HK1171573B - Method for applying liquid material and application device - Google Patents

Description

Method and apparatus for applying liquid material

Technical Field

The present invention relates to a liquid material coating method, a liquid material coating apparatus, and a liquid material program for filling a gap between a substrate and a work placed on the substrate with a liquid material discharged from a discharge apparatus by utilizing a capillary phenomenon, and relates to a liquid material coating method, a liquid material coating apparatus, and a liquid material program for stabilizing a coating shape (fillet shape) without changing a moving speed of the discharge apparatus in, for example, an underfill process of a semiconductor package.

In the present specification, the "discharge amount" refers to the amount of the liquid material discharged from the nozzle at the time of one discharge, and the "application amount" refers to the amount of the liquid material required in a fixed range (for example, a coating pattern or a coating region) where a plurality of discharges are performed.

Background

As a mounting technique of a semiconductor chip, there is a technique called a flip chip method. In the flip chip method, a protruding electrode (bump) is formed on the surface of a semiconductor chip and directly connected to an electrode pad on a substrate.

In the flip chip package, in order to prevent the connection portion 33 from being broken by concentration of stress generated by the difference in thermal expansion coefficient between the semiconductor chip 30 and the substrate 29 on the connection portion 33, the connection portion 33 is reinforced by filling the gap between the semiconductor chip 30 and the substrate 29 with the resin 34. This step is referred to as underfill (refer to fig. 6).

The underfill step is performed by applying a liquid resin 34 along the outer periphery of the semiconductor chip 30, filling the gap between the semiconductor chip 30 and the substrate 29 with the resin 34 by capillary action, and then heating the resin 34 in an oven or the like to cure the resin 34.

When the underfill is performed, a rounded portion 35 filled with the liquid resin 34 can be formed at a corner portion formed between the side surface of the semiconductor chip 30 and the substrate 29. This fillet portion is referred to as a fillet (see fig. 7). If the fillet 35 is not formed uniformly, there are problems that air enters from a small portion of the fillet 35 and causes entrainment of air bubbles, that the resin 34 even overflows to a coating-prohibited region around the coating target chip 30, and that the semiconductor chip 30 is damaged during heat curing. Therefore, the fillet 35 must be uniformly formed with a fixed width (symbol 36) and height (symbol 37).

As a technique for forming the fillet uniformly, a technique described in patent document 1 and a technique described in patent document 2 have been proposed (disclosed).

That is, patent document 1 discloses a method for manufacturing a semiconductor package having a structure in which a space between a semiconductor chip and a mounting board is filled with a resin, wherein the speed of a nozzle for supplying the resin is adjusted so that the resin supplied from one side of the semiconductor chip is larger in the center portion of the semiconductor chip than in the end portions of the semiconductor chip.

Patent document 2 discloses a method of moving a nozzle around a semiconductor chip flip-chip bonded to a wiring board, continuously supplying an underfill material from the nozzle, and filling the underfill material between the wiring board and the semiconductor chip, wherein a movement trajectory of the nozzle is such that a linear trajectory located within a range of a pair of line segments drawn at right angles to a side of the semiconductor chip from both ends of the side and a direction change trajectory for changing a direction to connect mutually adjacent linear trajectories are continuous, and the nozzle is moved slowly in at least a part of the linear trajectory compared to the direction change trajectory.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 10-50769

Patent document 2: japanese laid-open patent publication No. 2008-71883

Disclosure of Invention

(problems to be solved by the invention)

The technique for adjusting the supply amount disclosed in patent document 1 or patent document 2 is performed by adjusting the moving speed of the nozzle in the process of applying and drawing the liquid resin supplied from the nozzle.

However, changing the nozzle moving speed during the coating drawing process has a problem that a large load is imposed on the driving unit and an excessive load is consumed as the speed difference between the nozzle moving speeds is large, thereby shortening the life of the driving unit. Further, there is also a problem that the supply amount is adjusted by the moving speed of the nozzle, and the control becomes complicated. Further, there is also a problem that the change of the nozzle moving speed during the coating drawing causes unnecessary vibration of the apparatus and deteriorates the coating accuracy.

Accordingly, an object of the present invention is to provide a coating method, an apparatus, and a program which can eliminate a difference in penetration when bumps are unevenly arranged and a disturbance in the fillet shape due to a speed difference associated with switching of the nozzle direction, and can keep the fillet shape constant.

(means for solving the problems)

In order to solve the above problems, the inventors have found that the reason why the inner fillet shape is disturbed is also the arrangement of the bumps 31 formed on the semiconductor chip 30. As described above, in the underfill step, the liquid resin 34 is filled in the gap between the semiconductor chip 30 and the substrate 29 by the capillary phenomenon. The degree of penetration of the liquid resin 34 into the gap is affected by the width of the gap and also by the arrangement density of the bumps 31 present inside the gap. For example, a semiconductor chip 30 having a difference in density of the arrangement of bumps 31 as shown in fig. 8 is considered. Coating is performed along one side of the semiconductor chip 30. In general, the penetration of the liquid resin 34 is fast in the portions 38 where the bumps 31 are densely arranged, and the penetration of the liquid resin 34 is slow in the portions 39 where the bumps 31 are sparsely arranged. Therefore, if coating is performed in which the amount of coating per unit area is set to a fixed amount as in fig. 8(a), fillets having uneven widths or uneven heights are formed due to the difference in the degree of penetration as described above, and thus fillet shape disorder as in fig. 8(b) may occur.

Another cause of the disturbance of the fillet shape is an influence of a change in the moving speed during the coating operation. When coating is performed on a trajectory in which the moving direction changes, such as an L-shape or a U-shape, the speed must be reduced at the corner (direction changing portion) for the direction change. Therefore, if a fixed amount of coating is performed, as shown in fig. 9, the amount of coating at the corner portion increases, and the fillet shape is disturbed.

In fact, as shown in fig. 10, the bump arrangement described above interacts with the deceleration of the corner portion, and becomes a more disturbed fillet shape.

As described above, the inventors established an assumption that can be solved by changing the coating amount per unit area in the coating target region based on the inference that the arrangement of the bumps 31 formed on the semiconductor chip 30 and the fillet shape formed by underfilling the semiconductor chip 30 are related to each other, and verified the assumption.

