WO2022264427A1

WO2022264427A1 - Semiconductor device manufacturing apparatus and manufacturing method

Info

Publication number: WO2022264427A1
Application number: PCT/JP2021/023268
Authority: WO
Inventors: 広幸笠間
Original assignee: 株式会社新川
Priority date: 2021-06-18
Filing date: 2021-06-18
Publication date: 2022-12-22
Also published as: JPWO2022264427A1; CN116686072A; KR20230130123A

Abstract

This semiconductor device manufacturing apparatus comprises: a capillary (30); a clamper (34); a shifting mechanism (18) having one or more driving motors (22); a position sensor (28) that detects the position of the capillary (30); and a controller (50) that controls the driving of the capillary (30), the clamper (34) and the shifting mechanism (18). The controller (50) is configured to execute: a tail cut processing that cuts a tail by shifting the capillary (30) in such a direction that the capillary (30) moves away from a surface of interest with the clamper (34) closed; and an index measurement processing that measures a rupture index Sb that is the peak value of a positional deviation of the capillary (30) immediately after the cutting of the wire W or that is the current values of the driving motors (22) at the time of cutting the wire W.

Description

Semiconductor device manufacturing apparatus and manufacturing method

This specification discloses a semiconductor device manufacturing apparatus and manufacturing method comprising a capillary through which a wire is inserted and a clamper that grips the wire.

A manufacturing apparatus that manufactures semiconductor devices by connecting electrodes of a semiconductor chip and electrodes of a substrate with conductive wires has been widely known. For example, Patent Document 1 discloses a semiconductor device manufacturing apparatus (referred to as "bonding device") is disclosed.

In such manufacturing equipment, a wire connects the first bond point and the second bond point. Further, in the manufacturing apparatus, when the second bond for bonding the wire to the second bond point is completed, the capillary is moved with the clamper open to form a tail, and then the capillary is moved with the clamper closed. perform a tail cut to cut the wire.

JP 2012-256861 A

Here, if the operating conditions of the manufacturing equipment when performing the 2nd bond and the tail cut are not appropriate, NSOL where the wire is not sufficiently bonded at the 2nd bond point, Notail where the tail of sufficient length is not formed, and capillary Defects such as S-shaped bending, in which the inserted wire bends in an S-shape, occur. However, conventionally, there has been no index for quantitatively evaluating the adequacy of operating conditions. As a result, conventionally, the operator had no choice but to correct the operating conditions based on his/her experience while looking at the results of the quality inspection of actually manufactured semiconductor devices, and it took a long time to narrow down the operating conditions. In addition, conventionally, in order to confirm the presence or absence of defects, it is necessary to inspect actually manufactured semiconductor devices, and it has been difficult to determine the presence or absence of defects during the manufacturing process.

Therefore, this specification discloses a semiconductor device manufacturing apparatus that provides an evaluation index for quantitatively evaluating the adequacy of the operating conditions of the manufacturing apparatus.

The apparatus for manufacturing a semiconductor device disclosed in this specification includes a capillary, through which a wire is inserted, which presses and bonds the wire extending from the tip thereof to a target surface, and which moves in conjunction with the capillary to grip the wire. a moving mechanism having one or more drive motors to move the capillary by the power of the drive motor; a position sensor for detecting the position of the capillary as a detection position; the capillary, the clamper, and a controller for controlling driving of the movement mechanism, wherein the controller moves the capillary in the away direction with the clamper closed after joining the wire to the target surface and forming the tail. a tail cut process for cutting the tail by moving it; a peak value of a deviation between a command position for movement of the capillary immediately after cutting the wire and the detected position; and an index measurement process of measuring the current value as a fracture index.

In this case, in the index measurement process, the controller may also measure a breaking distance, which is a moving distance of the capillary from when the clamper is closed until the wire is cut.

Further, a UI device is provided for receiving an operation input from an operator and outputting information to the operator, and the controller performs the tail cutting process two or more times when the operator instructs measurement of the fracture index. The measurement values of the fracture index obtained by each of the tail cutting processes performed two or more times may be presented to the operator via the UI device.

In this case, the controller may present, in a graph format, a list of measured values of the rupture index obtained in each of the two or more tail cutting processes.

Further, the controller may output an alarm when the fracture index is out of a predetermined reference range.

