WO2002049095A1

WO2002049095A1 - Wafer carrier

Info

Publication number: WO2002049095A1
Application number: PCT/JP2000/008767
Authority: WO
Inventors: Toshio Ishikawa
Original assignee: Dainichi Shoji Kabushiki Kaisha
Priority date: 2000-12-12
Filing date: 2000-12-12
Publication date: 2002-06-20

Abstract

A plurality of wafers (23) are held and spaced parallel and can be loaded/unloaded through the front of a carrier. Protrusions (49) having arcuate inner peripheral parts (47) are provided to teeth (30) which are formed on the inner wall of a wafer carrier (21) and which hold the peripheral part of each wafer from the left and right sides. Thereby, wafers are symmetrically held on the back and front sides. As a consequence, when thin wafers are accommodated, downward warp of the wafers is reduced and the work of loading/unloading of a wafer is easy. Each protrusion has a discrete shape in vertical cross section to prevent interference with a wafer being loading/unloading. The size F of the flat part of each valley part of the waving shape in the vertical cross section of the teeth is large so as to increase the size of the pickup area for picking up a wafer.

Description

Specification

Wafer-to-carrier

Technical field

The present invention relates to a structure of a wafer carrier for holding, carrying, and transporting a plurality of wafers such as silicon wafers so as not to contact each other. Technology background

Wafers such as silicon wafers are stored in a carrier called a wafer carrier (or wafer set) and transported and loaded into various semiconductor manufacturing equipment. Main items such as the number of wafers per wafer, shape, dimensions, etc.

Standardized to the SEM I standard (SEMI (Semi conduct or Equipment and Materia l Int erna nal) standard E l. 7. 94. 200 mm ø carrier etc.).

As shown in FIGS. 6 and 7, such holding of the wafer 13 by the wafer carrier 11 is performed between the respective teeth 7 formed in alignment with the inner peripheral wall 5 of the wafer carrier 11. This is done by pocket 9 (Figure 8), which is configured. The aligned teeth 7 have a substantially corrugated cross section cut in the alignment direction (FIG. 8), and have a substantially U-shape when viewed from the alignment direction (plan view 7). Thus, the edge of each wafer 3 is held in an arc shape. Each wafer 13 is held horizontally or vertically in a state of being parallel to each other. In the horizontal state, each wafer 13 is placed in front of the pocket 9 from the near side (from the substantially U-shaped opening side). ) Pushed into the back and stored, and taken out from the back to the front.

Further, for example, the wafer carrier 11 for storing the wafer 3 having a diameter of 200 mm has a storage number of 25, and the interval L between the pockets 9 for storing is 6.35 mm. Silicon wafers are constantly increasing in diameter in order to produce large quantities of semiconductor elements called chips at once and reduce costs. In addition, the miniaturization of electronic devices, such as recent mobile phones, telephones, personal computers, and digital cameras, has been progressing, and accordingly, semiconductor devices have always required higher integration, lower power consumption, higher speed, and smaller size. Is required. In particular, the miniaturization of semiconductor elements has led to the formation of semiconductor circuit sandwich patterns and miniaturization of packages.

Generally, the miniaturization of a semiconductor device package is called CSP (chip size package). Conventionally, a semiconductor element is bonded to a lead frame, the bonding pad is connected to the lead frame with a wire (wire-to-bonding), the element is sealed with resin, the lead frame is cut, and the terminal is bent. , Package. On the other hand, for example, what is called wafer level C, S, or P, first performs a grinding process (back grind) to cut the back surface of the wafer as thinly as possible, and then, before cutting each chip, Process for forming insulators, buffers, conductive areas, etc. Therefore, a wafer having a smaller thickness than before must be handled by the conventional carrier. However, originally, the conventional wafer carrier 11 is used in the first half of a plurality of processes constituting a semiconductor manufacturing process, that is, a process until a plurality of semiconductor circuits are formed on the surface of the wafer 13. It is standardized for the purpose.

Therefore, in order to perform the wafer levels C, S, and P, a grinding (back-grinding) step of shaving the back surface of the wafer 13 after the completion of the preceding step, and further, before cutting into chips, It is not intended to be used for a thinned wafer 13 in a forming process for forming an insulator, a buffer, a conductive region, and the like on a chip surface.