As a result, it was found that it is effective to adjust the amount of supply from the discharge device in order to change the amount of application per unit area in the area to be coated. That is, it was found that in order to uniformly form the fillet shape without being affected by the bump arrangement, it is important to coat the coating target region with an amount necessary per unit area thereof.

Further, it was found that in order to uniformly form the fillet shape without being affected by the speed change accompanying the direction change or the like, it is important to supply the coating target region with an amount necessary per unit area thereof.

Further, as a method for changing the amount of coating per unit area in the coating target region on the side of the discharge device, a discharge device of a type that ejects droplets or discharges droplets by flying from the discharge device is effective, and the inventors have made extensive studies based on this finding and completed the present invention.

That is, the method for applying a liquid material according to claim 1 of the present invention is a method for applying a liquid material, in which a desired application pattern is formed, the liquid material is discharged from a nozzle while relatively moving the nozzle and a workpiece, and the liquid material is filled in a gap between a substrate and the workpiece mounted on the substrate via 3 or more bumps by utilizing a capillary phenomenon, wherein, when the bumps are unevenly arranged, a supply amount per unit area in the application pattern is set so that a supply amount of an application region adjacent to a region having a high bump concentration is larger than a supply amount of an application region adjacent to a region having a low bump concentration.

The method for applying a liquid material according to claim 2 is characterized in that, in the invention 1, the supply amount of the application region adjacent to the region having a high degree of aggregation of bumps is increased as compared with the application region adjacent to the region having a low degree of aggregation of bumps.

The method for applying a liquid material according to claim 3 is characterized in that, in the invention according to claim 1 or 2, the supply amount of the application region adjacent to the region having a low degree of bump aggregation is reduced as compared with the application region adjacent to the region having a high degree of bump aggregation.

A liquid material coating method according to claim 4 of the present invention is a liquid material coating method for forming a desired coating pattern by discharging a liquid material from a nozzle while relatively moving the nozzle and a workpiece, and filling a gap between the substrate and the workpiece mounted on the substrate via 3 or more bumps with the liquid material by using a capillary phenomenon, the liquid material coating method including: an initial parameter setting step of defining the number of times of sending the ejection pulse signal and the stop pulse signal as a total pulse number, defining the number of ejection pulse signals necessary for achieving the coating amount among the total pulse number, and defining the rest as the stop pulse signal; a correction amount calculation step of measuring an ejection amount from the ejection device and calculating a correction amount of the ejection amount; and an ejection amount correction step of adjusting the number of ejection pulse signals and the number of stop pulse signals based on the correction amount calculated in the correction amount calculation step; the ejection rate correction step adjusts the number of ejection pulse signals per unit area of the coating region adjacent to the region having the high degree of bump aggregation to be larger than the number of ejection pulse signals per unit area of the coating region adjacent to the region having the low degree of bump aggregation when the bumps are unevenly arranged.

A method for applying a liquid material according to claim 5 of the present invention is a method for applying a liquid material, in which a liquid material is discharged from a nozzle while relatively moving the nozzle and a workpiece, and the liquid material is filled in a gap between a substrate and the workpiece mounted on the substrate via 3 or more bumps by utilizing a capillary phenomenon, the method comprising: a coating pattern making step of making a coating pattern composed of a plurality of continuous coating areas; an ejection cycle allocation step of allocating, to each application region, an ejection cycle in which a plurality of ejection pulse signal numbers and a plurality of stop pulse signal numbers are combined at a predetermined ratio; a correction amount calculation step of measuring an ejection amount from the ejection device and calculating a correction amount of the ejection amount; and a discharge amount correction step consisting of: when the bumps are unevenly arranged, adjusting the number of the ejection pulse signals and the number of the stop pulse signals included in the coating pattern so that the supply amount per unit area of the coating region adjacent to the region having the high bump concentration is larger than that of the coating region adjacent to the region having the low bump concentration, based on the correction amount calculated in the correction amount calculation step; and/or adjusting the length of at least the one coating region and the other one or two coating regions continuous with the one coating region without changing the ejection amount per unit time in each coating region.

The method for applying a liquid material according to claim 6 of the present invention is characterized in that, in the invention according to claim 4 or 5, the ejection amount is corrected without changing the frequency at which the ejection pulse signal and the stop pulse signal are transmitted.

A liquid material application method according to claim 7 of the present invention is a liquid material application method for forming a desired application pattern by discharging a liquid material from a nozzle while relatively moving the nozzle and a workpiece, and filling a gap between the substrate and the workpiece mounted on the substrate via 3 or more bumps with the liquid material by utilizing a capillary phenomenon, the liquid material application method including: an initial parameter setting step of defining intervals between unit periods for performing one ejection; a correction amount calculation step of measuring an ejection amount from the ejection device and calculating a correction amount of the ejection amount; when the bumps are unevenly arranged, the unit cycle interval included in the application pattern is adjusted so that the supply amount per unit area of the application region adjacent to the region having a high degree of bump aggregation is larger than that of the application region adjacent to the region having a low degree of bump aggregation, based on the correction amount calculated in the correction amount calculation step.

The method for applying a liquid material according to claim 8 of the present invention is characterized in that, in any one of the aspects 1 to 7 of the present invention, when the application pattern is an application pattern that does not require switching of the nozzle direction, the application is performed without changing the relative movement speed of the nozzle and the workpiece.

The method for applying a liquid material according to claim 9 of the present invention is characterized in that, in any one of the aspects 1 to 7, when the application pattern is an application pattern including an application region requiring nozzle direction switching, the supply amount per unit area in the application pattern is set so that the liquid material is increased in the application region requiring no nozzle direction switching as compared with the application region requiring nozzle direction switching.

A liquid material application device according to claim 10 of the present invention is an application device including a discharge device having a nozzle, a drive mechanism for moving the discharge device and a workpiece relative to each other, a detection device for detecting a shape of a liquid material to be applied, and a control unit for controlling these operations; the liquid material application apparatus is characterized in that the control unit performs the application method according to any one of aspects 1 to 9 of the present invention.

The program according to claim 11 of the present invention is a program for causing a control section to execute the application method according to any one of claims 1 to 9 in an application device including a discharge device having a nozzle, a drive mechanism for moving the discharge device and a workpiece relative to each other, a detection device for detecting a shape of a liquid material to be applied, and a control section for controlling these operations.

(Effect of the invention)

According to the present invention, the difference in penetration when the bumps are unevenly arranged, or the disturbance of the fillet shape due to the speed difference associated with the switching of the nozzle direction can be eliminated, and the fillet shape can be kept constant.

