JP2004342716A - Method and apparatus for forming bump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make formable bumps of various shapes while enhancing the productivity. <P>SOLUTION: The method of forming a bump is provided with a step for ejecting a liquid drop of conductive paste, produced by dispersing conductive fine particles becoming a bump material into liquid, onto a substrate by a liquid drop ejecting means, and a step for sintering the ejected liquid drop of conductive paste. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a bump forming method and a bump forming apparatus for forming a bump on a substrate of a semiconductor element such as a diode or an IC (integrated circuit device) or an electrode surface of a printed circuit board.
[0002]
[Prior art]
As a method of forming a bump, a method of using a photoresist film on a base electrode forming surface side of a substrate is known (for example, see Patent Document 1). In such a bump forming method, a photoresist film is formed on a substrate, holes are formed at base electrode positions, a conductive paste is filled therein with a dispenser, a spinner is rotated at a high speed, and the paste on the photoresist film is removed. By shaking off the paste, only the holes are filled with the paste to remain, and prebaked. Further, bumps are formed on the substrate by sintering the conductive paste after removing the photoresist film.
[0003]
As another bump forming method, a method using screen printing is known (for example, see Patent Document 2). In such a bump forming method, a mask on which a bump forming pattern is formed is positioned on a base electrode forming surface side of a substrate, a conductive paste is printed through the mask, and after the mask is removed, sintering is performed to form a bump on the base electrode. The formation of.
[0004]
[Patent Document 1]
JP-A-9-64047 (FIG. 1-5)
[0005]
[Patent Document 2]
JP-A-6-204229 (FIG. 1)
[0006]
[Problems to be solved by the invention]
However, in the case of the conventional example described in Patent Literature 1, since the paste is applied to the photoresist film other than the holes due to the use of the dispenser, it is troublesome to remove the paste other than the holes by using a spinner. There was a problem that it took.
[0007]
Further, in the case of the conventional example described in Patent Document 2, since a patterned mask is required for forming the bumps, the shape of the bumps is restricted in advance, and it is not easy to respond to changes and improvements. There was an inconvenience. Further, since a mask is required, there is also a problem that the cost is increased in the small-scale production.
[0008]
An object of the present invention is to improve productivity by speeding up pump formation.
Still another object of the present invention is to easily form bumps of various shapes.
Still another object is to reduce costs in the case of small-scale production.
[0009]
[Means for Solving the Problems]
The invention according to claim 1 is a discharge step of discharging droplets of a conductive paste formed by dispersing conductive fine particles serving as bump materials in a liquid on a substrate by a droplet discharging means, And a sintering step of sintering the droplets.
[0010]
In the above configuration, in the discharging step, the bumps are formed by sequentially discharging droplets of the conductive paste on the substrate and stacking a plurality of droplets according to a predetermined shape.
In the above configuration, in the discharging step, droplets of the conductive paste are discharged onto the substrate, and further, sintering is performed in the sintering step to form bumps. The sintering in the sintering step may be performed after the bumps are stacked according to the overall shape, or may be performed each time a single discharge is performed. Further, the sintering of the droplets may be performed immediately after the discharge and before hitting the substrate, or may be performed on the substrate. Sintering may be performed intermittently or continuously.
The “substrate” includes a substrate of a semiconductor element such as a diode and an IC, and a printed circuit board. In addition, “on the substrate” may be on the substrate, and includes on a base electrode provided on the substrate. Except where specifically described, the same applies to the entire description of the present specification (including inventions described in other claims).
[0011]
A second aspect of the present invention has the same configuration as the first aspect of the present invention, and adopts a configuration in which a sintering step is performed for each of one or more discharge steps.
In the above configuration, the same operation as that of the first aspect of the invention is performed, and sintering is performed every time the conductive paste droplet is discharged or every time a plurality of discharges are made.
[0012]
The invention according to claim 3 has the same configuration as the invention according to claim 1 or 2, and the fine particles are gold, silver, copper, platinum, palladium, tungsten, nickel, tantalum, bismuth, lead, indium, tin. , Zinc, titanium, or aluminum, or an oxide thereof, or an alloy of any two or more of these metals.
With the above configuration, a bump containing any one of the above-described materials is formed.