Therefore, as described below, there is a problem that the distance L between the wafers 13 is too small when the wafer 13 is taken in and out.

That is, as shown in FIG. 8, a circular thin plate-shaped tool called an end effector 11 is used to support the wafer 13 in and out. For example, at the time of unloading, it is sufficient that the distance L between the held wafers 3 is larger than the thickness T (for example, 1.8 to 2.0 mm) of the end effector 11. is not. Further, it must be larger than the sum of the deflection (△ 1, Δ2) of the wafer 13 due to its own weight and the size of the area size P for the pickup for lifting the wafer 13. In the radius, while the wafer 13 was held horizontally in the pocket 9, the wafer 1 was supported by the downward warp Δ1 in the center portion in the left-right direction of the wafer when viewed from the loading / unloading direction, and the end effect 11-1. There is a sag Δ2 at both ends in the state.

In other words, in order to perform the removal, the end effector 11 is inserted between the wafers 13 and is brought into contact with the lower surface of the wafer 13 to raise the warp Δ1 to eliminate the warp △ 1, and further reduce the warp △ 2 The contact with the tooth 7 disappears by lifting up by the dimension of, and it is necessary to be lifted up by P in order to leave the tooth 7 sufficiently. Therefore, the spacing L dimension of wafer 3 is

L> △ 1 + Δ 2 + P

Need to be Conventionally, the interval between the teeth 7, the interval between the pockets 9, and the interval L between the held wafers 13 are, for example, 6.35 mm. However, when the conventional wafer carrier 11 is used for a thinned wafer 13 and used, for example, in the forming process for forming the insulator, the buffer, and the conductive region, the wafer 3 becomes thin. As a result, the downward warpage Δ1 when held horizontally in the pocket 9 is increased as compared with the conventional thick wafer. Although it differs to some extent under various conditions, under certain conditions, the thickness of a wafer and an example of this warpage 1 are as follows.

Thickness Warp Δ 1

7 5 0 Λί ΐη 0.2 mm

This Δ1 was measured in the left-right direction and the center in the front-rear direction.

Conventionally, the clearance L between the pockets 9 was increased to eliminate the above-mentioned problems in holding the thinned wafer 3 on the wafer carrier 1. The distance between the held wafers 13 was increased. Conventional technology

(1) However, if the distance L between the wafers 3 is widened, the number of wafers 3 stored in one wafer carrier 1 is reduced. In addition, since the interval L between the wafers 3 was changed, it was necessary to adjust the control of a robot that puts the wafer 13 in and out. Furthermore, if the distance L between the wafers 13 is increased to maintain the number of stored wafers, the outer dimensions of the wafer carrier 11 are changed, and the control of the robot needs to be adjusted.

(2) Further, when the downward warpage 1 of the wafer 13 was increased, the bending stress on the surface of the wafer 13 was increased, which had a physical and mechanical adverse effect on the crystal on the surface. The adverse effect was that the wafer 13 held inside the wafer carrier 1 when the wafer carrier 1 was transferred vibrated up and down, and was further increased, and in severe cases, was damaged.

(3) Further, the contact holding of the wafer 13 by the pocket is performed only on the back side of the center of the wafer 3, and the front side is not contacted and held for taking in and out. For this reason, the warpage Δ 1 is further increased on the near side. Therefore, the problem of a decrease in the number of sheets to be stored and an adverse effect on crystals has been increasing.

(4) In the cross section of the teeth 7 in the alignment direction, the inner wall surface of the pocket 9 formed between the teeth 7 is flat and is called a pocket flat nest 13. The tongue 13 is small (for example, 1.8 to 2.2 mm), so that the area size P for the big-up is also small (for example, 2.0 to 2.4 mm).

Here, the area dimension P for pick-up is larger than the pocket flatness 13 described above because the tooth 7 has a substantially corrugated cross section cut in the alignment direction and is held at the tip of the peak. It is for doing. -And if there is a large value of the sag Δ2, both ends of the wafer 13 will be held diagonally in the pockets 9 and therefore the pocket dimensions at the tip of this chevron will not be fully used, and more and more Area size P for big-up becomes smaller Met.