In addition, since the relative movement speed of the nozzle does not need to be changed except for the direction change, the load applied to the driving mechanism can be reduced, and thus the generation of vibration can be suppressed and the accuracy can be improved.

Drawings

Fig. 1 is a flowchart showing a procedure of adjusting the supply amount of the liquid material according to the present invention.

Fig. 2 is a sectional view of an essential part of the ejector-type sprayer of the embodiment.

Fig. 3 is an explanatory diagram for explaining a pulse signal to be transmitted to the ejection device of the embodiment.

Fig. 4 is a schematic perspective view of the coating apparatus of the embodiment.

Fig. 5 is a flowchart showing a coating operation sequence in the coating apparatus of the embodiment.

Fig. 6 is a side sectional view for explaining the underfill step.

FIG. 7 is a side sectional view for explaining the fillet.

Fig. 8 is a partial perspective top view for explaining the influence of the bump arrangement on the inner rounded shape. (a) The partial perspective plan view is a partial perspective plan view for explaining a state in which semiconductor chips having a difference in bump arrangement density are coated with a fixed amount of coating per unit area. (b) The partial perspective plan view is a partial perspective plan view for explaining the inner fillet shape of the semiconductor chip having a difference in bump arrangement density after coating by setting the coating amount per unit area to a fixed amount.

Fig. 9 is a plan view for explaining the influence of the change in the moving speed on the inner rounded shape.

Fig. 10 is a partial perspective plan view for explaining the influence of the inner rounded shape when the bump arrangement and the moving speed change are combined.

Fig. 11 is a plan view for explaining adjustment of a speed change portion. (a) The top view is a plan view illustrating an application pattern in which the supply amount per unit area is reduced at the corner portion. (b) The top view is a plan view for explaining the inner rounded shape after coating with a coating pattern in which the amount of supply per unit area is reduced at the corner portion.

Fig. 12 is a partial perspective top view for explaining adjustment of different portions in a case where there is a difference in bump arrangement density in the vicinity of the edge of a semiconductor chip to cause penetration. (a) The partial perspective plan view is used to describe the application pattern in which the supply amount per unit area is increased or decreased according to the bump density. (b) The partial perspective plan view is a partial perspective plan view for explaining the fillet shape after coating with a coating pattern that increases and decreases the supply amount per unit area in accordance with the bump pitch.

Fig. 13 is a partial perspective top view for explaining adjustment of different portions in a case where there is a difference in bump arrangement density inside a semiconductor chip to cause penetration. (a) The partial perspective plan view is a partial perspective plan view for explaining the fillet shape of the semiconductor chip coated with the coating amount per unit area set to a fixed amount for the semiconductor chip having a difference in the arrangement density of bumps inside the semiconductor chip. (b) The partial perspective plan view is used to describe the application pattern in which the supply amount per unit area is increased or decreased according to the bump density. (c) The partial perspective plan view is a partial perspective plan view for explaining the fillet shape after coating with a coating pattern that increases and decreases the supply amount per unit area in accordance with the bump pitch.

Fig. 14 is a diagram showing an example of a coating pattern by dot coating.

Fig. 15 is a diagram showing an example of a coating pattern in which a coating region is divided into a plurality of regions in line coating and the coating amount is changed for each coating region. (a) The length of each coated region in the coating pattern is illustrated. (b) The discharge amount per unit length in each coating region before correction is described. (c) The discharge amount per unit length in each coating region after correction is illustrated.

Description of the symbols

1 discharge device

2 piston

3 storage container

4 nozzle

5 nozzle inlet

6 switching valve

7 spring

8-stroke adjusting unit

9 Heater

10 temperature sensor

11 control part

12 gas piping

13 electric wiring

14 ejection pulse

15 stop pulse

16 coating device

17 XYZ driving mechanism

18 conveying mechanism

19 coating platform

20 substrate for adjustment

21 platform for adjustment

22 weighing apparatus

23 touch sensor

24 laser displacement meter

25 Camera

26 direction of movement

27 carrying-in direction

28 direction of carrying-out

29 substrate

30 workpiece (semiconductor chip)

31 projecting electrode and projection

32 electrode pad

33 connecting part

34 resin, liquid material

35 round corner part and fillet

Width of 36 inner round angle

37 fillet height

38 the part with more dense bumps

39 sparse part of bump

40 coating direction

101 workpiece (semiconductor chip)

141 coating area

142 non-coated area

151 first coating region

152 second coating zone.

Detailed Description

The following describes embodiments of the present invention.

The discharge device used in the present embodiment is a jet type discharge device that receives a pulse signal to drive a valve body and causes the valve body to collide with a valve seat, thereby causing a liquid material to be ejected from a nozzle in a flying manner. In this ejection device, one ejection is performed by receiving one pulse signal. In the present embodiment, the pulse signal is transmitted at a frequency set in advance to perform coating.

The procedure of adjusting the amount of coating per unit area (or per unit length) in the coating target region in the discharge device of the present embodiment will be described (see fig. 1). The present invention is applicable to any type of discharge device that performs flying discharge or droplet discharge, and is not limited to application to the jet type.

(1) Setting of necessary coating amount (step 101)

First, the amount of the liquid material necessary for filling the gap between the substrate and the workpiece to form the fillet is determined. The necessary amount may be obtained by obtaining a theoretical value based on a design drawing or the like, or may be obtained by actually performing coating. Here, since the theoretical value is always an ideal value, it is preferable to obtain the theoretical value by actually performing coating in order to expect accuracy. The necessary amount may be determined as a volume or a mass. At this time, a value of the density of the liquid material used is necessary.

Then, the time required for discharging the necessary amount is obtained from the amount discharged by one discharge and the time required for one discharge. Here, the amount of discharge and the time required for one discharge are determined by the properties of the liquid material, the shape (diameter and length) of the nozzle, the amount of movement (stroke) of the valve element, and the like, and it is preferable to measure the amount of discharge by actually performing the discharge. In this case, the accuracy can be improved by performing a plurality of ejections to obtain an average value.

(2) Setting of coating Pattern (step 102)

The edge for coating is set in consideration of the arrangement of bumps (connection portions) connecting the workpiece and the substrate, the condition of other parts around the workpiece, and the like. For example, a rectangular workpiece is set to be coated linearly along one side or L-shaped along two adjacent sides. The pattern thus obtained is set to be a coating pattern.

