.

Images