Manufacturing apparatus and manufacturing method for semiconductor devices

Abstract

A semiconductor device manufacturing apparatus and method are disclosed that can appropriately maintain the quality of the semiconductor device. The semiconductor device manufacturing apparatus includes: a stage; a bonding head having a mounting tool, a tool heater mounted on the mounting tool, and a lifting mechanism for moving the mounting tool in a vertical direction; and a controller for performing a bonding process, wherein the controller performs the following in the bonding process: a first process in which, after the chip is placed onto a substrate, heating of the chip is initiated while pressing the chip against the substrate; a deformation elimination process in which, after the first process and before the melting of the bumps, deformation of the bonding head is eliminated by driving the lifting mechanism in an upward direction; and a second process in which, after the deformation elimination process, the position of the lifting mechanism is controlled in a manner that offsets the thermal expansion and contraction of the bonding head, thereby maintaining the gap amount at a predetermined target value.

Description

Technical Field

[0001] This specification discloses a manufacturing apparatus and method for manufacturing a semiconductor device by bonding a chip held by a mounting tool to a substrate. Background Technology

[0002] Since then, flip chip bonding machines have been known as a technique for mounting chips onto a substrate. In a flip chip bonding machine, raised electrodes called bumps are formed on the bottom surface of the chip. Then, the chip is pressed onto the substrate using a mounting tool, and the chip is heated to melt the bumps, thereby bonding the chip's bumps to the substrate's electrodes.

[0003] Patent Document 1 discloses such a flip-chip bonding machine technology. In Patent Document 1, after the chip is placed onto the substrate using a mounting tool, the chip is heated while being pressurized under a certain load to melt the bumps. Furthermore, in Patent Document 1, if the bumps melt, the mounting tool is raised so that the gap between the bottom surface of the chip and the substrate is at a desired value, and then the heater is disconnected to harden the bumps.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 5014151 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, in Patent Document 1, the chip is continuously pressurized with a certain load until the bumps are completely melted. In this case, immediately after the bumps melt, the tip of the mounting tool drops sharply, potentially flattening the molten bumps significantly. In particular, the mounting tool typically deforms when the chip is pressurized with a certain load. If the reaction force from the chip on the mounting tool decreases as the bumps melt, the deformation is instantly eliminated, and the tip of the mounting tool moves in the direction that flattens the molten bumps. As a result, the molten bumps are sometimes flattened to an extent greater than expected. In this case, the flattened bumps expand in the planar direction, potentially causing short circuits between adjacent bumps.

[0009] That is, in the prior art, short circuit defects may occur, making it impossible to properly maintain the quality of the semiconductor device. Therefore, this specification discloses a semiconductor device manufacturing apparatus and manufacturing method that can properly maintain the quality of the semiconductor device.

[0010] Technical means to solve the problem

[0011] The semiconductor device manufacturing apparatus disclosed in this specification includes: a stage, a substrate support; a bonding head, a mounting tool having a mounting tool for holding a chip with bumps on its bottom surface, a tool heater mounted on the mounting tool for heating the chip, and a lifting mechanism for moving the mounting tool in a vertical direction; and a controller for controlling the driving of the bonding head and bonding the chip to the substrate, wherein the controller performs the following in the bonding process: a first process, after the chip is placed on the substrate, driving the tool heater and the lifting mechanism to start heating the chip and simultaneously applying pressure to the chip against the substrate; a deformation elimination process, after the first process and before the bumps melt, eliminating the deformation of the bonding head by driving the lifting mechanism in an upward direction; and a second process, after the deformation elimination process, maintaining the gap between the bottom surface of the chip and the upper surface of the substrate at a predetermined target value by controlling the position of the lifting mechanism in a manner that cancels out the thermal expansion and contraction of the bonding head.

[0012] In this case, the controller may also perform deformation elimination detection processing before the joining process. In the deformation elimination detection processing, while the mounting tool and the platform are kept at a predetermined temperature, the lifting mechanism is driven to press the substrate with the mounting tool. Then, while driving the lifting mechanism in the upward direction, the pressing load of the mounting tool on the substrate is detected, and the amount of movement of the lifting mechanism from the start of driving in the upward direction to the cessation of the change in the pressing load is stored as the deformation elimination amount. In the deformation elimination processing, the lifting mechanism is driven in the upward direction based on the deformation elimination amount.

[0013] Alternatively, the controller may perform a melt time detection process before bonding the chip to the substrate to detect the melting time of the bump. In the melt time detection process, after the chip is placed on the substrate, the chip is heated according to a predetermined temperature distribution, and the time from the start of the heating to the melting of the bump is stored as the melting time. The controller determines the execution time of the deformation elimination process based on the melting time.

[0014] Alternatively, the lifting mechanism may include: a sliding shaft mechanically connected to the installation tool; a drive source for raising and lowering the sliding shaft; and a position sensor for detecting the axial position of the sliding shaft as a detection position. The controller performs a target distribution generation process before the joining process. In the target distribution generation process, the lifting mechanism is driven so that the installation tool lands on the substrate, and the installation tool is heated according to a predetermined temperature distribution. Based on the change in the detection position detected by the position sensor at this time, the thermal expansion of the joint is obtained, and a movement distribution that cancels out the thermal expansion is generated as a target distribution. In the second process, the lifting mechanism is position-controlled according to the target distribution.

[0015] The semiconductor device manufacturing method disclosed in this specification drives a joint head having a mounting tool, a tool heater mounted on the mounting tool, and a lifting mechanism for moving the mounting tool in a vertical direction, thereby bonding a chip held on the mounting tool to a substrate supported on a stage. The semiconductor device manufacturing method includes: a first step, after the mounting tool is lowered to allow the chip to land on the substrate, driving the tool heater and the lifting mechanism to start heating the chip while simultaneously applying pressure to the chip against the substrate; a deformation elimination step, after the first step and before the melting of bumps provided on the bottom surface of the chip, eliminating deformation of the joint head by driving the lifting mechanism in an upward direction; and a second step, after the deformation elimination step, controlling the position of the lifting mechanism in a manner that cancels out the thermal expansion and contraction of the joint head, thereby maintaining the gap between the bottom surface of the chip and the upper surface of the substrate at a predetermined target value.