Then, if the coating pattern is determined, the coating length is determined. From the coating length and the discharge time obtained in (1), the moving speed at which the coating pattern is completely uniform is temporarily obtained.

(3) Production of coating Pattern (step 103)

The coating pattern is produced by considering the coating amount, coating length, and the like determined by the shape of the work. Here, the "coating length" refers to the total length of the relative movement amount of the nozzle and the workpiece.

The coating pattern is composed of at least one ejection pulse and at least 0 stop pulse. A pulse signal composed of an ejection pulse and a stop pulse is transmitted at a predetermined frequency. The frequency corresponds in principle to the number of shots/second. The frequency is preferably set to several tens of hertz or more, and more preferably, several hundreds of hertz.

The frequency is determined by the total length of the coating pattern, the weight and volume of the liquid material 34 necessary for a desired coating pattern, and the like.

(4) Setting of initial parameters (step 104)

The parameters listed below are set as initial parameters.

(i) Blow-out frequency (unit period)

Since the discharge device used in the present embodiment is of a jet type, one discharge is performed by one operation of the valve body. This is set to one unit period. In the present embodiment, the coating is performed by repeating the unit cycle at a predetermined frequency.

The predetermined frequency has an optimum frequency range, and if the predetermined frequency deviates from the optimum frequency range, a problem such as no ejection occurs, and therefore, the range of the normal ejection is experimentally determined in advance. Although the amount of the liquid material to be ejected varies depending on the characteristics of the liquid material, the amount of the liquid material to be ejected may be, for example, about 100 to 200 Hz.

However, the frequency range is determined according to the mechanical response performance and the characteristics of the liquid material. As described above, if the frequency is changed, the discharge rate is changed, but if the frequency is out of the optimum frequency range, there occurs a problem such as non-ejection, and the change characteristic of the discharge rate due to the frequency change is not linear. Therefore, basically, it is preferable not to change the frequency once set in the same coating pattern. However, since the frequency has a certain range as described above, if the frequency is within the range, the discharge amount can be adjusted by changing the frequency.

Specifically, the following is described. It is assumed that the optimum pulse signal is a pulse signal having a unit cycle of 3msec for the on state and 4msec for the off state in order to achieve a desired discharge amount. The cycle frequency is about 142 hz. It is considered that the frequency is different in the same frequency range (about 100 to 200 Hz) based on the period. Here, in order to vary the frequency, the on state time is fixed, and the off state time is varied. First, if it is considered that the time of the off state is sequentially reduced, the frequency is about 166 hz when the time of the off state is 3msec, and the frequency is 200 hz when the time of the off state is 2msec, so that the limit is 2 msec. On the contrary, if it is considered that the time of the off-state is sequentially increased, the frequency is 125 hz when the time of the off-state is 5msec, the frequency is about 111 hz when the time of the off-state is 6msec, the time of the off-state is 7msec, and the frequency is 100 hz, so that the limit is 7 msec. If the range of the time to be in the limit off state is determined, experiments are conducted in advance for setting these plural on/off times, and the relationship between the on/off times and the discharge amount is obtained and stored in the control unit. Then, at the time of adjustment described below, a setting suitable for the adjustment is selected therefrom.

Also, in the above example, the on/off time is set to an integer, but in order to obtain a more accurate and more set value, the on/off time may of course be set to a real number (decimal).

Further, since the value closest to the boundary of the frequency range may be changed to a range in which a problem such as no ejection occurs due to the influence of the characteristics of the liquid material or the change in the ambient temperature, it is preferable to set the on/off time, that is, the frequency, with a margin maintained without the closest value.

(ii) Pulse number (number of ejection and stop pulses)

The number of ejection pulses and the number of stop pulses constituting the coating pattern are set. A control unit stores a setting table in advance, which defines the combination of the number of ejection pulses and the number of stop pulses.

Table 1 is an example of a setting table stored in the control unit. In table 1, a setting example a shows a setting example of the ejection rate when the total pulse number is 100, a setting example B shows a setting example of the ejection rate when the total pulse number is 111, and a setting example C shows a setting example of the ejection rate when the total pulse number is 125. In setting A, B, C, the number of ejection pulses corresponds to the ejection amount, and the ejection amount can be adjusted by increasing or decreasing the number of stop pulses out of the total number of pulses.

The setting example a is a setting example that defines that the ejection rate is changed based on a combination in which the stop pulse is not set for one ejection pulse (0 times of stop pulse) when the number of ejection pulses becomes 100.

The setting example B is a setting example that specifies that the ejection rate is changed based on a combination of stop pulses set once for nine ejection pulses (11 stop pulses) when the number of ejection pulses becomes 100.

The setting example C is a setting example that specifies that the ejection rate is changed based on a combination of stop pulses set once for four ejection pulses (25 stop pulses) when the number of ejection pulses becomes 100.

When the number of stop pulses is increased or decreased in the correction of the ejection amount described below, it is preferable to set the initial parameters so that the timing of the stop pulses becomes equal intervals.

In the underfill step, when the number of stop pulses is increased two or three times, it is preferable to reduce the number of ejection pulses relative to the number of stop pulses and reduce the gap (non-coated region) in comparison with the case where the number of stop pulses is continuously increased to enlarge the gap (non-coated region) in order to prevent the entrainment of bubbles.

[ Table 1]

(5) Setting of coating speed (step 105)

When the coating pattern has a corner portion such as an L-shape or a U-shape, the moving speed of the nozzle at the corner portion is changed in order to reduce the load on the driving mechanism. The reason for this is that: the speed of movement of the nozzle at the corners is limited by the mechanical rigidity of the drive mechanism and typically, the speed of the nozzle needs to be slowed at the corners. On the other hand, the speed set in (2) above is not changed in the portion other than the corner portion. However, when the speed difference between the corner portion and the portion other than the corner portion is large, the change may be performed not in a single step but in several steps.

(6) Blow-out related parameter setting

Adjustment of parameters corresponding to the coating pattern or coating speed and related to the ejection is performed.

The process is divided into the following two stages.