In the method for manufacturing a semiconductor device disclosed in this specification, after a wire extending from the tip of a capillary is pressed against a target surface to be bonded, a clamper is closed to hold the wire, and then the capillary is moved to the target surface. a peak value of the deviation between the command position for movement of the capillary immediately after cutting the wire and the detected position, or the wire and an index measuring step of measuring the current value of the drive motor at the time of cutting as a fracture index.

According to the technology disclosed in this specification, the breaking strength is provided quantitatively, so the operator can easily evaluate whether the operating conditions are appropriate.

It is a figure which shows the structure of a manufacturing apparatus. It is an image figure which shows the flow of wire bonding. It is an image figure which shows the flow of wire bonding. It is an image figure which shows the flow of wire bonding. It is an image figure which shows the flow of wire bonding. It is an image figure which shows the flow of wire bonding. It is an image figure which shows the flow of wire bonding. FIG. 10 is a diagram showing an example of temporal changes in positional deviation obtained during tail cut processing; It is a figure which shows an example of a measurement mode screen. FIG. 10 is a diagram showing an example of a graph screen of fracture indices presented to an operator; It is a figure which shows an example of the graph screen of the breaking distance shown to an operator. 4 is a flow chart showing the flow of processing by the controller during mass production of products;

The semiconductor device manufacturing apparatus 10 will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of a manufacturing apparatus 10. As shown in FIG. This manufacturing apparatus 10 is a wire bonding apparatus that connects a first bonding point B1 and a second bonding point B2 with a wire W. Generally, the first bonding point B1 is set on a pad of a semiconductor chip 110. The second bonding point B2 is set on the lead of the substrate 100, which is the lead frame on which the semiconductor chip 110 is mounted.

The manufacturing apparatus 10 includes a bonding head 12, a moving mechanism 18, a stage 14, a rotating spool 42, a torch electrode 43, a controller 50, and a UI device 60.

The bonding head 12 includes an ultrasonic horn 24 and a clamper 34. The ultrasonic horn 24 is a rod-like member composed of a proximal portion, a flange portion, a horn portion, and a distal portion from the proximal end to the distal end. An ultrasonic oscillator 26 that vibrates according to a drive signal from the controller 50 is arranged at the proximal end. The flange portion is attached to the moving mechanism 18 so as to resonate at a node of the ultrasonic vibration. The horn portion is an arm that extends longer than the diameter of the base end portion, and has a structure that expands the amplitude of vibration generated by the ultrasonic oscillator 26 and transmits it to the tip end portion. A capillary 30 is replaceably attached to the tip. The capillary 30 is a tubular member through which the wire W is inserted. The ultrasonic horn 24 as a whole has a resonant structure that resonates with the vibration of the ultrasonic oscillator 26. The ultrasonic oscillator 26 and the flange are positioned at vibration nodes during resonance, and the capillary 30 is positioned at the vibration antinode. It is structured like this. With these configurations, the ultrasonic horn 24 functions as a transducer that converts electrical drive signals into mechanical vibrations.

The clamper 34 has a piezoelectric element that performs opening and closing operations based on a control signal from the controller 50, and is configured to grip and release the wire W at predetermined timings. This clamper 34 can move together with the capillary 30 .

The moving mechanism 18 moves the bonding head 12 and thus the capillary 30 horizontally and vertically, and has an XY table and an elevating mechanism (not shown). The moving mechanism 18 has one or more drive motors 22 , and the power output from the drive motors 22 moves the bonding head 12 . A position sensor 28 detects the position of the capillary 30 .

The rotating spool 42 replaceably holds the reel around which the wire W is wound. The rotating spool 42 is configured to let out the wire W according to the progress of bonding. The material of the wire W is selected for ease of processing and low electrical resistance. As a material of the wire W, gold (Au), silver (Ag), aluminum (Al), copper (Cu), or the like is usually used.

The torch electrode 43 is connected to a high voltage power source (not shown) through a discharge stabilizing resistor (not shown). The torch electrode 43 generates a spark (discharge) based on a control signal from the controller 50, and the heat of the spark causes a ball, that is, FAB (Free Air Ball) to be formed at the tip of the wire W drawn out from the tip of the capillary 30. Form.

