Tool clamp for probe sheet

Abstract

The invention discloses a tool clamp for a probe sheet. The tool clamp comprises a support; the clamping mechanism comprises a base plate movably supported on the support and a clamping pressing plate detachably connected to the base plate, the base plate is provided with a first contour hole which penetrates through the base plate and is matched with the probe sheet in shape, and the clamping pressing plate is provided with a second contour hole which corresponds to the first contour hole and penetrates through the clamping pressing plate; a first clamping part is arranged on the inner peripheral edge of the first contour hole, a second clamping part corresponding to the first clamping part is arranged on the inner peripheral edge of the second contour hole, and the first clamping part and the second clamping part can jointly clamp the probe sheet between the substrate and the clamping pressing plate; and the electric connection structure comprises a conductive pressing plate detachably connected to the substrate, an accommodating space formed between the substrate and the conductive pressing plate in a clamping manner, and a conductive part of which one part is arranged in the accommodating space and is in conductive contact with at least part of the probe sheets, and the conductive part is suitable for being electrically connected with an electrode of a power supply.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor wafer test probes, and in particular to a tooling fixture for a probe sheet of a probe card. Background Art

[0002] MEMS vertical probe card is a precision device for semiconductor testing. It is manufactured by micro-electromechanical system (MEMS) technology and can achieve high-density, high-pin count probe arrangement to meet the test requirements of high pin count, high current and high probe compression stroke. This probe card is particularly suitable for testing small-pitch, high-frequency chips, such as wafer testing of CPU, GPU, SoC and other products. MEMS vertical probe card usually consists of three parts: PCB, space converter (such as MLO, MLC or WST) and probe head (usually a machinable ceramic sheet). They use a short needle-like structure perpendicular to the substrate to meet the test requirements of small-pitch and high-frequency chips. In related technologies, probe cards usually use probe sheets to install probe heads, process pin holes at the UD (Upper Die, i.e. the top chip of the stacked chip) and LD (Lower Die, i.e. the bottom chip of the stacked chip) positions of the probe sheets, and then insert tens of thousands of MEMS probes into the pin holes. To ensure that each probe works properly, the dimensional accuracy of the probe is very high. When making a pin hole on a probe sheet, the probe shape is usually cut out on the probe sheet by laser cutting or wire cutting. At the same time, the probe sheet needs to be subjected to multiple wet process treatments (such as immersing the cut probe sheet in a cleaning tank, pickling tank and electroplating tank for corresponding surface cleaning, pickling, electroplating, etc.) to remove dirt, impurities, oxide films, etc. on the surface of the probe sheet and form a metal coating on the probe sheet to improve the physical properties of the probe sheet. The square pin hole after cutting needs to be plated with metal coatings on the four walls of the front, back, left and right. Since the cut probe sheet is narrow and the thickness is usually less than 0.2 mm, it is difficult to clamp during wet process treatment, and the probe sheet without fixing measures or with unsatisfactory fixing effect is prone to warping and deformation during the wet process treatment, and this warping and deformation is mostly seen at the outer contour edge of the probe sheet, making it difficult to ensure the uniformity of the metal coating formed on the surface of the probe sheet. In addition, the poor electrical contact between the probe sheet and the electrode of the external power supply during the electroplating process can also easily reduce the electroplating effect. Therefore, there is an urgent need for a tooling fixture suitable for clamping probe sheets so that the probe sheets can be immersed in a wet process tank for corresponding wet process treatment to avoid defects such as warping and poor electroplating uniformity of the probe sheets during the wet process treatment. Summary of the invention

[0003] In order to solve the above technical problems, the purpose of the present invention is to provide a tooling fixture for a probe sheet, which is suitable for clamping the probe sheet and immersing it in a wet process treatment tank for corresponding wet process treatment, and can avoid the defects of warping and poor electroplating uniformity of the probe sheet during the wet process treatment.