(i) Adjustment of speed change part (step 106)

If the nozzle moving speed is changed, the supply amount per unit area of the portion is changed. Therefore, the original substrate on which no work or other parts are mounted is coated in the pattern set in the above (2), and the coated line width is measured. When there is a portion or section where the measured value of the line width exceeds the allowable range, the parameters related to the discharge in the portion or section are adjusted. In other words, when the line width is wide, parameter adjustment is performed to narrow the line width. On the other hand, when the line width is narrow, parameter adjustment is performed to widen the line width.

For example, when the line width of the corner portion is widened by decelerating the corner portion as shown in fig. 9, the parameter adjustment is performed so that the widened portion and the straight portion have the same width in order to reduce the supply amount per unit area of the corner portion. That is, by forming, as an application pattern, an application pattern in which the supply amount per unit area of the corner portion is small as shown in fig. 11(a), in actual application in which deceleration of the nozzle moving speed occurs, a fillet having a line width equal to that of the straight portion is formed as shown in fig. 11 (b).

The types of parameters to be adjusted will be described later.

(ii) Adjustment of different sites of penetration (step 107)

When an actual object to be coated is coated, the penetration of the liquid material in the coating pattern is different depending on the arrangement of the bumps present in the gap between the work and the substrate. Therefore, the necessary coating amount per unit area may vary. Therefore, the substrate on which the workpiece is mounted is coated in the pattern set in the above (2), and the width of the coated fillet is photographed and measured by the image pickup device. When there is a portion or section where the value of the measured fillet width exceeds the allowable range, the parameters relating to ejection in the portion or section are adjusted. In other words, when the fillet width is wide, parameter adjustment is performed to narrow the fillet width. On the other hand, when the fillet width is narrow, parameter adjustment is performed to widen the fillet width.

For example, when the line width is narrowed at a portion where bumps are dense (a portion where the concentration is high) as shown in fig. 8, parameters are adjusted so that the narrowed portion and a portion where bumps are sparse (a portion where the concentration is low) have the same width in order to increase the supply amount per unit area of the portion where bumps are dense. Here, instead, the parameter may be adjusted to reduce the supply amount per unit area of the locations where the bumps are sparse. As a result of the parameter adjustment, the coating pattern is one in which the supply amount per unit area is large at a portion where the bumps are dense and the supply amount per unit area is small at a portion where the bumps are sparse as shown in fig. 12(a), and a fillet having a constant width is formed in the actual coating where the difference in permeation rate occurs as shown in fig. 12 (b). Further, the fillet height may be measured by imaging with an imaging device, and the parameter adjustment for ejection may be performed based on the measurement result.

In addition, not only the case where the arrangement density of the bumps is different in the edge portion close to the semiconductor chip as in fig. 8 or 12, but also the case where the arrangement density of the bumps is different in the inside (center side) of the semiconductor chip can be considered in the same manner. For example, if the bump arrangement shown in fig. 13 is applied with a nozzle speed and a supply amount per unit area fixed, a problem arises in that the fillet widths (application line widths) are different from each other as shown in fig. 13 a. Therefore, in order to increase the supply amount per unit area of the bump-dense portion or in order to reduce the supply amount per unit area of the bump-sparse portion, parameters are adjusted so that the fillet width (coating line width) of the bump-dense portion and the fillet width (coating line width) of the bump-sparse portion are equal to each other. That is, by making the coating pattern as in fig. 13(b), a fillet of a fixed width as in fig. 13(c) can be formed.

The types of parameters to be adjusted will be described later.

(iii) Kinds of parameters relating to ejection

The following describes changing parameters related to ejection when the adjustment is performed.

(iii-1) Ejection frequency (unit period)

In the ejection in the unit cycle in which the predetermined frequency is repeated, the interval between the unit cycles is adjusted based on the values set in (4) and (i) above in order to change the application amount per unit area. Specifically, if the unit cycle interval is narrowed, the coating amount increases, and if the unit cycle interval is widened, the coating amount decreases. The relationship between the unit cycle interval and the discharge amount is obtained by experiments in advance and is stored in the control unit or the like in the form of a map or a calculation formula as a standard for setting the adjustment amount.

(iii-2) pulse count (ejection and stop)

In the ejection using the pulse signal transmission, in order to change the coating amount per unit area, the coating amount is changed by changing the number of ejection pulse signals and the number of stop pulse signals according to the table set in the above (4) and (ii), in which the number of times of transmitting a signal for performing ejection (i.e., an ejection pulse signal) and a signal for not performing ejection (i.e., a stop pulse signal) is defined as the total number of pulses, the number of ejection pulse signals necessary for achieving the coating amount among the total number of pulses is defined, and the remaining number is defined as a stop pulse signal. Specifically, if the stop pulse signal in the total number of pulses is increased, the coating amount is decreased, and if the stop pulse signal is decreased, the coating amount is increased. The number of ejection pulses and the relationship between the number of stop pulses and the ejection amount are determined by experiments in advance and stored in the control unit in the form of a map or a calculation formula as a criterion for setting the adjustment amount.

By changing the number of pulses, the coating amount can be changed without changing the coating length.

(iii-3) Ejection Rate variation factor of Ejection device

The amount of coating per unit area can also be changed by adjusting the discharge amount changing factor of the discharge device. For example, the discharge amount is changed by adjusting a discharge amount changing factor of a discharge device described below.

1) "pressure" applied to the storage vessel;

2) the distance of travel in one stroke of the valve body, i.e., the "stroke";

3) the "temperature" of the heater that heats the vicinity of the nozzle;

4) the "nozzle diameter" of the nozzle for ejecting the liquid material.

Here, the magnitude of each of the above factors corresponds to the magnitude of the ejection amount of the liquid material.

The parameters (iii-1) to (iii-3) are adjusted to select the optimum parameters based on the results of coating the original substrate or workpiece and measuring the line width or fillet width.

Further, a plurality of parameters may be combined and adjusted in the above-mentioned (iii-1) to (iii-3). For example, the parameter (iii-1) or (iii-3) may be adjusted in an auxiliary manner based on the adjustment of the parameter (iii-2) when the adjustment range reaches a limit, or when fine adjustment is performed.

By performing the above steps 101 to 107, the amount of application per unit area in the area to be coated can be changed, and therefore, the fillet shape can be kept constant while eliminating the disturbance of the fillet shape caused by the influence of the bump arrangement or the influence of the speed change accompanying the direction change.