The stage 14 supports the substrate 100. A semiconductor chip 110 is mounted in advance on the substrate. A heater 46 is provided inside the stage 14 to heat the substrate 100 and the semiconductor chip 110 to a temperature suitable for bonding.

The UI device 60 is a device that receives operation input from the operator and outputs information to the operator. This UI device 60 has an input device 62 and an output device 64 . The input device 62 receives operation input from the operator, and has, for example, a keyboard, mouse, trackball, touch panel, joystick, and the like. The output device 64 outputs information to the operator, and has, for example, a display, a speaker, a printer, and the like.

The controller 50 controls driving of the manufacturing apparatus 10 based on a predetermined software program. Specifically, the controller 50 specifically controls the position of the capillary 30 by driving and controlling the moving mechanism 18 . The controller 50 also performs opening/closing control of the clamper 34, application control of the discharge voltage, and driving control of the heater 46 of the stage 14 according to the progress of the bonding process. In the process of wire bonding, a second bonder process of bonding the wire W to the second bond point B2 and a tail cut process of cutting the tail of the wire W are performed. , a predetermined evaluation index indicating the quality of the operating conditions in the tail cut process is also measured. As the evaluation indices, the rupture index Sb and the rupture distance Ds correspond, and these will be explained in detail later. Note that the controller 50 is physically a computer having a processor 52 that executes various calculations and a memory 54 that stores programs and data.

Next, the flow of wire bonding performed by the manufacturing apparatus 10 will be described. 2A to 22F are image diagrams showing the flow of wire bonding. In wire bonding, a wire W is used to connect between the first bonding point B1 and the second bonding point B2. The first bond point B1 is a pad provided on the upper surface of the semiconductor chip 110, and the second bond point B2 is a lead provided on the surface of the substrate 100. FIG.

During wire bonding, the controller 50 forms an FAB at the end of the wire W, as shown in FIG. 2A. That is, a torch electrode 43 applied with a predetermined high voltage is brought close to a part of the wire W extending from the tip of the capillary 30 to generate electric discharge between the tip of the wire W and the torch electrode 43 . This discharge causes the tip of the wire W to melt. The molten wire material then forms a spherical FAB due to surface forces.

Subsequently, the controller 50 executes the 1st bonder to bond the FAB to the first bond point B1, as shown in FIG. 2B. That is, the controller 50 moves the capillary 30 directly above the first bond point B1. After that, the controller 50 lowers the capillary 30 to bring the FAB into contact with the first bonding point B1 and press the FAB with the tip surface of the capillary 30 . At this time, the controller 50 drives the ultrasonic oscillator 26 to generate ultrasonic vibrations in the ultrasonic horn 24 and apply ultrasonic vibrations to the FAB. Furthermore, the controller 50 turns on the heater 46 of the stage 14 to heat the substrate 100 and the semiconductor chip 110 to a predetermined temperature. As a result, the FAB is subjected to load, ultrasonic vibration, and heat from the heater 46, thereby bonding the FAB to the first bonding point B1.

Next, as shown in FIG. 2C, the controller 50 forms a loop connecting the first bond point B1 and the second bond point B2 by moving the capillary 30 along a predefined locus. That is, by moving the capillary 30 with the clamper 34 open, the wire W is let out from the rotating spool 42 to form a loop.

Next, the controller 50 executes a second bonder that bonds the wire W to the second bond point B2, as shown in FIG. 2D. Specifically, the controller 50 causes the capillary 30 to land on the second bonding point B2, and presses the wire W with the tip surface of the capillary 30 against the second bonding point B2. At the same time, the ultrasonic oscillator 26 is driven to apply ultrasonic vibration to the tip of the capillary 30 . Then, the wire W is bonded to the second bonding point B2 by this ultrasonic vibration, load and heat from the heater 46 .

After the wire W is bonded to the second bond point B2, the controller 50 then forms a tail, as shown in FIG. 2E. Specifically, the controller 50 moves the capillary 30 away from the substrate 100 while the clamper 34 is open. This movement forms a tail, which is a portion of wire extending from the tip of capillary 30 . Also, the amount of movement is determined according to the required tail distance.

If the tail can be formed, the controller 50 cuts the tail as shown in FIG. 2F. Specifically, the controller 50 moves the capillary 30 away from the substrate 100 while the clamper 34 is closed. Thereby, the wire W is torn off. Thereafter, similar processing is repeated.