[0004] On the one hand, the present invention provides a tooling fixture for a probe sheet, which is suitable for clamping the probe sheet so as to be immersed in a wet process treatment tank for treatment, and the tooling fixture comprises: a bracket, which is constructed to be suitable for supporting the upper part of the wet process treatment tank; a clamping mechanism, including a substrate movably supported on the bracket, and a clamping plate detachably connected to the substrate, wherein the substrate is provided with a first contour hole that passes through the substrate and is adapted to the shape of the probe sheet, the clamping plate is provided with a second contour hole corresponding to the first contour hole and passing through the clamping plate, and the inner peripheral edge of the first contour hole is provided with at least one A first clamping portion, the inner peripheral edge of the second contour hole is provided with at least one second clamping portion corresponding to the at least one first clamping portion, and the at least one first clamping portion and the at least one second clamping portion can jointly clamp the probe sheet between the substrate and the clamping pressure plate; an electrical connection structure, including a conductive voltage plate detachably connected to the substrate, a receiving space sandwiched between the substrate and the conductive voltage plate, a conductive member partially installed in the receiving space and in conductive contact with at least part of the probe sheet, and another part of the conductive member is constructed to be suitable for electrical connection with an electrode of a power source.

[0005] According to an embodiment of the present invention, a plurality of the first clamping portions are disposed at intervals on the inner peripheral edge of the first contour hole, and a plurality of the second clamping portions are disposed at intervals on the inner peripheral edge of the second contour hole.

[0006] According to one embodiment of the present invention, the substrate and the clamping plate are detachably connected through a staple assembly, a first mounting hole is provided on the substrate, and a second mounting hole corresponding to the first mounting hole is provided on the clamping plate, the staple assembly includes a staple piece inserted into the mounting hole, a spring sleeved on the outside of the staple piece, and the staple piece includes a staple head, a staple rod connected to the staple head, and a pair of elastic barbs connected to the staple rod.

[0007] According to one embodiment of the present invention, the conductive member includes a conductive sheet installed in the receiving space, and a conductive connecting portion connected to the conductive sheet and extending outward, and the conductive connecting portion is constructed to be suitable for electrical connection with an electrode of a power source.

[0008] According to an embodiment of the present invention, the conductive connecting portion extends upward and passes through the bracket.

[0009] According to an embodiment of the present invention, the conductive member is one of metal foil, metal plate, metal sheet and conductive cable.

[0010] According to one embodiment of the present invention, it also includes a height adjustment mechanism for adjusting the height of the clamping mechanism relative to the bracket, and the height adjustment mechanism includes a mounting groove opened on the bracket, an adjustment frame movably installed in the mounting groove along the up-down direction and connected to the clamping mechanism, a plurality of limit sockets arranged on the adjustment frame at intervals along the up-down direction, and a limit plug-in that is detachably plugged into the limit socket and supported on the bracket.

[0011] According to an embodiment of the present invention, the adjustment frame is detachably connected to the substrate or the conductive voltage plate.

[0012] According to an embodiment of the present invention, the adjustment frame includes two adjustment rods arranged opposite to each other, and the limiting plug holes are provided on the two adjustment rods.

[0013] According to an embodiment of the present invention, the height adjustment mechanism further comprises a handle connected between the two adjustment rods.

[0014] Compared with the prior art, the present invention has the following beneficial effects: By setting a first contour hole that matches the shape of the probe sheet on the substrate and setting at least one first clamping portion on the inner peripheral edge of the first contour hole, setting a second contour hole on the clamping plate and setting at least one second clamping portion on the inner peripheral edge of the second contour hole, at least one first clamping portion and at least one second clamping portion can jointly clamp the probe sheet between the substrate and the clamping plate, so that the probe sheet can be clamped and fixed along the outer contour edge, which can avoid the warping deformation of the probe sheet during the wet process treatment and avoid the defect of poor uniformity of the metal electroplating layer formed on the surface of the probe sheet. Secondly, a conductive member that is in conductive contact with the probe sheet is installed in the receiving space between the substrate and the conductive plate, so that the probe sheet always maintains an electrical connection with the electrode of the power supply during the wet process treatment, ensuring the continuity and stability of the electroplating. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a three-dimensional diagram of a fixture according to an embodiment of the present invention; Figure 2 yes Figure 1 An exploded perspective view of the jig shown in FIG. Figure 3 yes Figure 2 A local enlarged view of point A shown in FIG; Figure 4 yes Figure 1 A side plan view of the jig shown in FIG. Figure 5 yes Figure 4 The cross-sectional view along line BB is shown in; Figure 6 yes Figure 5 The local enlarged view of point C shown in FIG. Figure 7 yes Figure 1 A cutaway perspective view of the layout of the fixture shown in FIG. Figure 8 yes Figure 7 A local enlarged view of point D is shown in FIG.

[0016] The reference numerals are as follows: 100, fixture; 200, probe sheet; 201, needle hole; 202, through hole; 10. bracket; 11. support; 111. limit groove; 12. limit baffle; 20. Clamping mechanism; 21. Base plate; 211. First contour hole; 212. First clamping portion; 213. First mounting hole; 214. First positioning hole; 22. Clamping plate; 221. Second contour hole; 222. Second clamping portion; 223. Second mounting hole; 224. Second positioning hole; 30. Electrical connection structure; 31. Conductive voltage plate; 32. Accommodating space; 33. Conductive member; 331. Conductive sheet; 332. Conductive connection part; 40. Height adjustment mechanism; 41. Mounting slot; 42. Adjustment frame; 421. Adjustment rod; 43. Limiting jack; 44. Limiting plug-in; 45. Handle; 50. staple assembly; 51. staple piece; 511. staple head; 512. staple rod; 513. elastic barb; 52. spring. DETAILED DESCRIPTION

[0017] It is easy to understand that according to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific implementation modes and drawings are only exemplary descriptions of the technical solution of the present invention, and should not be regarded as the whole of the present invention or as a limitation or restriction to the technical solution of the present invention.

[0018] In one embodiment of the present invention, a fixture 100 for a probe sheet 200 is provided, and the fixture 100 is suitable for clamping the probe sheet 200 so as to be immersed in a wet process tank / tank for corresponding process treatment. The structural composition and principle of the fixture 100 of the embodiment of the present invention are described in detail below according to the drawings of the specification.

[0019] according to Figure 1 and Figure 2 As shown, the fixture 100 includes a bracket 10 and a clamping mechanism 20. The bracket 10 is constructed to be suitable for supporting the upper part of the wet process treatment tank / tank. The bracket 10 includes a support 11 and limit baffles 12 installed on the two opposite sides of the support 11. The support 11 can be supported on the upper part of the wet process treatment tank / tank, and the two limit baffles 12 limit the support 11 on the upper part of the wet process treatment tank / tank, thereby limiting the movement of the support 11 on the wet process treatment tank / tank, and preventing the fixture 100 from accidentally falling into the wet process treatment tank / tank due to vibration when the probe sheet 200 is clamped and immersed in the wet process treatment tank / tank for corresponding process treatment (such as surface cleaning, pickling, electroplating, etc.). Among them, the limit baffle 12 is installed on the opposite side parts of the support 11 by fasteners such as screws. In other embodiments, the connection relationship between the limit baffle 12 and the support 11 can also be magnetic connection, adhesive connection, snap connection, hinged or welded, without specific limitation.

[0020] The clamping mechanism 20 includes a substrate 21 and a clamping plate 22. The substrate 21 is provided with a first contour hole 211 that penetrates the substrate 21 and matches the outer shape of the probe sheet 200. The clamping plate 22 is installed on the substrate 21. The clamping plate 22 is provided with a second contour hole 221 that corresponds to the first contour hole 211 and penetrates the clamping plate 22. Six first clamping portions 212 are provided on the inner peripheral edge of the first contour hole 211, and six second clamping portions 222 corresponding to the six first clamping portions 212 are provided on the inner peripheral edge of the second contour hole 221. When clamping the probe sheet 200, the substrate 21 and the clamping plate 22 jointly clamp the probe sheet 200 therebetween, and the outer contour edge of the probe sheet 200 is clamped and clamped by the six first clamping portions 212 and the six second clamping portions 222.

[0021] Among them, the shape of the probe sheet 200 is similar to a fan shape, and the shape of the first contour hole 211 opened on the substrate 21 and the shape of the second contour hole 221 opened on the clamping plate 22 both correspond to the outer shape of the probe sheet 200, and are also similar to a fan shape. For the tooling fixture 100, when the tooling fixture 100 clamps the probe sheet 200 and immerses it in the wet process treatment tank / pool for corresponding wet process treatment, both sides of the probe sheet 200 can better contact and react with the treatment solution in the wet process treatment tank / pool, and the outer contour edge of the probe sheet 200 is clamped and fixed, which can also avoid the probe sheet 200 from warping and deformation during the wet process treatment, and other defects that affect the wet process treatment. In other embodiments, the first contour hole 211 of the substrate 21 and the second contour hole 221 of the clamping plate 22 can be set according to the specific shape of the probe sheet 200, so that the first contour hole 211 and the second contour hole 221 match or coincide with the outer shape of the probe sheet 200; in addition, the first contour hole 211 and the second contour hole 221 can also be set to a regular shape, such as a circle, a rectangle, etc., without specific limitation.

[0022] In order to facilitate the probe sheet 200 to be more evenly stressed when being clamped by the substrate 21 and the clamping plate 22, six first clamping portions 212 are evenly spaced along the inner peripheral edge of the first contour hole 211. Six second clamping portions 222 are evenly spaced along the inner peripheral edge of the second contour hole 221. In other embodiments, the number of first clamping portions 212 and the number of second clamping portions 222 are not limited to being set to six, and at least one first clamping portion 212 may be set on the inner peripheral edge of the first contour hole 211, and at least one second clamping portion 222 corresponding to at least one first clamping portion 212 may be set on the inner peripheral edge of the second contour hole 221; or the number of first clamping portions 212 and second clamping portions 222 are equal and the positions correspond, and two or more first clamping portions 212 and second clamping portions 222 are both set, and there is no specific limitation.

[0023] according to Figure 4 , Figure 5 and Figure 6 As shown, in order to facilitate the rapid disassembly and assembly of the probe sheet 200, the base plate 21 and the clamping plate 22 are detachably connected through the staple assembly 50. A first mounting hole 213 is provided on the base plate 21, and a second mounting hole 223 corresponding to the first mounting hole 213 is provided on the clamping plate 22. The staple assembly 50 includes a staple member 51 inserted into the first mounting hole 213 and the second mounting hole 223, and a spring 52 sleeved on the outside of the staple member 51. The staple member 51 includes a staple head 511, a staple rod 512 connected to the staple head 511, and a pair of elastic barbs 513 connected to the staple rod 512.

[0024] During installation, the probe sheet 200 is clamped and pressed between the substrate 21 and the clamping plate 22, and the clamping piece 51 passes through the first mounting hole 213 on the substrate 21 and the corresponding second mounting hole 223 on the clamping plate 22, so that the clamping head 511 is clamped on the surface of the clamping plate 22, and the elastic barb 513 is clamped on the surface of the substrate 21. During disassembly, it is only necessary to manually squeeze a pair of elastic barbs 513, so that the pair of elastic barbs 513 are relatively retracted and withdrawn from the first mounting hole 213 on the substrate 21 and the second mounting hole 223 on the clamping plate 22 and escape from the first mounting hole 213 and the second mounting hole 223, so as to remove the clamping plate 22 from the substrate 21, so as to remove the probe sheet 200.

[0025] In order to facilitate maintaining the flatness of the surfaces of the substrate 21 and the clamping plate 22, the mounting holes are countersunk holes. When the staple assembly 50 passes through the first mounting hole 213 on the substrate 21 and the corresponding second mounting hole 223 on the clamping plate 22 to connect the substrate 21 and the clamping plate 22, the staple head 511 of the staple member 51 is hidden in the second mounting hole 223 of the clamping plate 22, and the elastic barb 513 of the staple member 51 is hidden in the first mounting hole 213 of the substrate 21; in other embodiments, the first mounting hole 213 and the second mounting hole 223 can be through holes, without specific limitation.

[0026] according to Figure 2 and Figure 3 As shown, in order to more firmly clamp the probe sheet 200 between the substrate 21 and the clamping plate 22, a first positioning hole 214 is provided on the substrate 21, a second positioning hole 224 is provided on the clamping plate 22, and a through hole 202 is provided on the probe sheet 200. After the probe sheet 200 is clamped and fixed by the substrate 21 and the clamping plate 22, the first positioning hole 214 on the substrate 21, the second positioning hole 224 on the clamping plate 22 and the through hole 202 on the probe sheet 200 can be pierced by positioning pins or positioning columns, so that the probe sheet 200 is firmly positioned between the substrate 21 and the clamping plate 22.

[0027] In this embodiment, the first positioning hole 214 is opened on the first clamping portion 212, and the second positioning hole 214 is opened on the second clamping portion 222. In other embodiments, the first positioning hole 214 can also be opened at other positions of the substrate 21, and the second positioning hole 224 can also be opened at other positions of the clamping pressure plate 22, without specific limitation.

[0028] according to Figure 2 , Figure 7 and Figure 8As shown, in order to facilitate the jig 100 to be suitable not only for wet process treatment tanks / tanks such as surface cleaning and pickling, but also for wet process treatment tanks / tanks such as electroplating, the jig 100 also includes an electrical connection structure 30. The electrical connection structure 30 includes a conductive voltage plate 31, a receiving space 32 sandwiched between the substrate 21 and the conductive voltage plate 31, and a conductive member 33 partially installed in the receiving space 32 and in conductive contact with the probe sheet 200, and another part of the conductive member 33 is constructed to be suitable for electrical connection with an electrode of a power source.

[0029] In this embodiment, the conductive voltage plate 31 is connected to the substrate 21 by screws. In other embodiments, the conductive voltage plate 31 and the substrate 21 may also be connected by other detachable connection structures, such as magnetic connection, snap connection or plug-in connection. The conductive voltage plate 31 and the substrate 21 may also be formed integrally or welded or riveted, without specific limitation.

[0030] In this embodiment, the conductive member 33 includes a conductive sheet 331 installed in the receiving space 32, and a conductive connecting portion 332 connected to the conductive sheet 331 and extending outward, and the conductive connecting portion 332 is configured to be suitable for electrically connecting to an electrode of a power source. The probe sheet 200 is pressed against the conductive sheet 331 and is in conductive contact with the conductive sheet 331. In other embodiments, at least a portion of the conductive member 33 is in conductive contact with the probe sheet 200. In addition, the conductive member 33 is not limited to the structure of the conductive sheet 331 and the conductive connecting portion 332, and may also be a conductive cable, a metal foil (such as a copper foil), a metal sheet, a metal plate, etc., without specific limitation.

[0031] according to Figure 2 and Figure 4As shown, in order to facilitate the adjustment of the immersion depth of the probe sheet 200 in the wet process treatment tank / tank, the jig 100 also includes a height adjustment mechanism 40. The height adjustment mechanism 40 is configured to adjust the height of the clamping mechanism 20 relative to the bracket 10. The clamping mechanism 20 is movably supported on the bracket 10 through the height adjustment mechanism 40. The height adjustment mechanism 40 includes a mounting groove 41 provided on the bracket 10, an adjustment frame 42 movably mounted in the mounting groove 41 along the up-down direction and connected to the clamping mechanism 20, a plurality of limit sockets 43 arranged at intervals along the up-down direction on the adjustment frame 42, and a limit plug 44 detachably plugged with the limit socket 43 and supported on the bracket 10. In this embodiment, the mounting groove 41 is provided on the support 11 and penetrates the support 11 in the up-down direction, the adjustment frame 42 is movably installed in the mounting groove 41, and the conductive connection portion 332 of the conductive member 33 extends upward and passes through the mounting groove 41 of the bracket 10, so as to be electrically connected to the electrode of the power supply. The adjustment frame 42 includes two relatively arranged adjustment rods 421, and the limit sockets 43 are provided on the two adjustment rods 421. The adjustment rods 421 are connected to the conductive voltage plate 31 by screws. In other embodiments, the adjustment frame 42 may also be an integrally formed frame structure, and the adjustment frame 42 is not limited to being connected to the conductive voltage plate 31 by screw connection. The connection relationship between the adjustment frame 42 and the conductive voltage plate 31 may also be a detachable connection structure such as snap connection, welding or plug-in, or may be integrally formed; and the adjustment frame 42 may also be detachably connected to the substrate 21, without specific limitation.

[0032] In order to facilitate better support of the limit plug-in 44 on the bracket 10 and prevent the limit plug-in 44 from accidentally falling out of the limit hole 43, limit grooves 111 for accommodating the limit plug-in 44 are opened on opposite sides of the upper surface of the support 11 of the bracket 10. When the limit plug-in 44 is inserted into different limit holes 43, the part of the limit plug-in 44 extending out of the limit hole 43 is accommodated in the limit groove 111.

[0033] During operation, the user can insert the limiting plug-in 44 into different limiting holes 43 on the adjustment frame 42, thereby adjusting the height of the clamping mechanism 20 relative to the bracket 10 to adjust the immersion depth of the probe sheet 200 in the wet process tank / pool.

[0034] In order to facilitate the user to manually lift the bracket 10 to adjust the height of the clamping mechanism 20 relative to the bracket 10, a handle 45 is connected between the two adjustment rods 421 of the bracket 10. The handle 45 is a sheet metal part with a curved protrusion in the middle. The two ends of the handle 45 are respectively connected to the two adjustment rods 421 of the adjustment frame 42 by screws. In other embodiments, the handle 45 can also be welded, glued, or snap-connected to the adjustment frame 42, which is not specifically limited.

[0035] The technical scope of the present invention is not limited to the contents in the above description. Those skilled in the art can make various deformations and modifications to the above embodiments without departing from the technical idea of ​​the present invention, and these deformations and modifications should all fall within the protection scope of the present invention.

Claims

1. A fixture for a probe sheet, suitable for clamping the probe sheet to be immersed in a wet process treatment tank for treatment, characterized in that: The fixture comprises: A support frame, configured to be supported on an upper portion of a wet process tank; A clamping mechanism, comprising a base plate movably supported on the bracket, and a clamping plate detachably connected to the base plate, wherein the base plate is provided with a first contour hole penetrating the base plate and matching the outer shape of the probe sheet, the clamping plate is provided with a second contour hole corresponding to the first contour hole and penetrating the clamping plate, the inner peripheral edge of the first contour hole is provided with at least one first clamping portion, the inner peripheral edge of the second contour hole is provided with at least one second clamping portion corresponding to the at least one first clamping portion, and the at least one first clamping portion and the at least one second clamping portion can jointly clamp the probe sheet between the base plate and the clamping plate; The electrical connection structure includes a conductive voltage plate detachably connected to the substrate, a receiving space sandwiched between the substrate and the conductive voltage plate, a conductive member partially installed in the receiving space and conductively contacting at least part of the probe sheet, and another part of the conductive member is constructed to be suitable for electrical connection with an electrode of a power source.

2. The fixture according to claim 1, characterized in that: A plurality of first clamping parts are arranged at intervals on the inner peripheral edge of the first contour hole, and a plurality of second clamping parts are arranged at intervals on the inner peripheral edge of the second contour hole.

3. The fixture according to claim 1, characterized in that: The base plate and the clamping plate are detachably connected via a staple assembly, a first mounting hole is provided on the base plate, a second mounting hole corresponding to the first mounting hole is provided on the clamping plate, the staple assembly comprises a staple piece inserted into the mounting hole, a spring sleeved on the outside of the staple piece, the staple piece comprises a staple head, a staple rod connected to the staple head, and a pair of elastic barbs connected to the staple rod.

4. The fixture according to claim 1, characterized in that: The conductive member comprises a conductive sheet installed in the receiving space, and a conductive connecting portion connected to the conductive sheet and extending outward, wherein the conductive connecting portion is constructed to be suitable for being electrically connected to an electrode of a power source.

5. The fixture according to claim 4, characterized in that: The conductive connecting portion extends upward and passes through the bracket.

6. The fixture according to claim 4, characterized in that: The conductive member is one of metal foil, metal plate, metal sheet and conductive cable.

7. The fixture according to any one of claims 1 to 6, characterized in that: It also includes a height adjustment mechanism for adjusting the height of the clamping mechanism relative to the bracket, and the height adjustment mechanism includes a mounting groove opened on the bracket, an adjustment frame movably installed in the mounting groove along the up-down direction and connected to the clamping mechanism, a plurality of limit sockets arranged on the adjustment frame at intervals along the up-down direction, and a limit plug-in that is detachably plugged into the limit socket and supported on the bracket.

8. The fixture according to claim 7, characterized in that: The regulating frame is detachably connected to the base plate or the conductive voltage plate.

9. The fixture according to claim 7, characterized in that: The adjustment frame comprises two adjustment rods arranged opposite to each other, and the limiting plug holes are arranged on the two adjustment rods.

10. The fixture according to claim 9, characterized in that: The height adjustment mechanism also includes a handle connected between the two adjustment rods.

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