In addition, since no change in the moving speed is required other than the direction change, the load applied to the drive mechanism can be reduced, and thus the generation of vibration can be suppressed, the accuracy can be improved, and the life can be prolonged.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Examples

[ Ejection device ]

As shown in fig. 2, the ejection device 1 includes: a piston 2 serving as a valve body inscribed to be movable up and down; a storage container 3 pressurized by the compressed gas whose pressure is adjusted by the control unit 11; and a nozzle 4 communicating with the storage container 3. Further, the ejection device 1 includes: a switching valve 6 for supplying and discharging the working gas for moving the piston 2 upward by the control unit 11; and a spring 7 for moving the piston 2 downward. Further, a stroke adjusting member 8 for adjusting the amount of movement of the piston 2 is provided above the spring 7. Further, a heater 9 for heating the nozzle 4 and the liquid material 34 located therein is provided in the vicinity of the nozzle 4. A temperature sensor 10 is provided on the opposite side of the heater 9, and the temperature sensor 10 is used when performing control for keeping the nozzle 4 and the liquid material 34 located therein at a predetermined temperature.

The liquid material 34 filled in the reservoir 3 is ejected in the form of droplets from the nozzle 4 by moving the switching valve 6 in response to the pulse signal transmitted from the control unit 11 and moving the piston 2 up and down. The liquid material 34 ejected from the nozzle 4 is applied in a dot shape to the substrate 29 or the weighing device 22 positioned below the nozzle 4.

The discharge device 1 reciprocates the piston 2 once for each pulse signal, and discharges one drop of the liquid material 34 from the nozzle 4. That is, one unit cycle corresponds to one shot.

For example, a pulse signal is provided as shown in fig. 3. When the pulse signal is on (left side of reference numeral 14), gas is supplied by the operation of the switching valve 6, and the piston 2 is raised to open the nozzle inlet 5. Then, when the pulse signal is turned off (right side of the reference numeral 14), the gas is discharged by the operation of the switching valve 6, and the piston 2 is lowered by the repulsive force of the spring 7 to close the nozzle inlet 5. Then, one drop of the liquid material 34 is ejected by the operation of one unit cycle, with the rise of the piston 2 (opening of the nozzle inlet 5) and the fall of the piston 2 (closing of the nozzle inlet 5) as one unit cycle. On the other hand, when the pulse signal is off (symbol 15), the piston 2 is not actuated, and the nozzle inlet 5 is closed for one unit cycle.

Further, the time of the on state (rising time) and the time of the off state (falling time) in one unit cycle may be adjusted, and the amount of movement of the piston 2 may be adjusted using the stroke adjusting means 8.

When coating is performed along the side of the workpiece 30, the control unit 11 sends a pulse signal to the ejection device 1 at a predetermined frequency while moving the nozzle 4 at the same time as the start of coating, and continuously ejects the liquid material 34. The liquid material 34 ejected along the side of the workpiece 30 fills the gap between the workpiece 30 and the substrate 29 by capillary action.

[ coating apparatus constitution ]

As shown in fig. 4, the coating device 16 of the present embodiment includes: the discharge device 1, the XYZ drive mechanism 17, the transport mechanism 18, the application stage 19, the adjustment substrate 20, the adjustment stage 21 on which the adjustment substrate 20 is placed, the scale 22, the detection device (the touch sensor 23, the laser displacement meter 24, and the camera 25), and the control unit 11.

The discharge device 1 is the above-described ejection type discharge device, and discharges the liquid material 34 in response to a pulse signal from the control unit 11.

The XYZ drive mechanism 17 is provided with the ejection device 1, and a laser displacement meter 24 and a camera 25, which are described below as a part of the detection device, and can move the ejection device 1, the laser displacement meter 24, and the camera 25 in XYZ directions indicated by reference numeral 26. That is, the discharge device 1 may be moved above the substrate 29 in accordance with the application pattern set in the control unit 11, or the discharge device 1, the laser displacement meter 24, and the camera 25 may be moved to a scale 22 or a device such as a touch sensor 23 which is a part of a detection device described below fixed at another position, or an adjustment stage 21 on which the adjustment substrate 20 described below is placed.

The conveying mechanism 18 carries in a substrate 29 on which a workpiece 30 is placed before a coating operation is performed, from a direction indicated by reference numeral 27 outside the apparatus, and conveys the substrate to the vicinity of the discharge apparatus 1 where the coating operation is performed. Then, the substrate 29 on which the coating operation is completed is carried out in a direction indicated by reference numeral 28 outside the apparatus.

The coating surface plate 19 is provided between the conveyance mechanisms 18 at substantially the center of the conveyance mechanisms 18. When the coating operation is performed, the coating surface plate 19 is lifted to function as a fixing plate 29. When the substrate 29 is conveyed, the coating table 19 is lowered without being an obstacle to conveyance.

The adjustment stage 21 is provided in the vicinity of the conveyance mechanism 18. An original substrate or a substrate on which a dummy workpiece is mounted (collectively referred to as an adjustment substrate 20) is placed above the adjustment stage 21, and is used for coating in accordance with an adjustment operation of the supply amount of the liquid material.

The weighing device 22 is provided near the conveyance mechanism 18 for measuring the weight of the liquid material 34 discharged from the discharge apparatus 1. The measurement result of scale 22 is transmitted to control unit 11.

The detection device comprises: a touch sensor 23 as a sensor for detecting the height position of the nozzle 4, a laser displacement meter 24 as a sensor for detecting the height position of the substrate 29, and a camera 25 for detecting the position of the workpiece 30. The laser displacement meter 24 and the camera 25 are provided in the XYZ drive mechanism 17 together with the ejection device 1, and are movable in the XYZ direction. The touch sensor 23 is fixedly disposed on the adjustment platform 21.

The control unit 11 is constituted by an overall control unit that controls the overall operation of the apparatus 16, and a discharge control unit that controls the operation of the discharge device 1.

[ coating operation ]

Next, a flow of a series of coating operations using the coating apparatus will be described. Fig. 5 shows a flow chart of the coating operation. The preparation of the coating pattern will be described later (see fig. 14 and 15 described later).

When the coating operation is started, first, the factors related to the discharge device (i.e., the nozzle diameter, the stroke amount, the applied pressure, and the like) are set in accordance with the target discharge amount for each discharge (step 501). This operation can be performed while actually performing ejection and measuring the ejection amount per ejection, the diameter of the liquid material as a result of application, and the like. In this case, it is also preferable to confirm whether the liquid material is excessively attached to the nozzle tip or whether the liquid material is scattered by dividing into a plurality of pieces as a result of application. The number of ejection pulses and the number of stop pulses are set as initial parameters (see table 1 above).