[0013]
The invention according to claim 4 has the same configuration as the invention according to claim 1, 2 or 3, and in the sintering step, the conductive paste liquid is irradiated by irradiation of at least one of infrared rays, laser light, and electron beam. It employs a configuration that heats the drops.
With the above configuration, in the sintering step, the droplets of the conductive paste are sintered by receiving at least one of infrared, laser, and electron beams on the discharge path or on the substrate.
[0014]
A fifth aspect of the present invention has a configuration similar to that of the first, second, third, or fourth aspect of the invention, and has a configuration in which the particle diameter of the fine particles is 100 nm or less.
In the above configuration, the same operation as that of the first, second, third, or fourth aspect of the invention is performed, and the discharge is performed in units of ultrafine particles of 100 nm or less.
The “particle size of fine particles” refers to the number average value of the diameter of a circumscribed circle obtained by measuring 100 arbitrary fine particle samples by electron microscopy. Except where specifically described, the same applies to the entire description of the present specification (including inventions described in other claims).
[0015]
The invention according to claim 6 has the same configuration as the invention according to claim 1, 2, 3, 4, or 5, and has a configuration in which the discharging step is performed a plurality of times and the droplets are stacked to form a bump. I am taking it.
In the above configuration, in the discharging step, the conductive paste droplets are discharged onto the substrate a plurality of times, and the plurality of droplets are stacked according to a predetermined shape to form a bump.
[0016]
The invention described in claim 7 has the same configuration as the invention described in any one of claims 1 to 6, and adopts a configuration in which the sintering step is performed in parallel with the discharge step.
“Performing the sintering step in parallel with the discharging step” means that the discharging step and the sintering step overlap with each other in terms of time. That is, sintering to droplets may be started from the ejection of the droplets to the landing on the substrate, or the ejection may be performed to the substrate in a state where the processing required for sintering has already been started. good. Except where specifically described, the same applies to the entire description of the present specification (including inventions described in other claims).
[0017]
The invention described in claim 8 has the same configuration as the invention described in any one of claims 1 to 6, and adopts a configuration in which the sintering step is performed immediately after the discharge step.
In the above configuration, sintering starts immediately after the ejection of the droplet.
[0018]
According to a ninth aspect of the present invention, there is provided a resist film forming step of forming a resist film on a substrate, wherein the resist film has an opening similar to that of any one of the first to eighth aspects. And forming an opening. The discharging step discharges droplets to the opening.
[0019]
In the above configuration, the same operation as the invention according to any one of claims 1 to 8 is performed, a photoresist film is previously formed on the substrate, and an opening is formed at the bump formation position. Is done. Then, droplets are ejected toward the opening, and a bump is formed in accordance with the opening. After the sintering of the droplets, the photoresist film is removed.
[0020]
According to a tenth aspect of the present invention, a substrate holding means for holding a substrate, and a droplet of a conductive paste formed by dispersing conductive fine particles serving as a bump material in a liquid are directed toward the substrate on the substrate holding means. A structure comprising: a droplet discharging means for discharging; a positioning means for positioning a discharging position of the droplet discharging means with respect to the substrate on the substrate holding means; and a sintering means for sintering the discharged droplets of the conductive paste. Has been adopted.
[0021]
In the above configuration, droplets of the conductive paste are ejected from the droplet ejection unit whose ejection position is positioned by the positioning unit at a predetermined position on the substrate held by the substrate holding unit. Such discharge is performed by sequentially changing the discharge position by the positioning means, and is stacked so as to form a pump having a predetermined shape.
The sintering by the sintering means may be performed after the bumps are stacked according to the overall shape, or may be performed once or every time a predetermined number of ejections are performed. Further, the sintering of the droplets may be performed immediately after the discharge and before hitting the substrate, or may be performed on the substrate. The sintering may be performed intermittently or continuously while the droplets are being discharged.
[0022]
An eleventh aspect of the present invention has the same configuration as that of the tenth aspect of the present invention, and controls the sintering means so as to sinter the droplets each time the droplet is ejected one or more times. And a control means for performing the control.
In the above configuration, the same operation as that of the tenth aspect of the invention is performed, and sintering is performed every time the conductive paste droplet is discharged or every time a plurality of discharges are made.
[0023]
A twelfth aspect of the present invention has the same configuration as that of the tenth or eleventh aspect, and the fine particles are made of gold, silver, copper, platinum, palladium, tungsten, nickel, tantalum, bismuth, lead, indium, and tin. , Zinc, titanium, or aluminum, or an oxide thereof, or an alloy of any two or more of these metals.