In order to easily pick up the wafer 3 that becomes thinner and Δ2 becomes larger, apart from the problem of the distance L between the wafers 3, this problem must be solved. (5) In order to reduce the sag Δ2, it is desirable to use a wide end effector 11, but in this case, the portion on the front side of the teeth 7 becomes small so as not to interfere with the end effector 11. However, it is not possible to support the wafer 3 at the front side and reduce the warpage Δ1.

The present invention has been made in order to solve the above-described problems, and by storing a wafer having a small thickness, by reducing the downward warpage (SAG) Δ1 of the wafer. It is an object of the present invention to enable a robot or a human to easily and stably transfer a wafer. Disclosure of the invention

The invention for achieving the above object is the following invention.

A first invention is a wafer carrier having the following configuration for storing and transporting a wafer.

a. A plurality of wafers are provided on the inner peripheral wall of the wafer-one carrier so as to hold a plurality of the wafers in parallel and separate from each other so that they can be taken in and out from the near side, and hold the peripheral edge of each wafer-side from the left and right. And the teeth

b. A projection formed on each of the teeth and having an arc-shaped inner peripheral edge to hold the left and right peripheral edges of the respective wafers 1 not only on the inner side but also on the nearer side than the center of the wafer 1. ,

c is a vertical cross-sectional shape of the teeth group, has a continuous waveform near the inner peripheral wall of the wafer one carrier, in the protruding portion, so as not to interfere with the end effector one or wafer one that is put in and out. A longitudinal cross-sectional shape with an intermittent shape. A second invention is the wafer carrier according to claim 1, wherein the arc-shaped inner peripheral edge portion is symmetrical on a back side and a near side. A third invention is the wafer carrier according to claim 2, wherein the interval between the tips of the protrusions formed on the left and right is not more than 90 mm and not less than 15 mm. A fourth invention is a wafer carrier having the following configuration for storing and transporting a wafer.

b. The vertical cross-sectional shape of the teeth group, in the vicinity of the inner peripheral wall of the wafer and the carrier, has a continuous waveform, and the valley of the waveform has a flat portion having a dimension of 4 mm or more, . Vertical cross-sectional shape within 5 mm. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of a wafer carrier according to one embodiment of the present invention. FIG. 2 is a vertical cross-sectional view showing a state in which the wafer / carrier of FIG. 1 is divided into front and rear portions. In Fig. 3, (A) is a horizontal sectional view of Fig. 1, (B) is a partially enlarged view of a 0-B section of (A), and (C) is a partially enlarged view of a 0-C section of (A). It is.

FIG. 4 is a plan view of an end effector used for taking a wafer in and out of the wafer carrier of FIG.

FIG. 5 is a horizontal sectional view showing another embodiment.

FIG. 6 is a front view of a conventional wafer-one carrier.

7A is a horizontal sectional view of FIG. 5, and FIG. 7B is a partially enlarged view of the 0-B section of FIG.

FIG. 8 is a vertical cross-sectional view that emphasizes the behavior of the wafer when the wafer is taken in and out of the wafer by the end effector. BEST MODE FOR CARRYING OUT THE INVENTION

An example of the best embodiment of the present invention will be described below with reference to FIGS. Note that the following embodiments do not limit the scope of the present invention. That is, Anyone can adopt another embodiment within the scope of the principle of the present invention. The wafer carrier 121 of this embodiment can hold a plurality of disc-shaped wafers 123 horizontally. In the following, a description will be given of a state in which a wafer 23 is taken in and out from the near side (the right side in FIG. 1). That is, the wafer carrier 21 is provided on the side walls 25 erected on the left and right, the upper horizontal member 27 and the lower horizontal member 29 connecting these side walls 25, and the left and right side walls 25. And 30 teeth.

