TWI480418B - Splashguard for high flow vacuum bubbler vessel - Google Patents

Description

Splasher for high flow vacuum bubbler containers

This patent application is a contiguous patent application of U.S. Patent Application Serial No. 12/407,279, filed on March 19, 2009.

The present invention relates to a splash guard for a high flow vacuum bubbler container.

When vapor transport is employed for CVD, a reservoir typically passes an inert carrier gas through the reservoir or bubbler (i.e., bubbler) to transport the chemical precursor vapor carried within the inert carrier gas. Go to the processing unit. The bubbler typically has a lower tube inlet from which the carrier gas is introduced into the reservoir and under the surface of the liquid chemical precursor, wherein the carrier gas passes upwardly through the liquid chemical precursor to foam The gas carries a chemical precursor as it floats out of the liquid surface as a bubble and exits the reservoir or bubbler through an outlet disposed above the liquid surface of the chemical precursor.

It is undesirable to have the chemical precursor exit the reservoir through the outlet in liquid form, even as small droplets. Homogeneous vapor is preferred as the distribution product for such bubblers. This avoids problems such as corrosion, cleaning, uneven flow, and floating drops, which are suspended during manufacturing and disconnected. Particles may accumulate and form in the outlet during the storage.

Various forms of splash guards for bubblers have been tried in the practice of the art, for example, in US 2008/0143002, US 6,520,218, EP 1329540, US 2004/0013577, EP 0420596, US 5,589,110, US 7,077,388, US 2003/0042630 US 5,776,255 and US 4,450,118. Each of these attempts provides only a spatter function that is less than desired, but as disclosed below, the present invention successfully provides a high level splash guard function while still allowing chemical precursors The high flow rate or flow under high vacuum or high pressure differential conditions, as will be described and illustrated below.

The present invention relates to a reservoir having: a dip tube inlet having an end adjacent to the reservoir base; at least one baffle assembled into a shallow lower open cone at the outlet of the dip tube and the storage Between the outlets of the device, a narrow annular space is provided between the retaining disk and the inner surface of the side wall of the reservoir; a radially inwardly projecting annular deflecting projection is attached to the side wall Adjacent to the baffle, the baffle and deflection projections minimize droplets entering the reservoir outlet; a shoulder having a radially inwardly projecting annular edge on the deflecting projection The innermost edge is axially spaced below; and a liquid level sensor having an end proximate to the base of the reservoir capable of having a liquid level above the end of the liquid level sensor.

The invention also relates to a method of delivering a chemical precursor vapor from a reservoir, the method comprising: passing a carrier gas through a dip tube of the reservoir; Carrying a liquid chemical precursor into the carrier gas; causing the carried chemical precursor and carrier gas to pass through a radially inwardly projecting annular deflection projection on the sidewall and at least one retaining disk, the at least one The retaining disk is in a narrow annular space between the outermost edge of the retaining disk and the inner surface of the reservoir sidewall.

10‧‧‧ bubbler reservoir

11‧‧‧ Lower part of the reservoir

12‧‧‧Bubble side wall

13‧‧‧Storage base

14‧‧‧ dip tube

15‧‧‧Liquid height

16‧‧‧Export

17‧‧‧ Upper part of the reservoir

21‧‧‧ shoulder

22‧‧‧Protruding

23‧‧‧ inner surface

24‧‧‧

24a‧‧‧

24b‧‧‧

24c‧‧‧

24d‧‧‧

26‧‧‧Valves

27a‧‧‧End of dip tube inlet

27b‧‧‧Liquid sensor end

28‧‧‧Liquid sensor

30‧‧‧ valve

32‧‧‧ entrance end

34‧‧‧ innermost edge

36‧‧‧ outermost edge

38‧‧‧Flow path

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side elevational view of one embodiment of the invention shown in partial cross-section.

Figure 2 is a partial side elevational view of one embodiment of the invention shown in cross section.

Figure 3 is a partial side elevational view of a second embodiment of the present invention shown in cross section.

Figure 4 is a partial side elevational view of a third embodiment of the present invention shown in cross section.

Figure 5 is a partial side elevational view of a fourth embodiment of the present invention shown in cross section.

The present invention is a vapor generation bubbler container designed for use in high vacuum or high flow conditions. This design prevents aerosol dripping and transport to the discharge line, both of which result in unstable chemical mass flow.