With the above configuration, a bump containing any one of the above-described materials is formed.
[0024]
A thirteenth aspect of the present invention has the same configuration as the tenth, eleventh, or twelfth aspect, and the sintering means irradiates at least one of infrared rays, laser light, and an electron beam. Has been adopted.
With the above configuration, the sintering unit sinters the droplets of the conductive paste by receiving any one of infrared rays, laser light, and electron beams on the discharge path or on the substrate.
[0025]
A fourteenth aspect of the present invention has a configuration similar to that of the tenth, eleventh, twelfth or thirteenth aspect, and has a configuration in which the particle diameter of the fine particles is 100 nm or less.
With the above configuration, the same operation as that of the invention according to claim 10, 11, 12, or 13 is performed, and the discharge is performed in units of ultrafine particles of 100 [nm] or less.
[0026]
The invention according to claim 15 has the same configuration as the invention according to claim 10, 11, 12, 13, or 14, and performs droplet discharge so that droplets are discharged a plurality of times to form a bump by stacking droplets. The means of controlling the means is adopted.
In the above configuration, the bump is formed by discharging the conductive paste droplets onto the substrate a plurality of times by the discharging means and stacking the plurality of droplets according to a predetermined shape.
[0027]
The invention according to claim 16 has the same configuration as the invention according to any one of claims 10 to 15, and sintering of the droplet by the sintering unit is performed in parallel with the ejection by the droplet ejection unit. The sintering means is controlled so as to be performed.
The expression “performed in parallel with the discharge” means that the discharge by the droplet discharge means and the sintering by the sintering means overlap with each other in terms of time. That is, sintering to droplets may be started from the ejection of the droplets to the landing on the substrate, or the ejection may be performed to the substrate in a state where the processing required for sintering has already been started. good. Except where specifically described, the same applies to the entire description of the present specification (including inventions described in other claims).
[0028]
The invention according to claim 17 has the same configuration as the invention according to any one of claims 10 to 15, and sintering of the droplet by the sintering unit is performed immediately after ejection by the droplet ejection unit. The sintering means is controlled so as to be performed.
In the above configuration, sintering starts immediately after the ejection of the droplet.
[0029]
The invention according to claim 18 has the same configuration as the invention according to any one of claims 10 to 17, and the positioning means discharges droplets to the opening of the resist film formed on the substrate. In such a case, the position of the droplet discharge means is determined with respect to the substrate.
[0030]
In the above configuration, the same operation as the invention according to any one of claims 10 to 17 is performed, a photoresist film is previously formed on the substrate, and an opening is formed at a bump formation position. Is done. Then, droplets are ejected toward the opening, and a bump is formed in accordance with the opening. After the sintering of the droplets, the photoresist film is removed.
[0031]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram showing a schematic overall configuration of a bump forming apparatus 10 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of an ejection head described later.
[0032]
(Overall configuration of bump forming apparatus)
The bump forming apparatus 10 includes a substrate holding unit 20 for holding a substrate K on which a base electrode (not shown) is provided, and conductive fine particles serving as a bump material are applied to the substrate K on the substrate holding unit 20 by a liquid. A discharge head 30 serving as a droplet discharge means for discharging droplets of conductive paste dispersed therein, and an XY stage serving as a positioning means for positioning a discharge position of the discharge head 30 with respect to the substrate on the substrate holding means 20 40, a laser emitting means 50 as a sintering means for sintering the discharged conductive paste droplets, and a control means (not shown) for controlling the operation of each of the above means.
[0033]
(Substrate holding means and XY stage)
The substrate holding means 20 includes a substrate stage 21 having a horizontal mounting surface for the substrate K thereon and a holding means 22 capable of switching between holding and releasing the substrate K on the substrate stage 21.
The substrate holding means 20 is provided above the XY stage 40. The XY stage 40 can move and position the substrate holding means 20 in an X-axis direction and a Y-axis direction orthogonal to each other on a horizontal plane. The XY stage 40 positions the substrate K at a predetermined bump forming operation start position with respect to the discharge head 30, and at the time of the bump forming operation, droplets of the conductive paste sequentially discharged from the discharge head 30 form a predetermined position on the base electrode. The substrate K is driven via the substrate holding means 20 so as to hit the position.