Then, the deviation of the coating position is corrected (step 502). Here, first, the original substrate is linearly coated, and then the camera is moved only by a preset nozzle-camera distance to photograph the coated liquid material. Then, how much the photographed liquid material is shifted from the center of the camera is measured, and correction is performed by adjusting the shifted portion.

Then, settings related to image recognition of the coating target workpiece are performed (step 503). This setting is a reference for performing alignment (alignment of a distorted or bent position of a workpiece or a substrate).

Then, a series of operations for adjusting the supply amount from the discharge device described in the above embodiment is performed (step 504). That is, as described in the embodiment for carrying out the invention, the supply amount of the liquid material is adjusted by a single or a combination of parameters related to ejection.

Then, the number of portions or the number of portions to be inspected for the presence or absence of a fillet, the width, or the like is set (step 505). In this case, a value to be a reference for the quality determination, such as a target value or an allowable value, is also set.

Then, a value to be a reference is set at the time of correction of the coating amount in the subsequent coating operation (step 506). Here, the weight of the coating material discharged at a predetermined time or the number of shots from the weighing device provided in the coating apparatus is measured and stored in the control unit.

Then, the mounting substrate actually subjected to coating is coated and finally confirmed (step 507). If the coating is not satisfactory after the final confirmation, the coating operation is started (step 508).

When the present coating operation is started, the substrate is first carried in and carried to the vicinity of the discharge device, and then the substrate is fixed to the coating table (step 509). Then, the substrate on the coating stage is subjected to image recognition by a camera, and alignment is performed to perform position alignment. After the alignment is completed, coating is performed (step 510). The substrate on which the coating is finished is carried out of the coating apparatus (step 511).

At the time point when the substrate finished being coated is carried out, it is determined whether the number of coated substrates has reached a correction period (for example, the number of workpieces or the number of substrates) set in advance (step 512). In the case where the correction period is reached, a correction step to be described below is entered, and in the case where the correction period is not reached, a step 515 is entered.

The correction step includes a positional deviation correction (step 513) and a coating amount correction (step 514). The positional deviation correction adjusts the deviation portion by performing the same operation as in step 502. Then, the coating amount correction is performed by first discharging the coating amount to the weighing apparatus for a predetermined time or the number of shots, and measuring the weight. Then, the measured weight is compared with the reference weight measured in step 506, and when the measured weight exceeds an allowable value, adjustment of the discharge device or the coating device is performed, and the like, and the weight is corrected so as to be the reference weight. As a method of correction, for example, the following two methods are available.

(a) Correction method in dot coating

The number of times of sending the discharge pulse signal and the stop pulse signal is defined as the total pulse number, the number of discharge pulse signals necessary for achieving the coating amount in the total pulse number is defined, and the remaining number is defined as the stop pulse signal, and the number of discharge pulse signals and the number of stop pulse signals are adjusted based on the correction amount calculated by the correction period, thereby correcting the supply amount of the liquid material. Here, it is preferable that a setting table defining settings in which an increasing portion or a decreasing portion of the ejection amount is added is stored in the control section in advance, and the combination of the number of ejection pulses and the number of stop pulses is selected by the setting table to perform correction.

(b) Correction method in linear coating

The method for supplying a liquid material includes the steps of preparing a coating pattern composed of a plurality of continuous coating regions, allocating a plurality of discharge cycles (a set of unit cycles) in which the number of discharge pulses and the number of stop pulses are combined at a predetermined ratio to each of the coating regions, and adjusting the number of discharge pulses and the number of stop pulses included in the coating pattern based on a correction amount calculated by the correction cycle, and/or adjusting the length of at least one coating region and the length of one or two other coating regions continuous to the coating region without changing the discharge amount per unit time in each of the coating regions, thereby correcting the supply amount of the liquid material. It is preferable that the ejection amount is corrected without changing the frequency of sending the ejection pulse and the stop pulse.

After the correction step is completed, or immediately after the substrate is carried out, it is determined whether or not there is an uncoated substrate to be coated next (step 515). If an uncoated substrate is present, the process returns to step 509, and the substrate is carried in again to perform the coating operation. When there is no uncoated substrate, the present coating operation is ended.

The above is a basic series of flows from the preparation stage to the present coating operation. The description here is an example, and the order is not limited to this.

[ preparation of coating Pattern ]

The ejection device of the present embodiment may correspond to any type of coating pattern of dot coating and line coating.

Fig. 14 is a diagram showing an example of a coating pattern by dot coating. In fig. 14, the coating region 141 corresponds to the ejection pulse. The ejection amount in the application region 141 is controlled by setting an ejection pulse, whereby the length of the application region 141 expands and contracts. In addition, by setting the stop pulse, the non-coating region 142 expands and contracts. Here, as a method of calculating the correction amount, any of the following methods may be employed: a method of measuring the weight of the ink ejected for a fixed time and calculating a correction amount from the difference between the measured weight and a proper weight; and a method of measuring a discharge time required until a proper weight is reached and calculating a correction amount from a difference from a previous discharge time.

Fig. 15 is a diagram showing an example of a coating pattern in which a coating region is divided into a plurality of regions and the coating amount is changed for each region in the line coating. In fig. 15, a first ejection period in which ejection pulses and stop pulses are combined at a first ratio and a second ejection period in which ejection pulses and stop pulses are combined at a second ratio are prepared, and one first coating region 151 that ejects in accordance with the first ejection period is connected to second coating regions 152, 152 that eject in accordance with the second ejection period at both ends of the first coating region 151 to form one coating pattern. In the example of fig. 15, the application regions 152 and 152 are associated with the second discharge period, but the present invention is not limited to this, and one of the application regions 152 may be associated with the second discharge period and the other may be associated with the third discharge period. The number of coating regions to be allocated in one ejection cycle may be set to an arbitrary number.

An ejection pulse and a stop pulse are assigned to each coating region. For example, in fig. 15, when the ejection rate in the first coating region 151 is to be made larger than the ejection rate in the second coating region 152, according to the setting example a in table 1, a combination of 3 ejection pulses and 1 stop pulse (ejection 75%) is selected in the second coating region 152, and a combination of 4 ejection pulses and 1 stop pulse (ejection 80%) is set in the first coating region 151.