The side wall portion 25 has a flat plate portion 31 having a linear cross section on the front side and an arc portion 33 on the back side, and both 31 and 33 are separately formed and screwed on the divided surface. Stopped at 3 4 As a result, the left and right side walls 25 are paired to form a substantially U-shaped flat surface. Due to the U-shape, a part of the inner peripheral wall 35 for accommodating the disc-shaped wafer 23 is formed, and interference between the wafer 23 to be taken in and out and the side wall 25 is avoided. Can be In the arc portion 33, a window 37 is formed in the center portion, and the teeth 30 are exposed. The rear end of the arc portion 33 is bent rearward to form a bent portion 39. The bent portions 39 of the left and right side wall portions 25 are separated from each other, and are open during the separation, so that the teeth 30 are exposed. In addition, the side wall part 25 has a leg part 41 protruding left and right at a lower part, and stabilizes the entire wafer-carriage-one 21. The teeth 30 are provided to hold a plurality of wafers 23 in parallel apart from each other and to allow the wafers 23 to be taken in and out from the near side. The side walls 25 forming the inner peripheral wall 35 of the wafer carrier 21 are provided. It is fixed to the inner surface of. The teeth 30 provided on the left and right side walls 25 form a pair and hold the peripheral edge of each wafer 23 from the left and right. Each tooth 30 holds the left and right peripheral portions of each wafer 23 on the front side as well as the back side from the center of the wafer 23, and thus the two sides (4) The inner peripheral edge 47 of an arc shape for holding the peripheral edge of the wafer 23 has substantially the same length, and is thus symmetrical between the back side and the near side. I have.

The back side divided portion 43 is fixed to the flat plate portion 31 and the bent portion 39 across the window 37 portion. The near side divided portion 47 is fixed to the flat plate portion 31. Further, the near side divided portion 47 forms a protruding portion 49 having a protruding shape. In the vicinity of the inner peripheral wall 35, that is, in the vicinity of the center of the wafer 13 in the front-rear direction, the vertical cross section of the teeth 30 group The shape has a continuous waveform (FIG. 3 (B)), and the protruding portion 49 has an intermittent shape so as not to interfere with the end effector and the wafer 23 which are taken in and out (FIG. 3 (C)). ).

The distance between the tips of the protrusions 49 formed on the left and right is 15 mm or more within 90 mm.

The distance L between the teeth 30 is 6.35 mm as in the conventional case. The dimension F of the flat part called pocket flatness of the pocket 51 formed by the valleys of the waveforms of the continuous waveform cross-sections of the group of teeth 30 is 3 mm or more and 4.5 mm or less.

The end effector 53 shown in FIG. 4 is used for loading and unloading the wafer 23. The end effector 53 has a ring-shaped portion 55 with an open end, and a grip portion 59 is formed on the opposite side of the opening 57.

[Action and effect]

In order to remove one wafer 23 from the plurality of held wafers 23, the end effector 53 is inserted between the wafers 23 and brought into contact with the lower surface of the wafer 23. And lift. Then, first, the wafer is lifted up by the dimension of the warp 1, and the warp 1 disappears, and the wafer 23 becomes flat.

At this time, the protrusions 49 formed on the teeth 30 hold the wafer 23 symmetrically not only on the back side but also on the front side, so that the warp Δ 1 on the front side is smaller than in the conventional asymmetric case. It can be avoided that it grows larger. In addition, the teeth 30 do not interfere with the end effector 53 because the cross-section of the protrusions 49 has an intermittent shape at the protruding portions 49, and therefore, the protruding portions 49 are sufficiently positioned on the near side. It is possible to enlarge the part that holds the wafer 23. Therefore, the near-side warp Δ1 can be further reduced. The warp Δ1 can be made sufficiently small by keeping the distance between the front and rear ends of the protruding portions 49 within 90 mm, thereby reducing the distance between the held wafers and the outer dimensions of the wafer carrier. It is also possible to leave it unchanged. In addition, by setting the distance between the tips to be 15 mm or more, the gripping portion 59 of the end effector that passes through the space does not need to be very thin, and the strength of the gripping portion 59 may be insufficient. Can be eliminated. This 15 mm limit is also required in relation to other equipment. That is, the wafer carrier 21 is erected, whereby the wafer 23 is erected vertically, the opening of another apparatus is positioned below the wafer carrier 21, and the roller 1 is attached to the wafer 2. In some cases, the wafer is rotated by contacting the lower part of the wafer 3 and the wafers 23 are rotated to align the notches on each wafer 123. In order to avoid interference with 49, the spacing should be at least 15 mm.