Semiconductor manufacturers are committed to using high-value chemicals, These chemicals are increasingly difficult to transport for deposition on wafers in vacuum chambers or processing equipment. The bubbler container of the present invention enables liquid chemicals to be transported from the reservoir in vapor form under high vacuum without splashing and forming in the outlet of the reservoir, both of which result in unstable chemical quality Delivery rate. The present invention has a subsurface design that enables a constant saturation of the carrier gas with chemical vapor to be reduced to a very low amount of residual chemical. Also, the present invention prevents aerosol dripping and formation in the reservoir outlet which results in an unstable chemical mass transfer rate, even when the chemical level in the reservoir is high. Previously, reservoirs used for high vacuum use or high flow rates had to be used with only partially filled chemicals (i.e., 50% full). This requires semiconductor manufacturers to change the reservoir more frequently (removing the processing device) and increase the cost of the chemical by increasing the processing cost of the reservoir. The present invention enables the reservoir to be used from a filled liquid chemical level to a very low level and to reduce downtime of the semiconductor processing apparatus. Likewise, because the chemical suspension particles within the outlet can be limited, it is possible to reduce the phenomenon of particle formation that may be caused by the dewatering of the droplets deposited in the outlet and in all of the transfer piping to the processing chamber or processing unit. In this description, it is preferred to have a cylindrical reservoir and the axis of the cylinder is in a vertical plane. Thus, both axial and radial descriptions are relative to the shape and orientation of such reservoirs.

The present invention uses a radially inwardly projecting annular deflecting projection on the inner surface of the side wall of the reservoir in combination with one or more retaining discs on the upper portion of the reservoir, by passing a carrier gas carrying a chemical precursor Swirling in a narrow annular space to the radially innermost edge of the deflecting projection and the retaining discs Outside, the carrier gas with a chemical precursor is indirectly passed to the outlet of the reservoir, wherein the narrow annular space is between the inner diameter of the inner surface of the side wall of the bubbler and the outermost diameter of the spacers Or between the circumference or the perimeter edge. This will be exemplified by reference to preferred embodiments of the invention.

1 shows a bubbler reservoir 10 of the present invention having a cylindrical bubbler sidewall 12, and the inlet end of the dip tube inlet 14 terminates below the level of the liquid chemical precursor (the level is substantially line 15 Illustrative), but above the reservoir base 13.

The splash guard comprises: (1) a retaining disk 24; and (2) a radially inwardly projecting annular deflecting projection 22 on the inner surface 23 of the side wall 12, wherein the baffle 24 has an outermost circumference The perimeter has an edge shape (preferably circular) and is concave downward (eg, a shallow lower open cone); the retaining disk 24 and the deflecting projection 22 cooperate to effect removal of the chemical precursor from the reservoir 10 The tortuous flow path used. The baffle 24 is recessed to further obstruct the direct flow of the chemical precursor to the outlet 16 and collect the returned condensed chemical precursor by dropping the agglomerated droplets back into the stored chemical precursor (not illustrated). The diameter of the retaining disk 24 is slightly smaller than the inner diameter of the cylindrical inner surface 23 of the side wall 12 of the reservoir 10. The space between the outermost edge of the circumferential circumference of the retaining disk 24 and the inner surface 23 of the side wall 12 of the reservoir 10 is sufficient to allow gas to pass through the space with minimal pressure drop, but the space is also narrow enough to allow liquid passage To the finest, the liquid may be ejected from the liquid contents of the bubbler under the effect of high flow rates or significant pressure fluctuations of the carrier gas passing through the dip tube. The reservoir 10 has an upper portion 17 and a lower portion 11 and an exemplary liquid level height 15, which varies according to the degree of filling and the duration of the dispense, but is usually deflected Above the projection 22 and the stop 24 and above the inlet 14 and the end of the level sensor 28 (27a and 27b, respectively).

Figure 2 shows the isolation of the internal structure of the reservoir of this particular embodiment without exemplifying the dip tube 14. A level sensor 28 is shown positioned intermediate the reservoir to monitor the level of liquid chemicals. The end of the level sensor is adjacent to the base 13 of the reservoir 10. The valve 30 controls the push gas or carrier gas to be introduced into the lower portion of the reservoir through the inlet 14, the carrier gas is bubbled through the liquid chemical at the lower portion of the reservoir, and the vapor of the chemical is carried to the carrier gas. In the bubble. When the carrier gas leaves the lower end of the intake dip tube 14, the bubbling action of the carrier gas causes a strong agitation of the liquid chemical. When the valve 26 is opened, the high vacuum on the outlet 16 can also cause intense or vigorous agitation of the liquid chemical. Either of these can cause liquid chemicals to bubble or splash toward the outlet 16. A radially inwardly projecting annular deflecting projection 22 associated with the side wall 12 of the reservoir or bubbler 10 is used to deflect any foaming or splashing liquid chemicals from the outermost edge of the retaining disk 24. In order to protect the inlet end 32 of the outlet 16 from ingesting liquid chemicals, rather than specifying the chemical vapor carried within the carrier gas. The baffle 24 and the deflecting projection 22 form a tortuous flow path 38 for the chemical precursor to exit the reservoir 10.