Here, as is clear from the above description, the wire W is mechanically pulled and torn off in the tail cut process after the second bonder process and tail forming process. When the wire is torn off, a reaction force acts on the wire W inserted through the capillary 30 . If this reaction force is excessive, an S-shaped bend occurs in which the wire W inserted through the capillary 30 is bent in an S-shape. In addition, depending on the bonding strength of the wire W and the operating conditions of the tail forming process and the tail cutting process, problems such as a no-tail in which the tail is less than the desired length and lead non-bonding in which the bonding point is peeled off occur. Problems such as S-shaped bending, no tail, and lead non-bonding (hereinafter collectively referred to as "disconnection defects") lead to deterioration in the quality of semiconductor devices.

Therefore, conventionally, operators adjust the operating conditions in the second bonder process, tail forming process, and tail cutting process so as not to cause poor cutting. Here, the operating conditions include, for example, the load value applied to the wire W, the speed at which the capillary 30 is moved, the movement trajectory of the capillary 30, the heating temperature of the heater 46, and the like.

The operator adjusts the operating conditions according to the presence or absence of cutting defects, but conventionally there was no index for quantitatively evaluating the quality of these operating conditions. Therefore, conventionally, the operator has to check the presence or absence of cutting defects by looking at the actually manufactured product, and adjust the operating conditions according to the confirmation result, which is very troublesome.

Therefore, in this specification, the fracture index Sb and the fracture distance Ds are measured as evaluation indices for quantitatively evaluating the quality of the operating conditions, particularly the quality of the operating conditions in the second bonder process, the tail forming process, and the tail cutting process. , and presents the measurement results to the operator. This will be explained in detail below.

First, the fracture index Sb and the fracture distance Ds will be explained. As described above, in this example, after the second bonder process and the tail forming process are completed, the tail cutting process is performed. In this tail cutting process, the controller 50 closes the clamper 34 and moves the capillary 30 away from the second bond point B2 to cut the tail. In this example, a parameter indicating the force required to cut the tail is acquired as the fracture index Sb. Also, the moving distance of the capillary 30 from when the clamper 34 is closed until the tail is cut is acquired as the breaking distance Ds.

More specifically, the controller 50 generates a command position P* that causes the capillary 30 to gradually move in the separation direction during the tail cutting process, and inputs it to the moving mechanism 18 . A driver of the drive motor 22 provided in the moving mechanism 18 calculates a position deviation ΔP, which is the difference between the command position P* and the detected position Pd detected by the position sensor 28, and calculates a value corresponding to the position deviation ΔP. is applied to the drive motor 22 . The drive motor 22 outputs torque proportional to the applied current. When the tail is cut by the output of torque, the reaction causes the capillary 30 to temporarily overshoot greatly in the separation direction.

FIG. 3 is a diagram showing an example of temporal changes in the positional deviation ΔP obtained during the tail cut process. In the example of FIG. 3, the tail is cut at time t1, and the position deviation ΔP peaks immediately after time t1. This peak becomes larger as the recoil at the time of cutting is larger, and as a result, the force required for cutting is larger. Therefore, in this example, the peak value of the positional deviation ΔP is measured as the fracture index Sb. Also, the moving distance of the capillary 30 until this peak value is obtained is measured as the breaking distance Ds. The breaking index Sb and the breaking distance Ds can be used as indices indicating the magnitude of the force required to break the wire W, that is, the breaking strength.

Here, the fracture index Sb and the fracture distance Ds greatly affect the presence or absence of poor bonding. For example, when an S-shaped bend occurs, the fracture index Sb and the fracture distance Ds are larger than when no S-shaped bend occurs. In particular, when the wire W is of the same type, S-shaped bending occurs when the breakage index Sb exceeds a certain value. Therefore, the presence or absence of S-shaped bending can be determined by monitoring the fracture index Sb. Note that the maximum value of the fracture index Sb at which no S-shaped bend occurs (hereinafter referred to as “permissible maximum strength Smax”) varies depending on the type of wire W. As shown in FIG. When the wire W has the same composition, the larger the diameter of the wire W, the larger the allowable maximum strength Smax. In addition, when there is a lead failure where the wire W is not properly bonded to the second bonding point B2, there is no significant difference in the fracture index Sb compared to when there is no lead failure. The distance Ds increases. Accordingly, by monitoring the breaking distance Ds, it is possible to determine the presence or absence of lead non-bonding.