[0034]
(Ejection head)
As shown in FIG. 2, the discharge head 30 includes a substrate 31 supported by a support frame of a device (not shown), a piezoelectric element 32 provided on the substrate 31, and a piezoelectric element 32, a lead wire 33, and an electrode 34. And a flow path forming member 36 that forms a storage section 36a for the conductive paste and a flow path 36b derived from the storage section 36a.
[0035]
The flow path forming member 36 forms a plurality of storage portions 36a of the conductive paste and the flow paths 36b arranged in a horizontal direction (the horizontal direction in FIG. 1). Each storage section 36a is provided with a supply port 36c from a supply section of a conductive paste (not shown). Each flow path 36b is led out of the storage section 36a and is connected to a nozzle 37 provided at the lower end of the discharge head 30 for discharging droplets of the conductive paste.
[0036]
Further, the above-described piezoelectric element 32 is disposed in the storage section 36a and the flow path 36b so as to correspond to each of the storage section 36a and the flow path 36b, and a pulse voltage is applied to the piezoelectric element 32. Then, the piezoelectric element 32 expands in its thickness direction (the left-right direction in FIG. 2) and presses the conductive paste in the storage portion 36a and the flow path 36b, and a droplet having a predetermined particle size is discharged from the nozzle portion 37. It has become. The conductive paste is supplied to each storage section 36a at a predetermined supply pressure, and the supply pressure prevents the conductive paste from flowing backward from the storage section 36a to the conductive paste supply section side.
The nozzle portions 37 arranged in the horizontal direction are provided at intervals equal to a general standard value of the arrangement pitch of the base electrodes provided on the substrate K, so that a plurality of base electrodes can be simultaneously bumped. It is possible to perform the formation. Needless to say, the interval between the nozzle portions 37 may be set to be equal to the arrangement pitch of the base electrodes of various substrates.
[0037]
The piezoelectric element drive circuit 35 applies a pulse voltage of a specified potential to each piezoelectric element 32 as described above. The piezoelectric element driving circuit 35 is controlled by an operation control unit of the bump forming apparatus 10 (not shown), for example, to discharge conductive paste droplets only from a nozzle 37 selected from a plurality of nozzles 37, It is possible to perform continuous ejection at predetermined time intervals set for each nozzle unit 37.
[0038]
(Laser emitting means)
The laser emitting means 50 is composed of a laser light source and its optical system, is supported by a device frame (not shown) above the substrate holding means 20, and irradiates the upper surface of the substrate K on which the substrate holding means 20 is held with laser light. . Then, the droplets of the conductive paste discharged to the substrate K by the irradiation of the laser beam are heated and sintered. Note that the laser beam irradiation may be continuously performed during the bump forming operation, or may be performed intermittently only when the conductive paste is discharged.
[0039]
(Conductive paste)
As the conductive paste, a conductive paste obtained by dispersing fine particles in a liquid containing a thermosetting resin and an organic solvent is used. The fine particles may be a metal made of any one of gold, silver, copper, platinum, palladium, tungsten, nickel, tantalum, bismuth, lead, indium, tin, zinc, titanium or aluminum, or an oxide thereof, or each metal Those containing an alloy composed of any two or more of these are used. In particular, when "Nanopaste (NP series)" (trademark: Harima Chemicals, Inc.) is used as a conductive paste, it is suitable for forming finer bumps.
Further, the fine particles contained in the conductive paste are desirably 100 [nm] or less, whereby fine bumps can be formed.
[0040]
(Description of operation of the embodiment)
The operation of the bump forming apparatus 10 will be described with reference to FIGS. FIG. 3 is an operation explanatory view showing an intermediate process of the bump formation, and the two-dot chain line in the figure shows the shape of the bump B to be formed.
The operation of each unit described below is controlled by the control unit. Although not shown in detail, such control means is used as a CPU for performing various arithmetic processes, a ROM in which various programs for various processes for performing operation control described later are stored and stored, and a work memory in various processes. And a RAM to be used. The substrate holding means 20, the ejection head 30, the XY stage 40, and the laser emitting means 50 are connected to the control means via a system bus and a driving circuit.
[0041]
In the forming operation of the bump B, first, when the substrate K is mounted on the substrate holding means 20, the plurality of nozzle portions 37 of the discharge head 30 individually discharge toward the respective base electrodes of the substrate K. Then, the substrate K is positioned at the initial position by the XY stage 40.