In a preferred embodiment, the deflecting projection 22 is formed from a portion of the sidewall 12 during milling from the solid member of the stainless steel blank into the reservoir or bubbler 10. The deflecting projection 22 can have a tapered cross-sectional configuration with its innermost edge 34 terminating radially inward of the outermost edge 36 of the retaining disk 24. The deflecting projection may be an annular rim formed entirely around the inner surface 23 of the side wall 12. The combination of the baffle 24 and the deflecting projection 22 forms A tortuous flow path 38 for the carrier gas and the chemical vapor it carries, such a path is extremely difficult for liquid phase chemicals to follow.

Preferably, the retaining disk 24 is axially spaced above the deflecting projection 22 to provide a very narrow flow path for vapor to flow, but the liquid is difficult, that is, the retaining disk 24 and the deflection The projections 22 are close to each other. It is also possible that the baffle 24 is disposed axially spaced below the deflecting projection 22. In addition, the present invention contemplates multiple retaining discs, for example, a retaining disc 24 is disposed axially spaced above the deflecting projection and a retaining disc 24a is axially spaced below the deflecting projection, FIG. 3; 24 and 24b are both disposed axially spaced above the deflecting projection, Figure 5; the second retaining discs 24c and 24d are each axially spaced below the deflecting projection, Figure 4; above and below each of the retaining discs A deflecting projection is provided at intervals; and a plurality of retaining discs and deflecting projections; all of which are preferably adjacent to one another as defined above.

Experience has shown that air bubbles can travel from the end of the intake dip tube 14 along the side wall 12 of the reservoir or bubbler 10, creating the greatest possible splash of liquid fluid at the inner surface 23 adjacent the side wall 12 of the reservoir 10. Thus, in a particular embodiment, the deflecting projection includes a shoulder 21 formed as an annular, radially inwardly projecting annular edge that is axially spaced below the innermost edge 34 of the deflecting projection 22. The deflecting projection 22 is proportional to the shoulder 21 such that the deflecting projection 22 projects radially inwardly beyond the radially inwardly projecting amount of the shoulder 21. This shoulder may be an integral part of one of the entire deflecting projections 22 and can be machined while forming the deflecting projections from a single piece of stainless steel blank or other metal blank. The shoulder 21 has two functions. An acute angle is formed between the shoulder 21 and the inner surface 23, and thus will flow upward along the inner surface The liquid is reintroduced into the interior of the reservoir 10 away from the tortuous path 38 formed by the respective edges of the baffle 24 and the deflecting projection 22. Further, any liquid collected on the deflecting projection 22 is discharged to the shoulder 21 and then dropped back into the liquid chemical contained in the lower portion of the reservoir or bubbler 10.

The shunt plate 24 and the deflecting projection 22 are preferably attached to the upper region 17 of the reservoir (although it is also possible to understand other positioning as long as it is higher than the chemical loaded in the reservoir). The standard upper limit), or the headspace or effluent height, is understood by those skilled in the art, but at least above the liquid level 15.

Although this particular embodiment shows the deflecting projection 22 and the shoulder 21 as being integral with each other and the side wall, it is contemplated that both the deflecting projection 22 and the shoulder 21 may be separate pieces attached to the side wall 12, such as By welding, frictional joints or mechanical fastening (such as bolts, screws and similar fasteners). Even in the form of a separate piece, the deflecting projection 22 and the shoulder 21 may be integrated with each other or may be separate pieces from each other.

The deflecting projection 22, shoulder 21 and retaining disk 24 cooperate to form a tortuous flow path 38 for the chemical to be dispensed through the outlet 16. In some cases, under high vacuum and high flow rates, the liquid tends to form a foam on the liquid surface 15 and into the headspace of the upper region 17 of the reservoir 10. The tortuous flow path 38 formed by the deflecting projection 22, the shoulder 21 and the retaining disk 24 substantially prevents such foam from reaching the outlet 16.

Although stainless steel is mentioned with respect to certain embodiments, it is to be understood that the invention can be applied to different metals, glass and plastics, including mild steel, Monel alloy, Hass. Nickel Hastelloy alloy, nickel alloy, and similar materials known to those skilled in the art.

The present invention provides an extreme minimization of the amount of liquid carried in the form of droplets in the outlet and downstream piping of the reservoir of the CVD processing apparatus connected to the electronic component assembly system. The use of a single or multiple retaining disc in combination with the deflecting projections will provide as much liquid carryover as expected in the outlet 16 of the bubbler.

Although it is shown that the retaining disk is a circular disk with a recess, wherein the diameter of the disk is slightly smaller than the inner diameter of the cylindrical container or the side wall of the bubbler, it can be understood that at the inner side wall of the reservoir Any of the discs of any shape providing only a narrow annulus is within the scope of the present invention. Likewise, any form of deflecting projection having a smooth and radially inwardly projecting edge or having an edge that is somewhat offset from a smooth annular bend is considered part of the present invention.