The controller 50 measures the rupture index Sb and the rupture distance Ds, and presents the measurement results to the operator via the output device 64. The operator can determine the presence or absence of joint failure, and thus the quality of the operating conditions, based on the presented fracture index Sb and fracture distance Ds. Note that the range of values of the fracture index Sb and the fracture distance Ds in which poor bonding does not occur, that is, the permissible range varies depending on the type of wire W (ie, composition, diameter, manufacturing method, etc.), and is determined in advance by experiment or the like.

Next, the user interface in the manufacturing apparatus 10 of this example will be explained. In the manufacturing apparatus 10 of this example, a measurement mode is prepared for measuring the evaluation indices of the operating conditions described above, that is, the rupture index Sb and the rupture distance Ds. When the operator selects the measurement mode, the display shows the measurement mode screen 70 shown in FIG. On the measurement mode screen 70, the operator can specify a start number 71, which is the wire number for starting the measurement of the evaluation index, and a measurement number 72, which is the number of wires to be measured. Also, the operator can set different operating conditions for each wire number in advance.

When the start button is selected, the controller 50 performs wire bonding processing in order from the designated wire number to the number of pieces to be measured. In the example of FIG. 4, the starting number is 81 and the number of measurements is 15, so the controller 50 performs the bonding process for 15 wires W with wire numbers 81-85.

The controller 50 measures the rupture index Sb and the rupture distance Ds as evaluation indices for each bonding process, and temporarily stores the results in the memory 54 . When the bonding process for the specified number of measurements is completed, the controller 50 presents the measurement results to the operator. Since a plurality of rupture indices Sb and rupture distances Ds can be obtained (that is, the number of measurements), the controller 50 presents statistical values of the plurality of rupture indices Sb and rupture distances Ds to the operator as measurement results. In the example of FIG. 4, the final value, maximum value, minimum value, average value, and standard deviation of a plurality of rupture indexes Sb and rupture distances Ds are displayed in the measurement result column 73 as the measurement results.

A graph button 74 is also provided on the measurement mode screen 70 . When this graph button 74 is selected, the operator is presented with a plurality of measured values of the rupture index Sb and the rupture distance Ds in graph form. 5A and 5B are diagrams showing examples of graph screens of the rupture index Sb and the rupture distance Ds, respectively, presented to the operator. As shown in FIGS. 5A and 5B, the graph screen has a field 75 for selecting the type of evaluation index to be displayed, and a graph of the selected type of evaluation index is displayed. In the graph, the horizontal axis is the wire number, and the vertical axis is the measurement value of the evaluation index (that is, the fracture index Sb or the fracture distance Ds).

By referring to such a graph, the operator can easily identify the wire numbers with defective joints. In the examples of FIGS. 5A and 5B, the wire number 88 has both high fracture index Sb and high fracture distance Ds, so it can be inferred that S-shaped bending has occurred. Wire No. 91 does not have a high fracture index Sb, but has a high fracture distance Ds. By determining the presence or absence of poor bonding based on the evaluation index in this way, the operator can more easily determine whether the operating conditions are appropriate or not, and can more easily adjust the operating conditions. If the range of the evaluation index in which poor bonding does not occur, that is, the allowable range is known, the upper limit and lower limit of the allowable range may be displayed on the graph. With such a configuration, the operator can more intuitively determine whether the bonding conditions are appropriate.

If the operating conditions can be adjusted by referring to these graphs, the operator will start mass production of the product under the adjusted operating conditions. At this time, the operating conditions are adjusted to conditions that do not cause poor bonding. However, as products are manufactured repeatedly, defective bonding may occur due to temperature changes, individual differences between lots, disturbances, and the like. In order to detect the occurrence of such poor bonding, the controller 50 may continuously or intermittently measure the evaluation index. Then, if the evaluation index is out of the prescribed allowable range, the controller 50 may output an alarm and interrupt the production of the product.