[0016] The effects of the invention

[0017] According to the technology disclosed in this specification, deformation of the joint is eliminated before the bump melts, and the lifting mechanism is then controlled in a manner that offsets the thermal expansion and contraction of the joint. This prevents the molten bump from being excessively flattened, thus properly maintaining the quality of the semiconductor device. Attached Figure Description

[0018] Figure 1 This is a schematic diagram showing the structure of a semiconductor device manufacturing apparatus.

[0019] Figure 2 This is a schematic diagram illustrating the bonding configuration of semiconductor chips.

[0020] Figure 3 This is a diagram showing the shape of the joint after thermal expansion.

[0021] Figure 4It is a diagram showing the shape of the deformation that occurs at the joint.

[0022] Figure 5 This is a flowchart representing the process of joining.

[0023] Figure 6 It is a graph showing the time changes of various parameters in the bonding process.

[0024] Figure 7 This is a flowchart illustrating the process of detecting and processing the amount of deformation elimination.

[0025] Figure 8 It is a graph showing the time changes of various parameters in the deformation elimination detection process.

[0026] Figure 9 This is a flowchart illustrating the process of detecting and processing melting time points.

[0027] Figure 10 It is a graph showing the time changes of various parameters in the melting time point detection process.

[0028] Figure 11 This is a flowchart representing the process of generating and processing the target distribution.

[0029] Figure 12 It is a graph showing the time changes of various parameters in the target distribution generation process.

[0030] [Explanation of Symbols]

[0031] 10: Semiconductor device manufacturing equipment

[0032] 12: Platform

[0033] 14: Connector

[0034] 16: Controller

[0035] 18: XY platform

[0036] 20: Installation tools

[0037] 24a: Unit 1

[0038] 24b: Unit 2

[0039] 26: Tool heater

[0040] 30: Voice Coil Motor / VCM

[0041] 32: Sliding shaft

[0042] 34: Leaf Spring

[0043] 36: Guiding Components

[0044] 38: Base components

[0045] 40: Lifting motor

[0046] 42: Lead screw

[0047] 44: Moving Block

[0048] 46: Moving body

[0049] 48: Guide rail

[0050] 50: Linear encoder

[0051] 90: Reference Distribution

[0052] 92: Ideal Distribution

[0053] 94: Target Distribution

[0054] 100: Semiconductor chip

[0055] 102: Chip Body

[0056] 104: Bump

[0057] 110: Substrate

[0058] 112: Electrode Detailed Implementation

[0059] Hereinafter, the semiconductor device manufacturing apparatus 10 will be described with reference to the accompanying drawings. Figure 1 This is a schematic diagram showing the structure of a semiconductor device manufacturing apparatus 10. The manufacturing apparatus 10 is an apparatus for manufacturing semiconductor devices by mounting a semiconductor chip 100, which is an electronic component, onto a substrate 110 with its face down. The manufacturing apparatus 10 includes: a connector 14 having a mounting tool 20, a chip supply member (not shown) for supplying the semiconductor chip 100 to the mounting tool 20, a stage 12 supporting the substrate 110, an XY stage 18 for moving the stage 12 in the XY direction (horizontal direction), and a controller 16 for controlling the drive of these components.

[0060] The substrate 110 is held in place by suction on the stage 12 and heated by a stage heater (not shown) provided on the stage 12. Meanwhile, the semiconductor chip 100 is supplied to the mounting tool 20 via a chip supply member. Various structures can be considered for the chip supply member; for example, a structure in which the semiconductor chip is picked up from the wafer placed on the wafer stage using a transfer arm and transferred to a transfer stage. In this case, the XY stage 18 moves the transfer stage directly below the mounting tool 20, and the mounting tool 20 picks up the semiconductor chip from the transfer stage located directly below.

[0061] If the semiconductor chip is picked up by the mounting tool 20, the substrate 110 is then moved directly below the mounting tool 20 via the XY stage 18. If the aforementioned state is achieved, the mounting tool 20 descends toward the substrate 110, pressing and bonding the semiconductor chip 100, which is held at its end, to the substrate 110.

[0062] The mounting tool 20 draws and holds the semiconductor chip 100 while simultaneously heating it. Therefore, the mounting tool 20 is provided with a suction port (not shown) communicating with a vacuum source, or a tool heater 26 for heating the semiconductor chip 100. In addition to the mounting tool 20, the connector 14 is also provided with a lifting mechanism for raising and lowering the mounting tool 20.

[0063] The lifting mechanism in this example is roughly divided into a first unit 24a and a second unit 24b. The first unit 24a moves the mounting tool 20 in the Z-axis direction (i.e., the vertical direction), thereby pressing the semiconductor chip 100 against the substrate 110 and applying a pressing load to the semiconductor chip 100. The first unit 24a has a voice coil motor 30 (hereinafter referred to as "VCM 30"), a sliding shaft 32, a leaf spring 34, and a guide member 36. The VCM 30 is the drive source of the first unit 24a. The VCM 30 has a stator 30a fixed to the moving body 46 and a mover 30b movable in the Z-axis direction relative to the stator 30a. The mover 30b is mechanically connected to the mounting tool 20 via the sliding shaft 32. In addition, the sliding shaft 32 is mounted to the moving body 46 via the leaf spring 34, which is capable of deforming in the Z-axis direction. Furthermore, the guide member 36 is fixed to the moving body 46. The sliding shaft 32 is inserted into the through hole formed in the guide member 36 and can slide along the through hole.