[0042]
Then, in a state where the substrate K is irradiated with the laser beam by the laser emitting means 50 (sintering step), droplets of the conductive paste are ejected from each nozzle portion 37 (ejection step). The discharged droplet hits a base electrode of the substrate K and is simultaneously irradiated with a laser beam and sintered by heating. At this time, the organic solvent that maintains the liquid state contained in the droplets of the conductive paste evaporates, the thermosetting resin is cured, and the metal particles are sintered and fixed to the hit position.
[0043]
The droplets of the conductive paste are sufficiently smaller in diameter than the bumps B, and the bumps are formed by being repeatedly ejected and stacked up. That is, as shown in FIG. 3, when one layer is formed at the height of one droplet, a new layer is formed on top of that layer, and this is repeated to form a predetermined shape. A bump B is formed.
[0044]
(Effects of the embodiment)
As described above, since the bump forming apparatus 10 forms the bumps in the step of discharging the droplets of the conductive paste and the step of sintering the same, the operation itself in each step is simple, and the photoresist or the mask is used. This eliminates the need for pre-preparation, etc., thereby facilitating and speeding up the work and improving productivity. Further, chemicals such as photoresist are not required for the bump forming operation, and the generation of waste after the operation is reduced, so that the influence on the surrounding environment can be sufficiently reduced.
Further, in the bump forming apparatus 10, since the bumps can be formed by discharging the droplets of the conductive paste and stacking a plurality of layers, by changing the shape of each layer, for example, as shown in FIG. A) It is possible to form bumps B of various shapes as shown in FIGS.
In this case, sintering can be performed for each droplet, for each of a plurality of droplets, for each layer, or for each of a plurality of layers according to the characteristics of the conductive paste.
[0045]
(Other)
The sintering unit is not limited to the laser beam emitting unit described above, and may be configured to perform heating by irradiating an electron beam or infrared rays. By sintering using laser light emitting means and means for irradiating electron beam or infrared rays, it is possible to locally heat, so that even if bumps are formed on a substrate with heat-sensitive parts, parts can be damaged. It can be suppressed, or deformation of the substrate due to heat can be suppressed. Further, a configuration may be adopted in which a heat stage for heating the substrate from the back side is provided. Further, various light irradiation means and a heat stage may be used in combination.
[0046]
Further, the droplet discharging means is not limited to the piezo type discharging head, but may have another configuration capable of discharging the conductive paste as droplets. For example, various liquid ink discharge head technologies used in an image forming apparatus, for example, a thermal discharge head that discharges by generating a bubble of liquid by rapidly heating in a flow path, or a droplet by electrostatic suction force A discharge head of an electrostatic suction type that discharges ink may be applied.
[0047]
Further, the irradiation position of the laser beam from the laser emitting means 50 is not limited to the case of irradiating the upper surface of the substrate K. good. For example, as shown in FIG. 5, the direction may be set so as to irradiate an area in the middle of the passage of the discharged droplet.
The sintering may be performed after the droplet lands on the substrate K side, or may be performed by discharging while the substrate K is heated in advance and sintering.
[0048]
Further, the positioning means is not limited to the XY stage for moving the substrate K, but a means for moving and positioning the ejection head 20 may be used. Further, it may be constituted by a means for moving and positioning the substrate only in a direction along a certain straight line, and a means for moving and positioning the ejection head along another linear direction intersecting the same.
[0049]
In the above embodiment, the substrate K is positioned in the horizontal plane (the X-axis direction and the Y-axis direction). However, the positioning may be adjusted in the vertical direction. The ejection head 30 may be positioned vertically.
[0050]
Further, in the above embodiment, a resist film is formed in advance on the substrate K (resist film forming step), and an opening is provided at a bump formation target position (opening forming step). The control unit may control the XY stage 40 and the ejection head 30 so that the substrate K is placed on the surface and the droplet is ejected toward the opening. In this case, position coordinate data indicating the position of the opening is input to the control means in advance, and the positioning operation of the XY stage 40 is controlled in accordance with the data, or the opening is determined from the image captured by the optical element or the imaging means. Recognition / identification may be performed to control the positioning operation of the XY stage 40.