Although stainless steel is preferred, it is contemplated that any rigid form of inert material can be used for the splash guard. Plastics, metal alloys, powdered metals, fabrics, textiles and ceramics can all be considered.

The container 10 can also be used for reverse product flow wherein the outlet 16 functions as a pressurized gas inlet to form an indenter that acts on the liquid contained in the container 10 and forces the liquid to discharge the dip in liquid phase. The tube 14 carries out liquid delivery from the reservoir using pressurized gas, unlike the vapor delivery described above.

10‧‧‧ bubbler reservoir

11‧‧‧ Lower part of the reservoir

12‧‧‧Bubble side wall

13‧‧‧Storage base

14‧‧‧ dip tube

15‧‧‧Liquid height

16‧‧‧Export

17‧‧‧ Upper part of the reservoir

21‧‧‧ shoulder

22‧‧‧Protruding

23‧‧‧ inner surface

24‧‧‧

26‧‧‧Valves

27a‧‧‧End of dip tube inlet

27b‧‧‧Liquid sensor end

30‧‧‧ valve

28‧‧‧Liquid sensor

32‧‧‧ entrance end

Claims (11)

A reservoir having: a dip tube inlet having an end adjacent the reservoir base; at least one baffle assembled into a shallow lower open cone at an outlet of the dip tube and an outlet of the reservoir Providing a narrow annular space between the retaining disk and the inner surface of the side wall of the reservoir; a radially inwardly projecting annular deflecting projection attached to the side wall adjacent to the block a disc, the baffle and deflection projections capable of minimizing droplets entering the reservoir outlet; a shoulder having a radially inwardly projecting annular edge at the innermost edge of the deflecting projection The lower portion is axially spaced apart; and a liquid level sensor having an end proximate to the base of the reservoir and capable of having a liquid level above the end of the liquid level sensor. A reservoir according to claim 1, wherein the deflecting projection has an innermost edge on a radially inner side of an outermost edge of the at least one retaining plate. A reservoir according to claim 2, wherein the deflecting projection has a shoulder below the innermost edge of the deflecting projection, the shoulder projecting radially inward from the side wall of the inner surface of the reservoir, but The radially inwardly projecting portion of the shoulder is radially shorter than the innermost edge of the deflecting projection. A reservoir according to claim 3, wherein the at least one retaining disk, the deflecting projection and the shoulder are in the upper portion of the reservoir. A reservoir according to claim 1, wherein the deflection projection is a shaft Arranged between the upper and lower retaining discs at intervals. The reservoir of claim 1, wherein the deflecting projections are axially spaced below the second retaining disc. A reservoir according to claim 1 wherein the inlet to the outlet of the reservoir has an elbow configuration that minimizes the amount of liquid entering the outlet of the reservoir. A reservoir according to claim 1 wherein the inlet to the outlet of the reservoir has a T-shaped configuration that minimizes liquid entering the outlet of the reservoir. A reservoir according to claim 1, wherein the reservoir has a cylindrical shape. A cylindrical vapor generating reservoir having: a dip tube inlet capable of delivering a carrier gas into the reservoir; a baffle having a circular and downwardly concave shape at the inlet of the dip tube Between the outlet end and the outlet of the reservoir, and being assembled to provide a narrow annular space between the outermost circumferential perimeter edge of the retaining disk and the inner surface of the reservoir sidewall; a radially inwardly extending An annular deflecting projection attached to the side wall adjacent to the retaining disk, wherein the deflecting projection has an innermost edge on a radially inner side of a peripheral edge of the outermost circumference of the retaining disk, when the carrier gas is worn When the liquid content of the reservoir is foamed to distribute the liquid in the form of vapor from the reservoir, the storage can be made The droplet at the outlet of the reservoir is minimized; a shoulder having a radially inwardly projecting annular edge axially spaced below the innermost edge of the deflecting projection; and a level sensor The end of the reservoir is near the base of the reservoir and can have a liquid level above the end of the liquid level sensor. A liquid dispensing reservoir having: at least one baffle assembled into a shallow lower open cone, between the inlet end of the dip tube outlet and the inlet of the liquid dispensing reservoir, assembled in the block Providing a narrow annular space between the disk and the inner surface of the side wall of the reservoir; a radially inwardly projecting annular deflecting projection attached to the side wall adjacent the retaining disk, wherein the deflecting projection Having an innermost edge on the radially inner side of the outermost edge of the retaining plate to minimize droplets entering the liquid dispensing reservoir inlet; a shoulder having a radially inwardly projecting annular edge And axially spaced below the innermost edge of the deflecting projection; and a liquid level sensor having an end proximate to the base of the reservoir and capable of having a liquid level above the end of the liquid level sensor.