[0064] When a current is applied to the VCM 30, the mover 30b moves relative to the moving body 46 in the Z-axis direction. At this time, the sliding shaft 32 and the mounting tool 20 fixed to the sliding shaft 32 move together with the mover 30b in the Z-axis direction, while the leaf spring 34 is elastically deformed. A linear encoder 50 is provided in the first unit 24a to detect the movement of the sliding shaft 32. The linear encoder 50 has a movable part 50a located near the upper end of the sliding shaft 32 and a fixed part 50b whose position is fixed. The linear encoder 50 outputs the relative displacement between the two. The linear encoder 50 can be a magnetic encoder that magnetically detects displacement or an optical encoder that optically detects displacement. In the case of an optical encoder, the fixed part 50b includes a scale with multiple slits formed in the displacement direction, and the movable part 50a includes a light source and a light receiving element disposed on both sides of the scale. In the case of a magnetic encoder, the fixed part 50b includes a magnetic scale, and the movable part 50a includes a magnetic sensor. The detection value obtained by the linear encoder 50 is output to the controller 16.

[0065] The second unit 24b causes the first unit 24a to move up and down relative to the base member 38 in the Z-axis direction. The second unit 24b has a lifting motor 40 as a drive source. A lead screw 42 extending axially is connected to the lifting motor 40 via a coupling; the lead screw 42 rotates as the lifting motor 40 drives it. A movable block 44 is screwed onto the lead screw 42, and the movable block 44 is fixed to the upper surface of the stator 30a of the VCM 30. Additionally, a movable body 46 is fixed to the side of the stator 30a. The movable body 46 can slide along a guide rail 48 fixed to the base member 38. When current is applied to the lifting motor 40, the lead screw 42 rotates, and the movable block 44 moves up and down in the Z-axis direction. Furthermore, the first unit 24a and the mounting tool 20 fixed to the movable block 44 also move up and down as the movable block 44 moves. The lifting amount of the first unit 24a generated by the second unit 24b is also detected by a sensor (such as an encoder mounted on the lifting motor 40) and sent to the controller 16.

[0066] The controller 16 controls the operation of the tool heater 26, the lifting mechanism, the platform 12, and the XY platform 18. The controller 16 is a computer physically comprising a processor 16a and a memory 16b. This "computer" also includes a microcontroller that integrates a computer system into an integrated circuit. Furthermore, the term "processor 16a" refers to a processor in a broad sense, including general-purpose processors (e.g., central processing units (CPUs)) or dedicated processors (e.g., graphics processing units (GPUs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), programmable logic devices, etc.). Additionally, the operation of the processor 16a, as described below, can be performed not only by a single processor but also collaboratively by multiple processors located in physically separate locations. Similarly, the memory 16b does not need to be a single physical component and can be composed of multiple memories located in physically separate locations. Additionally, the memory 16b may also include at least one of a semiconductor memory (e.g., random access memory (RAM), read-only memory (ROM), solid-state drive, etc.) and a magnetic disk (e.g., hard disk drive, etc.).

[0067] Next, a method for bonding a semiconductor chip 100 using this manufacturing apparatus 10 will be described. Figure 2 This is a schematic diagram showing the bonding configuration of the semiconductor chip 100. (Example) Figure 2 As shown in the left figure, a plurality of electrodes 112 are formed on the upper surface of the substrate 110. Additionally, the semiconductor chip 100 has a plurality of bumps 104 protruding from the bottom surface of the chip body 102 and containing conductive metal such as solder. When mounting the semiconductor chip 100, the semiconductor chip 100 is heated while the bumps 104 are in contact with the electrodes 112 of the substrate 110, thereby achieving the desired effect. Figure 2 The bump 104 is fused to the electrode 112 as shown in the right figure. Furthermore, in Figure 2 Although not shown in the figure, a thermosetting resin layer, such as a non-conductive film layer, may be further provided on the bottom surface of the chip body 102.

[0068] Here, to maintain the quality of the semiconductor device, it is necessary to prevent excessive flattening of the bumps 104 and maintain the gap G between the bottom surface of the bonded chip body 102 and the upper surface of the substrate 110 at a target value. If, during the bonding process, the molten bumps 104 are excessively flattened and expand laterally, short circuits may occur between them and adjacent bumps 104. Furthermore, if the gap G deviates, the quality of the semiconductor device cannot be properly maintained. Therefore, during bonding, the axial position of the semiconductor chip 100 needs to be correctly managed, and consequently, the axial position of the bottom surface of the mounting tool 20 needs to be correctly managed. However, when managing the axial position of the mounting tool 20, thermal expansion and deformation become problems. For this, refer to... Figure 3 , Figure 4 Please provide an explanation.

[0069] As described above, when bonding the semiconductor chip 100, the semiconductor chip 100 is heated using a tool heater 26 provided on the mounting tool 20. The heat generated during the heating causes thermal expansion and contraction of components surrounding the tool heater 26, specifically the mounting tool 20 or the sliding shaft 32 (hereinafter referred to as "peripheral components"). Figure 3 The double-dotted line represents the shape of the peripheral components after thermal expansion and contraction. If the peripheral components thermally expand, the axial position of the movable part 50a of the linear encoder 50 will change even if the axial position of the bottom surface of the mounting tool 20 does not change. Therefore, in the event of thermal expansion and contraction, it is impossible to accurately determine the actual position of the semiconductor chip 100 based on the detection position Pd obtained by the linear encoder 50, etc., and thus it is impossible to accurately manage the gap amount G.