FIG. 6 is a flow chart showing the flow of processing by the controller 50 during mass production of products. As shown in FIG. 6, the controller 50 performs bonding of the n-th wire W according to the operating conditions set by the operator (S12). During the bonding process, the controller 50 measures the fracture index Sb. Then, the obtained fracture index Sb is compared with a predetermined allowable maximum strength Smax (S14). As a result of the comparison, if Sb≦Smax, it is determined that there is no problem, and the next wire W bonding process is executed (S16, S18, S12). On the other hand, when Sb>Smax, there is a high possibility that an S-shaped bend has occurred. In this case, the controller 50 outputs an alarm (S20) and suspends production of the product.

In this way, by monitoring the fracture index Sb during the mass production process of the product, it is possible to detect joining defects at an early stage and further improve the quality of the final product. In FIG. 6, only the rupture index Sb is monitored, but of course, the rupture distance Ds may also be managed in addition to the rupture index Sb. Further, in the description so far, the manufacturing apparatus 10 that performs wire bonding has been described as an example. Apparatus may be applied. Therefore, the technology disclosed in this specification may be applied to a bump bonding apparatus that forms bumps on the semiconductor chip 110 .

Also, in the explanation so far, the peak value of the positional deviation ΔP immediately after the tail is cut is obtained as the breakage index Sb. However, the fracture index Sb may be another parameter, such as the applied current value of the drive motor 22 at the time of cutting, as long as it is a parameter representing the force required to cut the tail.

10 manufacturing equipment, 12 bonding head, 14 stage, 18 movement mechanism, 22 drive motor, 24 ultrasonic horn, 26 ultrasonic oscillator, 28 position sensor, 30 capillary, 34 clamper, 42 rotating spool, 43 torch electrode, 46 heater, 50 controller, 52 processor, 54 memory, 60 UI device, 62 input device, 64 output device, 70 measurement mode screen, 71 start number, 72 number of measurements, 73 measurement result column, 74 graph button, 75 type selection column, 100 circuit board , 110 semiconductor chip, B1 first bond point, B2 second bond point.

Claims

a capillary through which a wire is inserted and which presses and joins the wire extending from the tip to a target surface;
a clamper that moves in conjunction with the capillary and grips the wire;
a moving mechanism having one or more drive motors and moving the capillary with the power of the drive motors;
a position sensor that detects the position of the capillary as a detection position;
a controller that controls driving of the capillary, the clamper, and the movement mechanism;
wherein the controller comprises:
a tail cutting process in which, after joining the wire to the target surface and forming the tail, the tail is cut by moving the capillary in the separating direction with the clamper closed;
an index measurement process of measuring, as a breakage index, the peak value of the deviation between the commanded position for movement of the capillary immediately after the wire is cut and the detected position, or the current value of the drive motor when the wire is cut;
A manufacturing apparatus for a semiconductor device, characterized in that it is configured to execute:
The semiconductor device manufacturing apparatus according to claim 1,
In the index measurement process, the controller also measures a breaking distance, which is a moving distance of the capillary from when the clamper is closed until the wire is cut.
A semiconductor device manufacturing apparatus characterized by:
3. The semiconductor device manufacturing apparatus according to claim 1, further comprising:
A UI device that receives an operation input from an operator and outputs information to the operator,
When the operator instructs measurement of the rupture index, the controller repeats the tail cut process two or more times, and measures the rupture index obtained in each of the two or more tail cut processes. is presented to the operator via the UI device,
A semiconductor device manufacturing apparatus characterized by:
The semiconductor device manufacturing apparatus according to claim 3,
The semiconductor device manufacturing apparatus, wherein the controller presents, in a graph format, a list of the measurement values of the fracture index obtained in each of the tail cutting processes two or more times.
The semiconductor device manufacturing apparatus according to any one of claims 1 to 4,
The manufacturing apparatus of a semiconductor device, wherein the controller outputs an alarm when the fracture index is out of a predetermined reference range.
a tail cutting step of moving the capillary in a direction away from the target surface after the wire extending from the tip of the capillary is pressed against the target surface to be joined, and then the clamper is closed and the wire is gripped;
The peak value of the deviation between the commanded position for movement of the capillary immediately after cutting the wire and the detected position, or the current value of the drive motor at the time of cutting the wire, is executed in parallel with the tail cutting process. an index measuring step of measuring as a fracture index;
comprising
A method of manufacturing a semiconductor device, characterized by: