This application claims the priority benefit of French Application for Patent No. 2106460, filed on Jun. 17, 2021, the content of which is hereby incorporated by reference in its entirety to the maximum extent allowable by law.
The present disclosure relates to electronic chips in general and, more particularly, to the manufacture of such electronic chips.
In industry, most electronic devices are manufactured in series. Generally, several copies of the same electronic device are manufactured simultaneously in and on the same plate, known as a wafer.
The number of electronic chips that can be placed on the same wafer depends on the chip dimensions and the spacing between them. This spacing is determined by taking into account different constraints such as the precision with which different manufacturing steps are performed, the technology used to separate the chips from each other or the placing of ephemeral elements on the board.
It would be desirable to be able to improve the electronic chips and their manufacturing methods, at least in part.
There is a need for microchip manufacturing methods that make it possible to manufacture more chips on a single wafer.
One embodiment addresses all or some of the drawbacks of known electronic integrated circuit chips manufacturing methods.
One embodiment addresses all or some of the drawbacks of known electronic chips. One embodiment provides for an electronic chip comprising a seal ring whose shape is contained within a rectangle of a width equal to the maximum width of said chip and of a length equal to the maximum length of said chip, and at least one test pad arranged in said rectangle, at least partially, said test pad being shared with at least one other electronic chip.
According to one embodiment, said test pad is arranged outside of said seal ring.
According to one embodiment, said seal ring has a substantially rectangular-shaped recess at the location of said test pad, said test pad being embedded in said recess.
According to one embodiment, the chip comprises at least one circuit arranged in an area of the same size as the recess and arranged against a first side of the chip opposite a second side of the chip on the side of which said recess is formed, said circuit being a circuit whose position in said chip can be modified.
According to one embodiment, said test pad is arranged on a cutting line that makes it possible to individualize said chip at the end of its manufacturing method.
According to one embodiment, said test pad is positioned next to a cutting line that makes it possible to individualize said chip at the end of its manufacturing method.
According to one embodiment, said test pad is arranged inside said seal ring, and said seal ring has the shape of said rectangle.
According to one embodiment, said test pad is shared with a group of electronic chips. According to one embodiment, said test pad is connected to said other electronic chip by a communication bus made of a non-metallic material.
According to one embodiment, said communication bus is made of polycrystalline silicon.
Another embodiment provides a method for manufacturing a group of electronic chips described above, comprising a step of individualizing the chips performed by a particle beam cutting method.
According to one embodiment, the particle beam cutting method is a plasma cutting method.
According to one embodiment, the particle beam cutting method is associated with a laser cutting method.
According to one embodiment, the electronic chips are spaced apart from each other by a minimum spacing defined by the cutting method.
According to one embodiment, the spacing of the chips is greater than or equal to 15 μm.
The foregoing features and advantages, as well as others, will be described in detail in the following description of specific embodiments given by way of illustration and not limitation with reference to the accompanying drawings, in which:
Like features have been designated by like references in the various figures. In particular, the structural and/or functional features that are common among the various embodiments may have the same references and may dispose identical structural, dimensional and material properties.
For the sake of clarity, only the operations and elements that are useful for an understanding of the embodiments described herein have been illustrated and described in detail. In particular, the manufacturing steps of the circuits included in an electronic chip are not described here, with the usual manufacturing steps of these circuits being compatible with the described embodiments.
Unless indicated otherwise, when reference is made to two elements connected together, this signifies a direct connection without any intermediate elements other than conductors, and when reference is made to two elements coupled together, this signifies that these two elements can be connected or they can be coupled via one or more other elements.
In the following disclosure, unless indicated otherwise, when reference is made to absolute positional qualifiers, such as the terms “front”, “back”, “top”, “bottom”, “left”, “right”, etc., or to relative positional qualifiers, such as the terms “above”, “below”, “higher”, “lower”, etc., or to qualifiers of orientation, such as “horizontal”, “vertical”, etc., reference is made to the orientation shown in the figures.
Unless specified otherwise, the expressions “around”, “approximately”, “substantially” and “in the order of” signify within 10%, and preferably within 5%.
The electronic chips 12 are arranged in array form, that is, in lines and columns. The chips 12 are identical circuits manufactured in series in and on the wafer 10, for example, but, in a variant, may be different circuits but of similar size, for example, in order to be able to optimize the distribution of circuits 12 on the wafer 10.
The electronic chips 12 are all formed simultaneously on the wafer 10. Once the manufacture and assembly of circuits of the chips 12 is complete, compliance tests should be performed. These tests are performed using test pads connected to the chips, not shown in
The chips 12 can then be separated, or individualized, through a singulation process so that they can be used on their own, for example, or in a more complete electronic system. To individualize the chips 12, the wafer 10 can be cut along cutting lines 14, designated as dotted lines in
The electronic chip 20 is substantially rectangular or rectangular in shape, or substantially square or square in shape, and includes at least one functional circuit 21 formed in an area designated by dotted lines. The electronic chip 20 generally comprises a plurality of functional circuits 21 connected to each other, by conductive tracks, for example. The functional circuit 21 may or may not be protected by a housing.
The functional circuit 21 is surrounded by a seal ring 22 that defines the edge of the chip 20. In the following description, the shape of an electronic chip will be considered defined by the shape of its seal ring. The seal ring 22 may be composed of a stack of interconnecting metal layers comprising a network of vias. A metal layer of this stack may be connected to an active layer of the wafer or plate in and on which the chip 20 is formed. The active layer may be a layer of the same doping type as the wafer, for example. The seal ring 22 provides mechanical protection of the edges of the chip 20, and protection of the chip 20 from diverse contamination, such as corrosion. The seal ring 22 may further make it possible to connect to a reference potential, such as ground, of the circuit periphery of the chip 20.
The electronic chip 20 may comprise one or more connection pads 23, accessible for connecting the chip 20 to other chips, circuits, or electronic components. In
The electronic chips 30 are chips of the type of chip 20 described in connection with
The chips 30 have all been formed on a plate (not shown), or a wafer, in the manner of the chips 12 described in connection with
As described in connection with
In the example shown in
In the step shown in
The spacing of the chips 30 is thus constrained by the placing of the test pads 32 and by the cutting method used to individualize the chips 30. The spacing EC3 of two columns of chips 30, constrained by the placing of test pads 32, has a minimum dimension of 80 μm. The spacing EL3 of two rows of chips 30, constrained by the cutting method used, has a minimum dimension of 60 μm.
It would be desirable to be able to decrease the spacing EC3 and EL3 of the chips 30, so as to be able to position more chips 30 on the same plate or on the same wafer.
The chips 40A and 40B are similar to the chips 30 described in connection with
Thus, each chip 40A, 40B comprises one or more functional circuits, a portion of which is described in more detail below, surrounded by a seal ring 41 defining the shape of the chip 40A, 40B, and four connection pads 42.
In addition, each group 40 is similar to a group 34 described in connection with
The number of test pads 45 comprised in the group 40 is varies, depending on the nature of the compliance tests applied to the chips 40A and 40B. According to one example embodiment, each test group 40 comprises at least one test pad 45, such as three test pads 45. According to one example, one test pad may receive an input test signal, one test pad may transmit an output test signal, and a final test pad may provide a reference potential, such as ground.
As illustrated in
Unlike the chips 12, 20, and 30, the chips 40A and 40B are individualized by using a cutting method comprising a particle beam cutting method, accompanied or not by a laser cutting method. The particle beam and laser cutting methods impose fewer chip spacing constraints 40A and 40B as compared to the saw cutting methods. In particular, the particle beam and laser cutting methods make possible more accurate and faster cutting of a plate, or wafer, on which the chips 40A and 40B are formed. The particle beam and laser cutting methods thus make it possible to reduce the spacing of the lines EL4 of the chips 40A and 40B and the spacing of the columns EC4 of the chips 40A and 40B. According to one embodiment, the particle beam cutting method is a plasma cutting method, which makes it possible to reduce the spacings EL4 and EC4 to a minimum dimension of 15 μm. According to one example embodiment, the spacings EL4 and EC4 are of the order of 26 μm.
An example of a cutting method making it possible to individualize the chips 40A and 40B may comprise the following successive steps:
However, placing the test pads 45 between the chips 40A and 40B of the same group 40 prevents reducing the spacing of the rows and columns of chips 40A and 40B to the permitted minimum. For this reason, according to one embodiment, the chips 40A and 40B, and thus their seal ring 41, no longer have a rectangular or substantially square shape, but have a shape contained within a rectangle or a square of a width equal to the maximum chip width and of a length equal to the maximum chip length. In addition, according to one embodiment, the shape of the chips 40A and 40B includes a recess 43 on the side near which the test pads 45 are positioned. The recess 43 conforms to the shape of the test pads 45, so as to embed a portion of the test pads 45 into the chips 40A and 40B, and to make it possible for the chips 40A and 40B to be spaced apart by a minimum spacing that depends on the cutting method used and not on the size of the test pads. According to one embodiment, the recess 43 is substantially rectangular in shape. Since the test pads 45 are positioned between the chips 40A and 40B of the same group 40, the recess 43 is not positioned on the same side on the chip 40A and on the chip 40B. In
In order to optimize the space delimited by the seal ring 41 of the chips 40A and 40B, an area 47 (shaded in
One advantage of this embodiment is that it makes it possible to reduce the spacing, that is, to bring the chips 40A and 40B closer together.
The group 50 and the chips 50A and 50B are similar to the group 40 and the chips 40A and 40B described in connection with
Thus, each chip 50A, 50B comprises one or more functional circuits, a portion of which is described in more detail below, surrounded by a seal ring 51 that defines the shape of the chip 50A, 50B, and four connection pads 52.
In addition, each group 50 thus includes two adjacent chips 50A and 50B, between which test pads 55 identical to the test pads 32, described in connection with
Unlike the group 40 of
As described in connection with
Furthermore, the test pads 55 embedded in the chip 50A or 50B, respectively, are electrically connected to each of the chips of the group 50, and in particular to the other chip, that is, the chip 50B or 50A, respectively, by buses 58. Each bus 58 comprises one or more conductive strips of a material that can be cut by the same cutting method as the plate on and in which the chips 50A and 50B are formed. According to one embodiment, if the plate cutting method is a plasma cutting method, the buses 58 may be made of polycrystalline silicon.
One advantage of this embodiment is that it makes it possible to economize on a laser cutting method for cutting the test pads 55 if their material is unsuitable for cutting by a particle beam cutting method, such as a plasma cutting method.
One example of a cutting method for individualizing the chips 50A and 50B may include the following sequential steps:
The group 60 and the chips 60A and 60B are similar to the group 50 and the chips 50A and 50B described in connection with
Thus, each chip 60A, 60B comprises one or more functional circuits surrounded by a seal ring 61 that defines the shape of the chip 60A, 60B, and four connection pads 62.
In addition, each group 60 thus comprises two adjacent chips 60A, 60B, between which test pads 65, identical to the test pads 32 described in connection with
The group 60 overcomes one drawback of the group 50, in which the chips 50A and 50B are not the same shape, which can lead to problems when using the chips 50A and 50B. Indeed, positioning errors can be generated by the difference in shape of the chips 50A and 50B.
In the group 60, the recess 63 of the chip 60A or the recess 63 of the chip 60B are positioned on the same side of the chip 60A or 60B, such as the left side in
To connect the test pads 65 to the chips 60A and 60B, each test pad 65 is connected to a bus 68, of the same type as the bus 58 described in connection with
One advantage of this embodiment is that the chips 60A and 60B have the same shape. To make the chips 60A and 60B even more similar, dummy conductive tracks can be formed in the chip not requiring conductive tracks 69, the chip 60B in the case of
The person skilled in the art will know how to adapt this embodiment by placing the test pads on either side of the chips 60A and 60B.
The group 70, and the chips 70A and 70B are similar to the group 60, and the chips 60A and 60B described in connection with
Each group 70 thus comprises two adjacent chips 70A and 70B and an even number of test pads 75. Each chip 70A, 70B includes one or more functional circuits surrounded by a seal ring 71 that defines the shape of the chip 70A, 70B, and four connection pads 72.
Unlike the embodiments of
Thus, the chips 70A and 70B, and thus their seal rings, are substantially rectangular or substantially square in shape and do not have any recesses at the test pads. One advantage of this embodiment is that the seal rings 71 of the chips 70A and 70B do not have a concave portion.
One advantage of this embodiment is that the chips 70A and 70B have a more compact shape and are easier to manufacture. Indeed, it is potentially more reliable to make a rectangular or square shaped seal ring without a recess.
Unlike the group 70, the group 80 comprises four integrated circuit chips 80A, 80B, 80C and 80D arranged in two rows and two columns. According to one example, in
The chips 80A, 80B, 80C, and 80D are similar to the chips 70A and 70B, Each chip 80A, 80B, 80C, and 80D includes one or more functional circuits surrounded by a seal ring 81 that defines the shape of the chip 80A, 80B, 80C, and 80D, and four connection pads 82.
In addition, as with the group 70, the group 80 uses four test pads 85 to implement the compliance test methods for chips 80A through 80D. As a result, unlike the chips 70A and 70B, the chips 80A through 80D each comprise a single test pad 85 positioned within their seal ring 81.
In the embodiment shown in
In the example shown in
In the example of
Various embodiments and variants have been described. Those skilled in the art will understand that certain features of these embodiments can be combined and other variants will readily occur to those skilled in the art. In particular, the person skilled in the art will know how to adapt the described embodiments to more than two or four chips in a group, and to a different number of test pads per chip group.
Finally, the practical implementation of the embodiments and variants described herein is within the capabilities of those skilled in the art based on the functional description provided hereinabove.
Number | Date | Country | Kind |
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2106460 | Jun 2021 | FR | national |