[0070] Additionally, during the bonding of the semiconductor chip 100, the mounting tool 20 applies a predetermined standard load Fs to the semiconductor chip 100, pressing the semiconductor chip 100 against the substrate 110. At this time, a predetermined reaction force is applied from the semiconductor chip 100 towards the mounting tool 20. The sliding shaft 32 is subjected to this reaction force and sometimes... Figure 4 As shown by the double-dotted line, deformation occurs. If the sliding shaft 32 deforms, the axial position of the movable part 50a of the linear encoder 50 will naturally change accordingly. Moreover, in this case, it is impossible to accurately determine the actual position of the semiconductor chip 100 based on the detection position Pd obtained by the linear encoder 50, etc., and thus it is impossible to accurately manage the gap amount G.

[0071] Furthermore, when the bump 104 is continuously heated and pressurized while the sliding shaft 32 is deformed, the reaction force from the semiconductor chip 100 decreases sharply at the point when the bump 104 melts. Moreover, in this situation, the deformation of the sliding shaft 32 is instantly eliminated, and the bottom surface of the mounting tool 20 drops rapidly. In this case, the molten bump 104 is pressed by the mounting tool 20, and the bump 104 may be excessively flattened.

[0072] In this example, to avoid this problem, the lifting mechanism is driven in the upward direction before the protrusion 104 melts, eliminating the deformation of the sliding shaft 32. Furthermore, the position of the installation tool 20 is controlled by offsetting the thermal expansion and contraction of the surrounding components, thereby maintaining the clearance G at a predetermined target value. Hereinafter, refer to... Figure 5 , Figure 6 The detailed sequence of this connection is explained. Figure 5 This is a flowchart representing the process of joining. Figure 6 It is a graph showing the time changes of various parameters in the bonding process. Figure 6 (a) is a graph showing the axial position (hereinafter referred to as "detection position Pd") of the installation tool 20, which is determined based on the detection value of the position sensor (linear encoder 50, etc.) installed on the lifting mechanism. Figure 6 (b) is a graph showing the actual distance (hereinafter referred to as "distance Dr") from the upper surface of the stage 12 to the bottom surface of the mounting tool 20 when the mounting tool 20 holds the semiconductor chip 100. Figure 6 (c) is a graph showing the change in the pressing load Fp applied to the semiconductor chip 100 by the lifting mechanism. Figure 6 (d) is a diagram showing the driving state of the tool heater 26. Furthermore, regarding the distance Dr, the reference position of the distance changes due to the deformation or thermal expansion of the stage 12.

[0073] When bonding the semiconductor chip 100 to the substrate 110, the controller 16 drives the lifting mechanism to lower the semiconductor chip 100, causing it to land on the substrate 110 (S10, S12). Specifically, the controller 16 first drives the lifting motor 40, causing the mounting tool 20 to descend at high speed to the vicinity of the substrate 110. Then, with the lifting motor 40 stopped, the VCM 30 is driven to lower the mounting tool 20 at low speed. At this time, the change in the detection position Pd is monitored. If the detection position Pd does not change, it is determined that the chip has landed. Furthermore, as mentioned above, due to some deformation of the sliding shaft 32, etc., there is some error between the actual landing time and the landing time detected by the controller 16.

[0074] exist Figure 6In the example, at time t1, the semiconductor chip 100 actually lands on the substrate 110, and the distance Dr remains unchanged after time t1. However, after the semiconductor chip 100 actually lands, the detection position Pd changes due to deformation of the sliding shaft 32, etc. Therefore, the controller 16 determines that the chip has landed at time t2, when the sliding shaft 32, etc., has sufficiently deformed and the detection position Pd remains unchanged.

[0075] If landing is detected (Yes in S12), the controller 16 performs a first process (S14-S18) to pressurize and heat the semiconductor chip 100 with a certain load. Specifically, the controller 16 begins load control of the lifting mechanism (S14) by applying a pre-defined standard load Fs to the semiconductor chip 100. That is, since the VCM 30 outputs torque proportional to the applied current, the controller 16 continuously applies a certain current corresponding to the standard load Fs to the VCM 30. Figure 6 During the period from time t2 to time t4, a standard load Fs is applied to the semiconductor chip 100.

[0076] If a standard load Fs is applied, then the controller 16 switches on the tool heater 26, initiating heating of the semiconductor chip 100 (S16). Figure 6 In the example, at time t4, the tool heater 26 is turned on. As a result, the temperature of the semiconductor chip 100 begins to rise.

[0077] The controller 16 monitors whether the elapsed time since the start of heating has reached the standby time Ta (S18). Here, the standby time Ta is the time obtained by subtracting a certain margin α from the time from the start of heating until the bump 104 melts (hereinafter referred to as "melting time Tm"). That is, Ta = Tm - α. From another perspective, the point in time when the standby time Ta has elapsed can be considered as just before the bump 104 is about to melt. The standby time Ta and the melting time Tm can be obtained in advance through experiments, which will be described later. If the standby time Ta has elapsed since the start of heating (as in S18), the controller 16 determines that the bump 104 is just before melting. Figure 6 In the example, time t4 is the point in time before the standby time Ta has elapsed and the bump 104 is about to melt.

[0078] If melting is imminent, the controller 16 performs a deformation relief process (S20) to eliminate deformation of the joint 14. Specifically, the controller 16 raises the VCM 30 by a predetermined deformation relief amount Aa in the direction that raises the mounting tool 20 (S20). Here, the deformation relief amount Aa is the amount of movement of the VCM 30 required to eliminate deformation generated by the lifting mechanism when the semiconductor chip 100 is pressurized with a standard load Fs. The deformation relief amount Aa, like the standby time Ta and melting time Tm, can be obtained experimentally beforehand, as will be described later. In summary, by driving the VCM 30 in the rising direction by the deformation relief amount Aa, deformation of the joint 14, and especially the sliding shaft 32, is eliminated. Figure 6 In the example, during the period from time t4 to time t5, VCM 30 is driven until the deformation elimination amount Aa at the detection position Pd increases. At this time, the distance Dr of the mounting tool 20 does not change, the deformation of the sliding shaft 32 is eliminated, and the pressing load Fp decreases sharply.

[0079] If the deformation can be eliminated, the controller 16 performs a second process (S22-S26) to maintain the gap amount G at the target value. Specifically, the controller 16 starts position control of the VCM 30 according to a pre-generated target distribution (S22). The target distribution is a movement distribution that defines the target movement position of the lifting mechanism. The controller 16 performs position feedback control of the VCM 30 in such a way that the difference between the command position obtained according to the target distribution and the detection position Pd is close to zero. Here, as described above, the detection position Pd is affected by the thermal expansion and contraction of the mounting tool 20 and the platform 12, resulting in a deviation between the distance Dr of the upper surface of the platform 12 and the bottom surface of the mounting tool 20. That is, the controller 16 detects the position where the distance Dr of the platform 12 is different from the height D1 of the platform 12 after the deformation is eliminated due to the thermal expansion of the platform 12 and the mounting tool 20 as the detection position Pd. The target distribution is set in such a way that the error caused by the thermal expansion and contraction is offset and the actual gap amount G is maintained at the target value.

[0080] Specifically, refer to Figure 6 This will be explained. With the height D1 after deformation elimination as a reference and the distance Dr of the mounting tool 20 kept constant, the detection position Pd is affected by the thermal expansion and contraction of the mounting tool 20. Therefore, as... Figure 6The position changes as shown by the double-dotted line in (a). That is, the detection position Pd, which is maintained at Dr = D1, gradually rises above the moment t3 when the tool heater 26 is turned on, and gradually falls after the moment t8 when the tool heater 26 is turned off. On the other hand, in order to set the gap amount G as the target value, the distance Dr needs to be further reduced from the height D1 by the target flattening amount Gd. To achieve this movement of the distance Dr, the position of the lifting mechanism can be controlled by subtracting the target flattening amount Gd from the position indicated by the double-dotted line.

[0081] The target distribution used in step S22 represents the distribution of positions after subtracting the target flattening amount Gd from the position indicated by the double-dotted line. According to this target distribution, by controlling the position of the VCM 30, the distance Dr can be kept constant, and the gap amount G can be kept at the target value. Furthermore, this target distribution is generated before joining, which will be described later.

[0082] The controller 16 disconnects the tool heater 26 according to a pre-set temperature distribution (S24). As a result, the temperature of the once-molten bump 104 drops sharply and hardens. Figure 6 In the example, at time t8, the tool heater 26 is disconnected. As a result, the bump 104 hardens. Furthermore, by disconnecting the tool heater 26, the temperature of the lifting mechanism (especially the sliding shaft 32) also decreases, eliminating thermal expansion and contraction of the lifting mechanism. After the temperature decreases, or simultaneously, the installation tool 20 is lowered according to the target distribution.

[0083] Then, if a predetermined hardening time Tb (yes in S26) has elapsed since the tool heater 26 was disconnected, the controller 16 determines that the bump 104 has hardened. Furthermore, the hardening time Tb can be predetermined based on prior experiments or past experience. If the hardening time Tb has elapsed, the controller 16 releases the mounting tool 20 from holding the semiconductor chip 100, and then raises the mounting tool 20 (S28). Thus, the bonding process for one semiconductor chip 100 is completed. The same process is then repeated for other semiconductor chips 100.

[0084] As is clear from the above description, in this example, deformation of the joint head 14 is eliminated by driving the VCM 30 in the upward direction just before the bump 104 is about to melt. As a result, when the bump 104 melts, it is effectively prevented that the installation tool 20 moves too downward and excessively flattens the bump 104.

[0085] Furthermore, in this example, the melting time of bump 104 (i.e., melting time Tm) is predetermined, and before bump 104 melts, the self-load control is switched to position control. This structure prevents excessive flattening of bump 104. That is, most existing technologies perform load control by applying a certain load to the semiconductor chip 100. If the detection position Pd drops by a certain amount, it is determined that bump 104 has melted. In this technology, at the point when bump 104 melts, the mounting tool 20 drops significantly, and the gap amount G becomes less than the target value. For example, in Patent Document 1, at the point when bump 104 melts, the gap amount G becomes less than the target value. Therefore, in Patent Document 1, after the gap amount G becomes less than the target value, the mounting tool is raised to correct the gap amount G to the target value. However, if bump 104 is flattened significantly as in Patent Document 1, the laterally extended bump 104 may come into contact with adjacent bumps 104, potentially causing a short circuit. On the other hand, as in this example, by switching to position control just before the bump 104 is about to melt, the bump 104 is not excessively flattened, which effectively prevents short circuits.

[0086] Next, the deformation relief amount Aa, standby time Ta, and the acquisition of the target distribution used in this bonding process will be explained. Before starting the manufacturing of the semiconductor device, the manufacturing apparatus 10 performs deformation relief amount detection processing, melting time point detection processing, and target distribution generation processing. These processes will be explained below.

[0087] First, refer to Figure 7 , Figure 8 The deformation relief detection process will be explained. As described above, during the joining process, just before the protrusion 104 is about to melt, the VCM 30 is driven in the upward direction with a deformation relief amount Aa, thereby eliminating the deformation of the joint head 14 (especially the mounting tool 20 and the sliding shaft 32). The deformation relief amount Aa used at this time is detected by a deformation relief detection process performed before the joining process. Figure 7 This is a flowchart illustrating the process of detecting and processing the amount of deformation elimination. Figure 8 This is a graph showing the changes in the detection position Pd and the detection load Fd during the deformation elimination detection process.