Furthermore, the contact with the teeth 23 is removed by lifting the size of the saucer 2. At this time, since the protruding portion 49 has an intermittent shape in cross section, it does not interfere with the end effector 53, so that a wide end effector 53 can be used, and thus the protrusion Δ2 Can be reduced.

After that, it needs to be lifted by P to get further away from teeth 30.

Therefore, since the warp 1 and the sag Δ2 can be reduced, the distance L between the wafers 23 can be reduced.

L> Δ 1 + Δ 2 + P

Can be sufficiently satisfied.

In addition, apart from the problem of the distance L between the wafers 13, the area dimension P for the pickup must have a sufficiently large value so as not to come into contact with the upper teeth 30. In particular, if the sag Δ2 is a large value, both ends of the wafer 23 will be held diagonally in the pockets 51 of the teeth 30, and the dimensions of the pockets 51 will not be sufficiently used during pickup. However, in the present embodiment, the dimension F of the flat portion of the pocket 51 is increased to 3 mm or more so that the dimension of the pocket can be sufficiently increased. It can be used to increase the area size P for pick-up.

By setting the dimension F within 4.5 mm, the teeth 30 can be sufficiently formed even if the interval L between the teeth 30 is set to 6.35 mm as in the conventional case. That is, dimensions If F is 4.5 mm, the thickness of teeth 30 is

(6.35-4.5) = 1.85 [mm]

Thus, the thickness required for the flow of the resin in the case of injection molding with a resin and the thickness required for the strength in the case of roll molding with a metal can be satisfied.

[Other embodiments]

In the above embodiment, a completely dedicated wafer—a carrier 21 is used separately from the conventional wafer carrier 11; in other embodiments, the conventional wafer carrier 11 is used. There may be.

That is, as shown in FIG. 5, a thin arc-shaped fitting tooth 61 formed separately is fitted into the tooth 7 of the conventional wafer carrier 11, and the wafer 1 3 may be held.

The conventional wafer / carrier 11 used is for a large-sized wafer. In FIG. 5, the same parts as those in FIG. 3 are denoted by the same reference numerals. Industrial applicability

As described above, according to the first, second, or third invention, since the wafer is held not only on the back side but also on the front side by the projections formed on the teeth, the warp Δ1 is reduced on the front side. It is possible to avoid further increase in size, and to reduce the problem of a decrease in the number of stored sheets and the adverse effect on the crystal.

Also, it is possible to avoid changing the distance between the held wafers and the outer dimensions of the wafer carrier. In the latter half of the process, it is possible to share the wafer and carrier used. This makes it possible to use equipment used in the first half of the process, such as insulators, buffers, and conductive area formation devices, in the second half of the process without much modification. Can be reduced. In addition, the downward warpage Δ1 that has increased on the front side of the wafer can be reduced, and physical and mechanical adverse effects on crystals on the surface of the wafer can be suppressed. Also, since the teeth have an intermittent cross section at the protruding part, use a wide end effector so that the end effector and the wafer do not interfere with the teeth when inserting and removing the wafer. Therefore, the size of the drop 2 can be reduced. In addition, the protrusion can be made sufficiently large on the near side, and the portion for holding the wafer can be made large, so that the warpage Δ1 on the near side can be reduced.

According to the fourth invention, even if the sag 2 of the wafer 1 exists at a large value and both ends of the wafer 1 are positioned obliquely to the pocket at the time of pick-up, the flat portion having the wave-shaped valley portion forming the pocket has By increasing the dimensions of the important parts, the dimensions of the pocket can be used sufficiently, and the area dimension Ρ for the pickup can be increased.

The scope of the claims

1. Wafer carrier with the following configuration for storing and transporting wafers o

a. A plurality of wafers are provided on the inner peripheral wall of the wafer and one carrier to hold a plurality of the wafers in parallel at a distance from each other so that they can be taken in and out from the near side, and a plurality of wafers holding the peripheral edge of each wafer from the left and right. Teeth and

b. a protruding portion formed on each of the teeth and having an arc-shaped inner peripheral portion to hold the left and right peripheral portions of the respective wafers not only on the rear side but also on the near side from the center of the wafer;

c. The vertical cross-sectional shape of the teeth group, which has a continuous waveform near the inner peripheral wall of the wafer carrier 1 and the projecting portion does not interfere with the end effector or the wafer to be taken in and out. A longitudinal cross-sectional shape with an intermittent shape.