The number of ejection pulses and the number of stop pulses to be adjusted at the time of correction are the same as those described in (a) above.

The adjustment of the length of each application region means that the length of a plurality of application regions having different application amounts per unit length constituting the application pattern is adjusted. In the case of fig. 15, the coating amount increases if the first coating region 151 is longer, and decreases if it is shorter. In this case, the length of each application region is preferably adjusted without changing the overall length of the application pattern.

The area of the convex portion S1 surrounded by a diagonal line in the graph shown in fig. 15(b) corresponds to the application amount before correction. The area of the convex portion S0 surrounded by oblique lines in the graph shown in fig. 15(c) corresponds to the coating amount after correction. Thus, by lengthening the length of X1 and shortening the length of X2, the amount of coating can be increased. Even when the correction amount varies in the digital correction by the pulse number adjustment, the length of the analog application region can be adjusted to avoid the variation in the correction amount.

(availability in industry)

The present invention can be applied to a type in which the liquid material to be discharged is separated from the nozzle before contacting the coating object. For example, the following is done: a jet type in which a valve body is caused to collide with a valve seat to thereby cause a liquid material to fly and be ejected from the tip of a nozzle; a plunger jet type in which a plunger type plunger is moved and then stopped abruptly, and a liquid material is ejected by flying from a tip of a nozzle in the same manner; and a continuous jet system or an ink jet system on demand.

And, of course, the present invention can be applied to the underfill step of the semiconductor package.

Claims (10)

1. A method for applying a liquid material, which comprises forming a desired application pattern, discharging the liquid material from a nozzle while relatively moving the nozzle and a workpiece, and filling the liquid material in a gap between the substrate and the workpiece mounted on the substrate via 3 or more bumps by using a capillary phenomenon, the method comprising:

an initial parameter setting step of defining the number of times of sending the ejection pulse signal and the stop pulse signal as a total pulse number, defining the number of ejection pulse signals necessary for achieving the coating amount among the total pulse number, and defining the rest as the stop pulse signal;

a correction amount calculation step of measuring an ejection amount from the nozzle and calculating a correction amount of the ejection amount; and

an ejection amount correction step of adjusting the number of ejection pulse signals and the number of stop pulse signals based on the correction amount calculated in the correction amount calculation step;

the ejection rate correction step adjusts the number of ejection pulse signals per unit area of the coating region adjacent to the region having the high degree of bump aggregation to be larger than the number of ejection pulse signals per unit area of the coating region adjacent to the region having the low degree of bump aggregation when the bumps are unevenly arranged.

2. A method for applying a liquid material, which discharges the liquid material from a nozzle while relatively moving the nozzle and a workpiece, and fills a gap between the substrate and the workpiece mounted on the substrate via 3 or more bumps with the liquid material by utilizing a capillary phenomenon, the method comprising:

a coating pattern making step of making a coating pattern composed of a plurality of continuous coating areas;

an ejection cycle allocation step of allocating, to each application region, an ejection cycle in which a plurality of ejection pulse signal numbers and a plurality of stop pulse signal numbers are combined at a predetermined ratio;

a correction amount calculation step of measuring an ejection amount from the nozzle and calculating a correction amount of the ejection amount; and

an ejection amount correction step comprising the steps of: when the bumps are unevenly arranged, adjusting the number of the ejection pulse signals and the number of the stop pulse signals included in the coating pattern so that the supply amount per unit area of the coating region adjacent to the region having the high bump concentration is larger than that of the coating region adjacent to the region having the low bump concentration, based on the correction amount calculated in the correction amount calculation step; and/or adjusting the length of at least the one coating region and the other one or two coating regions continuous with the one coating region without changing the ejection amount per unit time in each coating region.

3. The method for coating a liquid material according to claim 1 or 2,

the ejection rate is corrected without changing the frequency of sending the ejection pulse signal and the stop pulse signal.

4. The method for coating a liquid material according to claim 1 or 2,

when the coating pattern is a coating pattern which does not require the direction change of the nozzle, the coating is performed without changing the relative movement speed of the nozzle and the workpiece.

5. The method for coating a liquid material according to claim 1 or 2,

when the coating pattern is a coating pattern including a coating region requiring nozzle direction switching, the supply amount per unit area in the coating pattern is set so that the liquid material in the coating region requiring no nozzle direction switching becomes larger than that in the coating region requiring nozzle direction switching.

6. A liquid material coating device comprises a spraying device with a nozzle, a driving mechanism for making the spraying device and a workpiece move relatively, a detection device for detecting the shape of the coated liquid material, and a coating device of a control part for controlling the actions; the liquid material application apparatus is characterized in that,

causing a control section to carry out the coating method according to claim 1 or 2.

7. A method for applying a liquid material, which comprises forming a desired application pattern, discharging the liquid material from a nozzle while relatively moving the nozzle and a workpiece, and filling the liquid material in a gap between the substrate and the workpiece mounted on the substrate via 3 or more bumps by using a capillary phenomenon, the method comprising:

an initial parameter setting step of defining intervals between unit periods for performing one ejection;

a correction amount calculation step of measuring an ejection amount from the nozzle and calculating a correction amount of the ejection amount;

and a discharge amount correction step of adjusting the unit cycle interval included in the coating pattern so that the supply amount per unit area of the coating region adjacent to the region having a high degree of bump aggregation is larger than that of the coating region adjacent to the region having a low degree of bump aggregation, based on the correction amount calculated in the correction amount calculation step, when the bumps are unevenly arranged.

8. The method for coating a liquid material according to claim 7,

when the coating pattern is a coating pattern which does not require the direction change of the nozzle, the coating is performed without changing the relative movement speed of the nozzle and the workpiece.

9. The method for coating a liquid material according to claim 7 or 8,

when the coating pattern is a coating pattern including a coating region requiring nozzle direction switching, the supply amount per unit area in the coating pattern is set so that the liquid material in the coating region requiring no nozzle direction switching becomes larger than that in the coating region requiring nozzle direction switching.

10. A liquid material coating device comprises a spraying device with a nozzle, a driving mechanism for making the spraying device and a workpiece move relatively, a detection device for detecting the shape of the coated liquid material, and a coating device of a control part for controlling the actions; the liquid material application apparatus is characterized in that,

causing a control section to perform the coating method according to claim 7 or 8.