[0088] During the deformation reduction detection process, the mounting tool 20 is used without holding the semiconductor chip 100. Furthermore, a load sensor (e.g., a load cell) is pre-positioned on the bottom surface of the mounting tool 20 or the upper surface of the substrate 110 so that the pressing load of the mounting tool 20 on the substrate 110 can be detected as the detection load Fd. Furthermore, the mounting tool 20 and the substrate 110 are set to the same pre-defined temperature. If this pre-preparation is complete, the controller 16 drives the lifting mechanism to lower the mounting tool 20 (without holding the semiconductor chip 100) until it lands on the substrate 110 (S30, S32). Figure 8 In this example, the moment t2 when the change in the detection position Pd stops is considered as the landing point. Furthermore, at this time, the current applied to the VCM 30 is adjusted according to the mounting tool 20 pressing the substrate 110 with a standard load Fs. Furthermore, the pre-defined temperature is, for example, room temperature (20°C), or it can be set to 50°C or 100°C by heating the mounting tool and stage with a heater. In this example, the deformation relief amount Aa detected by the deformation relief amount detection process is set as the increase in VCM 30 during the deformation relief process. However, the increase in VCM 30 during the deformation relief process can also be a value after some correction to the deformation relief amount Aa.

[0089] If the mounting tool 20 lands on the substrate 110, the controller 16 stores the detection position Pd at the specified time point as P[0] in its memory (S34). Figure 8 In the example, the detection position Pd at time t2 is stored as P[0]. Then, the controller 16 initializes the parameter i, setting it to i = 1 (S35). Afterwards, the controller 16 drives the VCM 30 in the upward direction at a predetermined unit interval (S36). That is, the VCM 30 is driven until the detection position Pd detected by the linear encoder 50 changes by a unit interval. The value of the unit interval is not particularly limited and can be set to a value sufficiently small compared to the detection error caused by the deformation of the sliding shaft 32. Figure 8 In the example, at time t3, the first unit spacing amount of upward drive is completed. By driving VCM 30 in the upward direction, the pressing load is slightly reduced, and correspondingly, the deformation of sliding shaft 32, etc., is also slightly eliminated.

[0090] If the upward drive of the unit spacing is completed, the controller 16 stores the detection load Fd and detection position Pd at the specified time point as F[i] and P[i] in the memory, respectively (S38). Then, the controller 16 compares the current detection load F[i] with the detection load F[iN] from N times ago (S40). Furthermore, N is an integer greater than or equal to 1. If the comparison result is that F[i] ≒ F[iN] is not true (No in S40), it can be determined that the detection load Fd has changed due to the increase in the unit spacing. In this case, the controller 16 proceeds to step S42, increments the parameter i, and then executes steps S38 and S40 again. Additionally, although not shown in the flowchart, if i < N and there is no detection load F[iN] from N times ago, the process also proceeds to step S42.

[0091] On the other hand, when F[i]≒F[iN] holds (which is true in S40), that is, when the VCM 30 is driven in the upward direction and the detected load Fd does not change, P[iN]-P[0] is stored in the memory as the deformation elimination amount Aa (S44). P[iN]-P[0] is the amount of movement of the lifting mechanism from the start of driving the VCM 30 in the upward direction until the change of the detected load Fd stops.

[0092] As N=3, if referring to Figure 8 To illustrate with an example, at time t8, since F[i] is Fa and F[i-3] is Fb, F[i] ≠ F[iN]. Therefore, in this case, controller 16 does not proceed to step S44, but proceeds to step S42. Then, if it becomes time t9, then F[i] = Fa and F[i-3] = Fa, therefore F[i] ≒ F[iN] holds. In this case, controller 16 proceeds to step S44. Here, at time t9, P[i-3] is the detection position Pd at time t6, and P[0] is the detection position Pd at time t2. Therefore, in this case, the deformation elimination amount Aa becomes as follows: Figure 8 As shown. Thus, by obtaining the deformation relief amount Aa through experiments beforehand, the deformation of the lifting mechanism can be eliminated more reliably during the joining process.

[0093] Next, refer to Figure 9 , Figure 10 The melting time detection process will be explained. As described above, in the joining process, a deformation elimination process is performed just before the bump 104 is about to melt. In order to perform the deformation elimination process at the stated time, it is necessary to know in advance the melting time of the bump 104. Therefore, in this example, a melting time detection process is performed before the joining process. Figure 9 This is a flowchart illustrating the process of detecting and processing the melting time point. Figure 10 It is a graph representing the detection position Pd, pressing load, and driving state of tool heater 26 in the melting time point detection process.

[0094] During the melting time detection process, the semiconductor chip 100 is held in place by the mounting tool 20 beforehand. Then, the controller 16 drives the lifting mechanism to lower the mounting tool 20 until the semiconductor chip 100 lands on the substrate 110 (S50, S52). If the semiconductor chip 100 lands on the substrate 110 (yes in S52), the controller 16 begins load control of the lifting mechanism by applying a pre-defined standard load Fs to the semiconductor chip 100 (S54), and turns on the tool heater 26 (S56). Figure 10 In the example, landing is detected at time t1, and a certain load is then applied to the semiconductor chip 100. Subsequently, at time t2, the tool heater 26 is turned on.

[0095] If the tool heater 26 is turned on, the controller 16 monitors the change in the detection position Pd detected by the linear encoder 50. If the detection position Pd decreases by a predetermined reference displacement Δs or more, it determines that the bump 104 has melted. Specifically, the controller 16 initializes the parameter i to i = 0 (S58). Then, it stores the current detection position Pd as P[i] in the memory (S60). Then, the controller 16 compares the difference between the current detection position P[i] and the previous detection position P[i-1] with the predetermined reference displacement Δs (S62). If the comparison result is P[i] - P[i-1] < Δs (not in S62), the controller 16 proceeds to step S64, increments the parameter i, and then performs steps S60 and S62 again. In addition, although not shown in the flowchart, if i = 0 and P[i-1] does not exist, it does not proceed to step S66, but proceeds to step S64 instead.