2. The car carrier according to claim 1, wherein the arc-shaped inner peripheral edge portion is symmetrical on a back side and a near side.

3. The wafer carrier according to claim 2, wherein the distance between the tips of the protrusions formed on the left and right is not more than 90 mm and not less than 15 mm.

4. Wafer carrier with the following configuration for storing and transporting wafers.

a. A plurality of teeth provided on the inner peripheral wall of the wafer carrier 1 for holding the plurality of wafers parallel to each other at a distance from each other and allowing the wafers to be taken in and out from the front side, and holding the peripheral edge of each wafer from the left and right. When,

b. The vertical cross-sectional shape of the teeth group, which has a continuous waveform near the inner peripheral wall of the wafer carrier 1. The flat portion of the valley portion of the waveform has a dimension of 3 mm or more and 4. Longitudinal cross section within 5 mm.

Claims

Claims of amendment [May 7, 2001 (07.05.01) Accepted by the International Bureau: Claims 1 and 4 originally filed have been amended; other claims remain unchanged. (2 pages)]

1. (After correction) A wafer carrier with the following configuration, which holds a plurality of wafers parallel to each other, and stores and transports wafers so that they can be taken in and out from the near side.

a. Left and right side walls and upper and lower horizontal members,

b. a plurality of teeth provided on the inner peripheral wall of the side wall to hold the peripheral edge of each wafer from the left and right;

c to hold the left and right peripheral portions of each of the wafers not only on the back side but also on the near side from the center of the wafer, a projection having an arc-shaped inner peripheral portion formed on each of the teeth,

d. The vertical cross-sectional shape of the plurality of teeth has a continuous waveform near the inner peripheral wall of the wafer carrier, and the projecting portions are intermittent so as not to interfere with the end effector to be taken in and out and the wafer. When the distance between the teeth and the arc-shaped inner edge are L: teeth distance, Δ1: wafer warpage, Δ2: wafer sagging, and P: wafer pick-up dimension ,

L> Δ 1 + m 2 + P

It is.

2. The wafer carrier according to claim 1, wherein the arc-shaped inner peripheral edge is symmetrical on a back side and a near side.

3. The wafer carrier according to claim 2, wherein the distance between the tips of the protrusions formed on the left and right is 15 mm or more within 90 mm.

4. (After correction) A wafer carrier with the following configuration, which holds a plurality of wafers parallel to each other, and stores and transports them so that they can be taken in and out from the near side.

a. Left and right side walls and upper and lower horizontal members,

c The plurality of teeth are: L: tooth spacing, Δ1: wafer warpage,

13

'Kusu's paper (Article 19 of the Convention) Δ 2: sagging of wafer, P: when assuming the pickup size of wafer, L> Δ 1 + Δ 2 + P

And

d. The vertical cross-sectional shape of the teeth group has a continuous waveform near the inner peripheral wall of the wafer carrier, and the flat portion of the valley of the waveform has a dimension of 3 mm or more and 4.5 mm or less. .

14

'Paper on Kusunoki Tadashi (Article ^ of the Convention)

Statements under Article 19 of the Convention

1. Claims 1 and 4 refer to a wafer-to-carrier, which holds a plurality of thinner wafers than before and keeps them parallel to each other, and stores and transports wafers so that they can be taken in and out from the near side. Yes, the claims have been amended to clarify this point.

2. Reference 1 (USP. No. 6074515) is a carrier that holds the wafer horizontally and moves the wafer from the front to the back and moves it to the processing chamber. . In particular, it is not a carrier for holding a thin wafer.

Reference 2 (USP. No. 5577621) is a wafer carrier for accommodating and holding wafers of different sizes.The teeth have an arc shape, and the teeth accommodate wafers of different sizes. It has recesses of different possible diameter dimensions.

3. Unlike the cited examples, the invention of the present application has a particularly limited interval between the teeth, and thus has an advantage that a thinner wafer than before can be accommodated.