[0051]
【The invention's effect】
According to the present invention, since bumps are formed by discharging and sintering conductive paste droplets by droplet discharging means, bumps can be formed easily and quickly, and the productivity can be improved. It becomes possible. Further, since a patterned mask is not required, cost can be reduced even in small-quantity production. Further, by adjusting the relative positional relationship between the droplet discharging means and the substrate, it is possible to easily form bumps of various shapes. Furthermore, if bumps are formed by stacking droplets, bumps of various shapes can be formed.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a schematic overall configuration of a bump forming apparatus according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the ejection head disclosed in FIG.
FIG. 3 is an operation explanatory view showing a process in the middle of bump formation.
FIGS. 4A to 4C are explanatory views showing examples of bumps having various shapes.
FIG. 5 is an explanatory view showing another example of the irradiation position of the laser emitting means.
[Explanation of symbols]
Reference Signs List 10 bump forming apparatus 20 substrate holding means 30 discharge head (droplet discharge means)
40 XY stage (positioning means)
50 Laser emitting means (sintering means)
B bump K board

Claims (18)

A discharging step of discharging droplets of a conductive paste, which is obtained by dispersing conductive fine particles serving as bump materials in a liquid, on a substrate by a droplet discharging means;
A sintering step of sintering the discharged droplets of the conductive paste. 2. The bump forming method according to claim 1, wherein the sintering step is performed for each of one or more discharge steps. The fine particles may be made of any one of gold, silver, copper, platinum, palladium, tungsten, nickel, tantalum, bismuth, lead, indium, tin, zinc, titanium or aluminum, or an oxide thereof, or a metal of the above metals. The bump forming method according to claim 1, further comprising an alloy composed of any two or more of the above. 4. The bump forming method according to claim 1, wherein in the sintering step, droplets of the conductive paste are heated by irradiation of at least one of infrared rays, laser light, and electron beams. 5. The bump forming method according to claim 1, wherein said fine particles have a particle diameter of 100 [nm] or less. 6. The bump forming method according to claim 1, wherein the discharging step is performed a plurality of times, and the droplets are stacked to form a bump. The bump forming method according to claim 1, wherein the sintering step is performed in parallel with the discharging step. The bump forming method according to any one of claims 1 to 6, wherein the sintering step is performed immediately after the discharging step. A resist film forming step of forming a resist film on the substrate,
An opening forming step of forming an opening in the resist film;
9. The bump forming method according to claim 1, wherein, in the discharging step, the droplet is discharged to the opening. 10. Substrate holding means for holding a substrate,
Droplet discharging means for discharging droplets of a conductive paste formed by dispersing conductive fine particles serving as bump materials in a liquid toward the substrate on the substrate holding means,
Positioning means for positioning the position of the droplet discharge means with respect to the substrate on the substrate holding means,
Sintering means for sintering the discharged droplets of the conductive paste. 11. The bump forming method according to claim 10, further comprising a control unit for controlling the sintering unit so as to sinter the droplet at each time of one or a plurality of ejections by the droplet ejection unit. apparatus. The fine particles may be made of any one of gold, silver, copper, platinum, palladium, tungsten, nickel, tantalum, bismuth, lead, indium, tin, zinc, titanium or aluminum, or an oxide thereof, or a metal of the above metals. The bump forming apparatus according to claim 10, further comprising an alloy composed of any two or more of the above. 13. The bump forming apparatus according to claim 10, wherein the sintering unit irradiates at least one of infrared light, laser light, and electron beam. 14. The bump forming apparatus according to claim 10, wherein the fine particles have a particle diameter of 100 [nm] or less. 15. The bump forming apparatus according to claim 10, wherein the discharging is performed a plurality of times, and the droplet discharging unit is controlled so that the droplets are stacked to form a bump. 16. The sintering unit is controlled such that sintering of the droplet by the sintering unit is performed in parallel with ejection by the droplet ejection unit. Item 4. The bump forming apparatus according to Item 1. 16. The sintering unit is controlled such that sintering of the droplet by the sintering unit is performed immediately after discharge by the droplet discharge unit. Item 4. The bump forming apparatus according to Item 1. 18. The method according to claim 10, wherein the positioning unit performs positioning of the droplet discharging unit with respect to the substrate such that the droplet is discharged to an opening of a resist film formed on the substrate. The bump forming apparatus according to claim 1.

Images