[0096] On the other hand, if P[i]-P[i-1]≧Δs (which is true in S62), it can be determined that the bump 104 has melted. In this case, the controller 16 stores the elapsed time since the tool heater 26 was turned on as the melting time Tm in its memory (S66). Figure 10 In the example, at time t3, the detection position Pd drops sharply, therefore, at time t3, it can be determined that the bump 104 has melted. Furthermore, in this case, the time from time t2 to time t3 is stored in the memory as the melting time Tm. If the melting time Tm is available, the controller 16 disconnects the tool heater 26, causing the mounting tool 20 to rise (S68). Thus, the melting time detection process ends.

[0097] During the joining process, the standby time Ta is obtained by subtracting a certain margin α from the melting time Tm. Thus, by experimentally detecting the melting point of the bump 104 before the joining process, deformation elimination can be performed just before the bump 104 melts. As a result, the situation where the mounting tool 20 drops sharply and instantaneously when the bump 104 melts can be prevented. Furthermore, excessive flattening of the bump 104 can be prevented.

[0098] Next, refer to Figure 11 , Figure 12 The target distribution generation process will be explained. As described above, in the joining process, after the protrusion 104 melts, the position of the lifting mechanism is controlled by offsetting the thermal expansion and contraction of the joining head 14, thereby maintaining the gap amount G at a predetermined target value. In the target distribution generation process, the target distribution used in the position control is generated. Figure 11 This is a flowchart illustrating the process of generating the target distribution. Figure 12 This is a graph representing the changes in various parameters during the target distribution generation process. More specifically, Figure 12 (a) is a graph representing the reference distribution 90 obtained in the target distribution generation process. Figure 12 (b) is a graph representing the driving state of the tool heater 26 in the target distribution generation process. Figure 12 (c) is a graph representing the reference distribution 90*, ideal distribution 92, and target distribution 94 after offset processing.

[0099] During the target distribution generation process, the mounting tool 20 is set to a state where the semiconductor chip 100 is not held. Then, the controller 16 drives the lifting mechanism to lower the mounting tool 20, which is not holding the semiconductor chip 100, until it lands on the substrate 110 (S70, S72). If the mounting tool 20 lands on the substrate 110, the controller 16 begins control of the tool heater 26 (S76). The control of the tool heater 26 is performed according to the temperature distribution, similar to the bonding process. That is, the time points for turning on or off the tool heater 26 during the bonding process are predetermined, and these time points are stored as a temperature distribution in the memory of the controller 16. In step S76, control of the tool heater 26 according to the temperature distribution begins. In addition, the controller 16 initializes the parameter i, setting i = 0 (S78). If the control of the tool heater 26 is started, the controller 16 repeats the process of storing the current detection position Pd as P[i] in the memory at a specified sampling interval (S80) and the process of incrementing the parameter i (S84) until the end time of the engagement process is reached (until it is in S82).

[0100] exist Figure 12In the example, at time t1, control of the tool heater 26 begins, and at time t1, the tool heater 26 is turned on. The detection position Pd at time t1 (refer to...) Figure 12 The graph (a) is stored in memory as the initial position P[0]. The temperature of the mounting tool 20 and sliding shaft 32 gradually increases due to the temperature distribution and the activation of the tool heater 26, causing thermal expansion. As a result, although the position of the bottom surface of the mounting tool 20 does not change, the detection position Pd detected by the linear encoder 50 gradually increases. Furthermore, in Figure 12 In the example, at time t3, the thermal expansion of the sliding shaft 32, etc., converges, and the detection position Pd also becomes constant. Subsequently, at time t4, if the tool heater 26 is disconnected to begin cooling, the temperature of the sliding shaft 32, etc., decreases, and the thermal expansion is eliminated. Therefore, after time t4, the detection position Pd gradually decreases. Moreover, after time t5, when the temperature of the sliding shaft 32, etc., returns to a predetermined temperature, the detection position Pd remains constant. Furthermore, at time t6, which is the end time point, the acquisition of the detection position Pd ends. In steps S80 to S84, the aforementioned... Figure 12 The data shown in (a) serves as a reference distribution 90. The melting time Tm - excess α is subtracted from the reference distribution 90. Figure 12 The value obtained by taking the position P[i] at time ta) is the thermal expansion of the joint 14.

[0101] If a reference distribution 90 is obtained, the controller 16 generates a target distribution 94 based on a pre-stored ideal distribution 92 and the reference distribution 90 (S86). The ideal distribution 92 is the movement distribution of the joint 14 in an ideal state where no thermal expansion or deformation occurs.

[0102] exist Figure 12 In (c), the solid line represents the target distribution 94, the double-dotted line represents the ideal distribution 92, and the single-dotted line represents the reference distribution 90* after offsetting, which makes the position at time ta consistent with the ideal distribution 92. Figure 12 As shown, in the ideal distribution 92, at the moment t2 when the bump 104 melts, the target flattening amount Gd decreases, and thereafter, the same height position is maintained. Then, after the moment t6 when the bump 104 hardens, it rises.

[0103] The target distribution 94 can be obtained by adding the thermal expansion of the joint 14, calculated based on the reference distribution 90, to the ideal distribution 92. As described above, the thermal expansion is obtained by subtracting the value of position P[i] at the melting time Tm - margin α (time ta) from the reference distribution 90. By adding the thermal expansion to the ideal distribution 92, the target distribution 14 can be obtained. Figure 12The target distribution 94 is shown as a solid line in the graph of (c). During the actual joining process, the lifting mechanism is positioned according to the target distribution 94. Moreover, by using the target distribution 94, even if the joint head 14 expands thermally, the bottom position of the installation tool 20, and thus the gap amount G, can be kept constant.

[0104] As explained above, in this example, the deformation relief amount Aa, the melting time, and the target distribution are obtained in advance. Then, during the actual bonding process, before the bump 104 melts, the lifting mechanism is driven in the upward direction by the deformation relief amount Aa to eliminate the deformation of the bonding head 14, and then the lifting mechanism is driven according to the target distribution that offsets thermal expansion. By adopting the above structure, the excessive flattening of the molten bump 104 can be effectively prevented, and the quality of the semiconductor device can be well maintained. Furthermore, the structure described so far is one example. Other structures can be appropriately modified as long as the lifting mechanism is driven in the upward direction to eliminate the deformation of the bonding head 14 before the bump 104 melts, and then the lifting mechanism is driven in a manner that offsets thermal expansion. For example, in the above description, the movement amount of the lifting mechanism in the deformation relief process, i.e., the deformation relief amount Aa, is obtained through prior experiments (deformation relief amount detection process), but the deformation relief amount Aa can also be obtained by other methods. For example, the deformation relief amount Aa can be obtained by simulating the rigidity of the joint 14 or the standard load Fs applied to the semiconductor chip 100 in the first process.

[0105] Furthermore, the execution time of the deformation elimination process is only required to be before the melting of the protrusion 104, and does not necessarily have to be just before it is about to melt. Also, in the above description, the melting time point detection process determines the melting of the protrusion 104 based on the change in the detection position Pd, but it can also be determined based on other parameters, such as changes in the pressing load. Furthermore, the lifting mechanism in this example has a first unit 24a driven by the VCM 30 and a second unit 24b driven by the lifting motor 40, but the structure of the lifting mechanism can be appropriately modified as long as it can perform both load control and position control.

Claims

1. A semiconductor device manufacturing apparatus, characterized in that... include: Stage, supporting the substrate; The connector includes a mounting tool for holding a chip with bumps on its bottom surface, a tool heater mounted on the mounting tool for heating the chip, and a lifting mechanism for moving the mounting tool in the vertical direction. as well as The controller drives the bonding head and performs the bonding process to bond the chip to the substrate. The controller operates during the engagement process: In the first process, after the chip is placed onto the substrate, the tool heater and the lifting mechanism are driven to start heating the chip, while simultaneously applying pressure to the chip onto the substrate. Deformation elimination process: After the first process and before the melting of the protrusion, the deformation of the joint is eliminated by driving the lifting mechanism in the upward direction; as well as In the second process, after the deformation elimination process, the lifting mechanism is positioned to offset the thermal expansion of the joint, thereby maintaining the gap between the bottom surface of the chip and the upper surface of the substrate at a predetermined target value. In the deformation elimination process, the lifting mechanism is driven in the upward direction based on the deformation elimination amount, wherein the deformation elimination amount is the amount of movement required to eliminate the deformation generated by the lifting mechanism when the chip is pressurized with a standard load.

2. The semiconductor device manufacturing apparatus according to claim 1, characterized in that... The controller performs deformation elimination detection processing before the joining process. In the deformation elimination detection process, while the mounting tool and the platform are kept at a predetermined temperature, the lifting mechanism is driven to press the substrate with the mounting tool. Then, while driving the lifting mechanism in the upward direction, the pressing load of the mounting tool on the substrate is detected, and the amount of movement of the lifting mechanism from the start of driving in the upward direction until the change of the pressing load stops is stored as the deformation elimination amount.

3. The semiconductor device manufacturing apparatus according to claim 1 or 2, characterized in that... Before bonding the chip to the substrate, the controller performs a process to detect the melting time of the bumps. In the melting time detection process, after the chip is placed onto the substrate, the chip is heated according to a predetermined temperature distribution, and the time from the start of heating until the bump melts is stored as the melting time. The controller determines the execution time of the deformation elimination process based on the melting time.

4. The semiconductor device manufacturing apparatus according to claim 1 or 2, characterized in that... The lifting mechanism includes: a sliding shaft mechanically connected to the installation tool; and a drive source for raising and lowering the sliding shaft. And a position sensor, which uses the axial position of the sliding shaft as the detection position. The controller performs a target distribution generation process before the joining process. In the target distribution generation process, after the lifting mechanism is driven to allow the mounting tool to land on the substrate or platform, the mounting tool is heated according to a predetermined temperature distribution. Based on the change in detection position obtained by the position sensor at this time, the thermal expansion of the joint is obtained, and a movement distribution that cancels out the thermal expansion is generated as the target distribution. In the second process, the lifting mechanism is position-controlled according to the target distribution.

5. A method for manufacturing a semiconductor device, comprising driving a joint head having a mounting tool, a tool heater mounted on the mounting tool, and a lifting mechanism for moving the mounting tool in a vertical direction, thereby bonding a chip held in the mounting tool to a substrate supported on a stage, the method for manufacturing the semiconductor device being characterized by comprising: In the first step, after the mounting tool is lowered to allow the chip to land on the substrate, the tool heater and the lifting mechanism are driven to start heating the chip and simultaneously apply pressure to the chip on the substrate. The deformation elimination step, which occurs after the first step and before the melting of the bumps located on the bottom surface of the chip, eliminates the deformation of the joint by driving the lifting mechanism in the upward direction; as well as In the second step, after the deformation elimination step, the lifting mechanism is positioned to offset the thermal expansion of the joint, thereby maintaining the gap between the bottom surface of the chip and the upper surface of the substrate at a predetermined target value. In the deformation elimination step, the lifting mechanism is driven in the upward direction based on the deformation elimination amount, wherein the deformation elimination amount is the amount of movement required to eliminate the deformation generated by the lifting mechanism when the chip is pressurized with a standard load.

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